Carbs are usually one of the first things to get the boot when you’re trying to shape up your diet. But cutting too many won’t help you lose weight.
The post How Many Carbs Should I Eat If I’m Trying To Lose Weight? appeared first on Women’s Health.
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Even after publishing several books and hundreds of articles that draw upon the science of ketosis and low-carb living, I keep researching, thinking, revisiting, and discussing the underpinnings of ketosis. My writing partner, Brad Kearns, and I maintain a running dialogue on all things keto. The latest conversation revolved around two very common questions or “problems” that keep coming up in the ketogenic community: why am I getting low ketone readings?
It’s a fair question. Why do some people on a keto diet register high ketones while others eating the same way register low numbers?
I won’t offer definitive answers fit to etch into stone. I will offer my exploration of the research, some educated speculation, and actionable advice you can ruminate on. And by all means get back to me with your take on the questions and my explorations, please. Dialogue is essential to understanding.
What Level of Ketones Indicates Ketosis?
The generally accepted range that indicates ketosis is 0.5-3 mmol/L. I hesitate to define a prescriptive range, though, because so many factors affect readings – what you ate for your most recent meal, how long ago you exercised, and even the instrument you used to test can affect readings.
Why do some people on ketogenic diets produce low ketone readings when they test?
There are several potential explanations for low ketone readings. Some are hypotheses, some are based on your individual biology. A few possible explanations for low ketone readings include:
- You have developed fat-burning efficiency
- Keto-adapted people may be able to burn free fatty acids
- Genetic predisposition to low ketones
- Recent exercise
- Total caloric intake
- Use of exogenous ketones
Let’s dig deeper.
You have developed fat-burning efficiency
One theory is that some keto-adapted people are so efficient at producing and burning ketones that they don’t leave any extra to spill into the urine and breath. They make only as many as they can use and their cells gobble up almost every ketone they produce. Under this argument, low ketone numbers on a ketogenic diet are a reliable sign of full ketone adaptation.
This sounds plausible, but I haven’t seen any empirical evidence that it’s the case.
Keto-adapted People May Be Able to Burn Free Fatty Acids in the Bloodstream
Another theory is that the keto-adapted have built so much fat-burning metabolic machinery in their muscles that they can burn free fatty acids directly and don’t require much additional fuel from ketones. They make enough ketones to fuel the brain, since our brain can’t run on fatty acids directly, but your muscles no longer require as many. Many people who have been in long term ketosis can get by quite nicely on 20-30 net grams of carbs a day and might only show .4 or .7 millimolar ketones on a blood test, but they have plenty of energy from burning free fatty acids and maintain muscle mass on relatively fewer calories than when they were dependent on carbs.
The evidence is inconclusive, but a few indications point to increased ability to extract energy directly from fat as a possibility.
Keto pioneers Stephen Phinney and Jeff Volek found that keto dieters blew higher readings early on in the diet when they were still burning ketones in the muscle. As they grew adapted to free fatty acids as a source of fuel and produced ketones primarily for the brain, ketone levels dropped. It was totally normal. If anything, they were more fat- and keto-adapted at lower ketone readings.
Consider the energy requirements of the brain. Whether it’s running on glucose (most of the population) or mostly on ketones, the brain is a steady state organ that never spikes energy demand. It’s a slow-burn 24/7 at nearly the same output whether you are sleeping, exercising hard, or concentrating hard. While the brain has a substantial caloric requirement (at roughly 2% of our body weight, it uses 20% of our resting metabolic rate), you don’t need a ton of glucose or ketones at any one time to power your brain gracefully all day long. That’s why people can “get away” with lower ketone production and still reap the benefits we expect from eating this way.
Genetic Predisposition to Low Ketones
There’s almost certainly a genetic component to ketone production, too. Take the Inuit, who were rarely in ketosis despite traditionally eating a very low-carb diet.1 It takes several days of deep fasting for them to produce measurable ketones. Yet, they are adept at burning free fatty acids, almost as if they “skip” keto-adaptation and proceed directly to burning fat. Other variants that affect ketone production have yet to be discovered, but they’re out there.
Recent Exercise or Otherwise Increased Energy Demand
If you test your ketones before and after you exercise, you may be surprised to find that your numbers are quite different after you’ve worked out. Remember, ketones are an energy source, not a stamp of accomplishment. Ketones are consumed when there is an energy demand in your body. It doesn’t mean you messed up your diet. Quite the opposite – it simply means your body used the energy source available at the time. Once ketone bodies are in low supply, your body will burn fat to make more, and that’s a win.
Why do Some People on Long-term Keto Diets Still Get High Ketone Readings?
A few of the previous theories assume that you develop an increased ability to burn fat after you have been in ketosis for a while. But there are people who, after being in ketosis for a long period of time, still get high ketone readings when they test. What gives?
Total caloric intake is a factor in ketone levels
A major factor not often mentioned in whether someone on a keto diet registers high or low ketones is overall calorie intake. How much food are you eating?
Ketones are generated when the amount of dietary fat available to be burned exceeds the supply of oxaloacetate (provided by protein or carbohydrates). It’s not that the body thinks, “This woman needs some ketones, stat.” It’s more like, “I’ve got too much acetyl-COA from all this fat, and I can’t find any oxaloacetate. Time to ask for ketones!” If you’re the type to use keto to justify chugging olive oil, you’ll generate lots of ketones simply because your fat intake is outpacing the supply of oxaloacetate. Keto athletes eating tons of calories will probably produce more ketones simply because they’re eating so much fat.
If you’ve attained “caloric efficiency” and are eating fewer calories overall, you’ll generate fewer ketones but still experience all of the benefits of being in ketosis.
Use of exogenous ketones result in high ketone readings
Another factor is the use of exogenous ketones. Realistically, you could take your ketone readings, then take keto salts or keto esters, then take your readings again and see a bump. That is what they’re for.
Don’t Get Caught Up in the Numbers
Above all else, focus on how you feel.
- Can you go without a meal and maintain steady, even energy and concentration?
- Are you losing body fat, or are you happy with your body composition?
- Are you thinking more clearly?
- Has the keto flu come and gone?
- Are aerobic activities easier than ever?
If you’re experiencing the benefits of ketosis, there’s no need to fret over some numbers on a device. The numbers can’t negate your real world experience.
The post Why Am I Getting Low Ketone Readings on a Ketogenic Diet? appeared first on Mark’s Daily Apple.
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A little planning and motivation will help you start a low-carb, keto, or Primal lifestyle, and under normal circumstances, keeping your carbs on the low side is easy. But let’s not create the illusion that it is easy all the time. From time to time, you may get stressed and eat mindlessly. Or, your aunt drops off her blue-ribbon cake that you’ve loved since you were in preschool, and you give in, just this once. Or, you had a jam-packed day and all you can muster to make for dinner is that package of gluten-free noodles in the back of your pantry. The next thing you know, you’ve eaten enough carbs for a week, and you wonder how you’ll get back into ketosis after a carb binge.
The short answer is, yes you will recover from a carb binge. Yes, you will get back into ketosis. As far as how long it will take to get back into ketosis – that depends on numerous factors, that we’ll dive into here. The important thing to remember is, you did not obliterate your goals with one misstep. Especially after you’ve spent some amount of time in ketosis, your body will allow for fluctuations in carb consumption here and there. That’s called metabolic flexibility, which we’ll go into shortly.
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Can You Have a Cheat Day on Keto or a Primal Diet?
Admittedly, I’m not a fan of calling them “cheat days,” for a few reasons:
- “Cheating” implies that you did something wrong and should feel guilty about it.
- Earmarking “cheat days” sends the message that you can eat whatever you want that day with abandon. You’d be surprised how much you can backpedal on your goals in a 24-hour period.
I prefer to frame higher carb meals or snacks as carb cycling or carb refeeding, which is an intentional higher carb meal to enhance your results; or, frame them as treats, which are planned. That way, the extra carbs are enjoyable, planned in advance, and come with limitations so you don’t go overboard. And, there’s no guilt involved.
So, can you have high-carb days on keto? If you are in ketosis and have a sudden surge in sugar or carbs, your body will burn glucose instead of producing ketones. In order to get back into ketosis, you have to use up the glucose you just consumed, and the glycogen your body just stored.
The concern is whether the transition back into ketosis will be as difficult as you remember from those first days cutting carbs. If you have been in and out of ketosis for a while, you may slip back into ketosis fairly easily because you’ve developed metabolic flexibility. If you’re just starting, you may go through some of the discomfort of transitioning between fueling with sugar vs. fueling with ketones. Your body “remembers” though, and most likely, it will not last as long or be as severe. This article contains some things you can do if you experience “low-carb flu.”
What Happens to Your Body After a Carb Binge?
So, you decided to give in. First, don’t beat yourself up. It happens. What does your metabolism do with the surge of insulin and carbs? Even a few quick forkfuls can shift you from small doses of quality carbs wisely spread throughout the day to possibly 100 or more grams of pure sugar in one sitting. It’s likely you’ll experience some effects, but you can get past it.
First off, the good news. There’s no carb police coming to take away your keto card. Nor is there any other permanent fate awaiting you. You’ll go about your day a live, generally functional human being. There is no truly long-term risk elevation for that matter. Nonetheless, you’ll likely experience a fair amount of regret for cheating on keto.
- Your Pancreas Kicks Into Overdrive. Within a few minutes, your pancreas starts pumping out a flood of insulin to try to sop up all the excess glucose that’s suddenly rushing through your bloodstream. Remember, while glucose is muscle fuel when it’s in the muscles, it’s toxic sludge when it stays in your bloodstream. Your body knows that and does everything it can to get it out of there. Perhaps you’re feeling flushed, a little high, spastic, anxious, or nauseous depending on how much you ate, how big you are, what your normal carb load is, and how acutely you tend to “feel” the effects of sugar and other substances. Ironically, if you were insulin resistant, you might not even notice these sensations.
- Excess glucose converts into body fat. The gush of insulin now creates a see-saw effect. If your glycogen stores have room, some of the sugar goes into muscles. If there’s no more room, the excess goes into fat cells, where it is stored as fat. In reaction to this quasi-emergency that your brain perceives as a life-threatening stress, the body steps up its efforts to achieve homeostasis by releasing both epinephrine (adrenaline) and cortisol from your adrenals. Your heart starts racing, and you’re starting to feel uncomfortable, maybe even sweating. And we’re still likely within the first hour after you finished off that cake!
- Sugar crash. After a bit more time passes, burnout settles in? That’s called a sugar crash – when all the glucose is gone from the bloodstream and you start to feel sluggish, off-kilter, like the internal circuits are all fried after sparking in a heap of now smoldering wires.
- Your immune system slows down. The havoc that sugar rush set off – the swing of glucose and insulin, the cortisol and adrenaline – they’ve sent your immune system into a tailspin. Researchhttp://jcem.endojournals.org/cgi/content/abstract/85/8/2970?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=1&andorexacttitle=and&andorexacttitleabs=and&andorexactfulltext=and&searchid=1&FIRSTINDEX=0&sortspec=relevance&volume=85&firstpage=2970&resourcetype=HWCIT‘>2 on the body. Your blood even thickens as a response to the stressors. A hefty dose of sugar can compromise the immune system
One of the more common questions we get in the Keto Reset Facebook community is, “How do I break through a weight-loss plateau?”
Stalls are frustrating. You’re cruising along on your Primal or Primal + keto diet, and then wham—you hit a wall. It’s all a totally normal and expected part of the weight loss process. Weight loss is never linear. There are always downs, ups, and flat spots.
In fact, if you’ve been losing weight for a while, and then you stall out for a week or two, I wouldn’t even consider that a plateau necessarily. Your body might keep losing weight on its own if you give it time and don’t stress about it. Still, I get it, you’re eager to kick-start the weight loss again.
One strategy that gets tossed around is trying a carb refeed or “carb up.” Carb refeeds are touted as plateau busters and also, more generally, as a strategy to support weight loss. In today’s post, I’ll explain the logic behind this idea and explain why it might be effective, especially for women following a generally low-carb approach.
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What Is a Carb Refeed?
Let’s get some terminology out of the way. Strategically adding carbs to a low-carb diet is variously called a “carb refeed,” “carb up,” or “carb cycle.” These terms don’t have standardized definitions. In general, carb cycling usually refers to eating low carb for a certain number of days, then higher carb for a certain number of days, and repeating.
“Carb refeed” and “carb up” can mean the same thing, or they can mean adding carbs more intuitively when you feel like you need them.
Carb cycling strategies have long been used to promote leanness, especially by physique and other athletes trying to achieve low body fat percentages. In this context, carb cycling involves specific protocols, usually 5-6 days of very low carb eating combined with 1-2 days of higher carb eating. They may include exercise and fasting regimens, too.
The carb cycling protocols used for getting super lean aren’t the same as what we’ll be talking about for general weight loss and breaking out of a stall. For one thing, they usually involve more carbs than you probably need. We’ll get to that later. Also, although some of the mechanisms are probably the same, they focus specifically on depleting and refilling glycogen stores. For our purposes, that’s not so important.
How Do Carb Refeeds Work?
First let me say that the evidence for carb cycling strategies, especially with regard to weight loss and plateaus, is mostly anecdotal. There is pretty good data to support the pieces, but the whole picture has not been rigorously tested.
So what do we think is happening? There are a few (not mutually exclusive) hypotheses here:
- Carb refeeds work by boosting leptin
- Carb refeeds work by relieving the stress of dieting
- Dieting is hard, and carb refeeds help us stick to them
Carb Refeeds Work by Boosting Leptin
Leptin is sometimes called the “satiation hormone,” but it’s probably more accurate to think of it as a starvation sensor.1 Its main role is to tell the brain whether we have sufficient energy on board, either in fat cells, which secrete leptin, or because we have recently eaten (especially carbs).
It’s well established that leptin levels drop both when we lose body fat and when we eat in a caloric deficit2 for even a short period. Remember, from an evolutionary perspective, weight loss signals that we are in a time of food insecurity and stress. Low leptin signals to the hypothalamus that we might be facing an energy shortage. In turn, the hypothalamus kicks on the processes collectively known as adaptive thermogenesis,3 or energy conservation. These include down-regulating thyroid activity and slowing metabolic rate, decreasing energy expenditure, and increasing hunger and appetite.
Premenopausal women’s bodies are especially sensitive to anything that sets off the “Danger! Starvation possible!” alarms. (Postmenopausal women are generally more resilient.) Leptin is a key player in that system. It is also involved in the regulation of insulin sensitivity and glucose metabolism, the female reproductive and immune systems, and skeletal and cardiovascular health. Basically, leptin is really important if we want to feel good and achieve optimal hormonal balance.
Leptin levels rise in response to eating carbohydrates specifically.4 Thus, one rationale behind carb refeeds is that by boosting leptin, we can reset the system. Basically, it tells the brain, “Hey, it’s cool, we have food around. It’s safe to let go of some of this body fat.”
Carb Refeeds Work by Relieving the Stress of Dieting
A related hypothesis is that dieting is physiologically stressful on the body. After periods of energy restriction, we see a decrease in thyroid hormones and an increase in cortisol (which may be related to falling leptin). These are part of the adaptive response that aims to restore energy balance. Carb refeeds alleviate the stress of being in a constant state of energy restriction.
Dieting Is Hard, and Carb Refeeds Help Us Stick to Them
One of the main reasons dieting hard is because of hormonal changes (ahem, leptin5) that increase hunger and appetite. Besides feeling unpleasant, this leads many dieters to eat more than they realize, undermining fat loss. Multiple studies also suggest that low leptin levels increase reward-seeking behavior. Basically, food becomes more appealing and harder to resist.
Low leptin is also related to depression6, anxiety, and perceived stress, all of which can make it harder to stick to your diet goals.
For all these reasons, periodically boosting your leptin via carb refeeds should make dieting feel less challenging. Beyond that, there’s also the psychological factor of knowing that you don’t have to strictly adhere to a diet indefinitely. Although it might seem counterintuitive, research confirms 78that giving yourself planned breaks can help relive the doldrums of dieting and actually increase your adherence in the long term.
Who Should and Should Not Consider Incorporating Carb Refeeds
There’s no evidence that carb refeeds are necessary or optimal if weight loss is your goal. Like so many things, this is going to be an n=1 situation. They might help, hurt, or be neutral depending on the individual.
First and foremost, if it ain’t broke, don’t fix it. If your current diet is working just fine, you feel great, and you’re losing weight, you don’t need carb refeeds. (By the way, if you’re impatient because you’re losing slowly, I haven’t seen any evidence that they will speed up weight loss.)
Likewise, they generally aren’t recommended for people who still carry a significant amount of body fat. There’s no real guidance as to what constitutes “significant amount,” unfortunately. As a rule, though, leaner individuals are more likely to benefit from the hit of leptin because they have less adipose tissue to produce it on a day-to-day basis.
DO: Reasons to experiment with carb refeeds include:
- You’re experiencing a weight loss plateau. This means several weeks of no change in weight or body measurements despite nothing else changing. This isn’t a guaranteed strategy, of course. There are lots of reasons weight loss can stall, not all of them related to leptin or diet adherence. It’s certainly worth a try, though.
- You’ve been low-carb and/or calorie restricted for a while, and you’re experiencing other signs of hormone dysregulation. These include menstrual irregularity and sleep9 disruptions, among others. Depending on how severe your symptoms, you might need more than the occasional carb refeed. For mild symptoms, an occasional refeed might help.
- You’re sick of dieting. Mixing it up with carb refeeds (which are not the same as “cheat days”) can relieve the dieting fatigue.
DON’T: Other instances when carb refeeds are not advised are:
- For people who are using low-carb or keto therapeutically, such as for epilepsy or Parkinson’s, unless advised by their health care practitioners.
- For people who are extremely insulin resistant.
How to Implement Carb Refeeds
No matter what strategy you use, you want to refeed with nutrient-dense, Primal-aligned foods. We’re talking sweet potatoes, potatoes, beets, baked goods made with almond or coconut flour if you want, in-season fruit, quinoa, maybe legumes if they work for you. If you want to eat some rice (sushi!), no judgement here.
Primal carb refeeds aren’t just an excuse to “cheat” (a term that I hate). You’ll see carb cycling protocols that allow, even advocate, eating copious amounts of junk food (another term I don’t love) on refeed days. Since our goal here is metabolic health and hormone balance, stick to the same Primal foods that support those goals, just with more carbs.
How Many Carbs Should I Add?
If you look at the literature on carb cycling, you’ll find various opinions. Depending on who you ask, it can be upwards of 300+ grams per day. Again, though, these come mostly from protocols aimed at physique and other athletes, and these high carb recommendations are for men who are already quite lean. It’s not clear how they apply to the average woman looking to kickstart their weight loss.
As usual, it’s also hard to find research on people who follow a low-carb Primal or paleo approach. In this oft-cited study,10 for example, the control diet was a mainly liquid diet supplemented with orange juice, yogurt, and cream that came in at an average of 224 grams of carbs per day. In the carb overfeeding condition, which was shown to boost leptin, the average daily carb intake was 394 grams—way more than the average Primal eater probably consumes.
In the absence of solid research-based recommendations, you’ll have to experiment. A good place to start is bumping up to twice your normal daily intake by adding nutrient-dense carbs to one or two of your meals, and increasing as necessary. If you want to be scientific about it, log your food and also keep track of metrics like weight, sleep, and energy. Play around with the frequency of carb-ups, as well as the amount of carb you add, and see what works best.
Should You Increase Carbs, Calories, or Both?
Technically, carb refeeds don’t have to involve more calories. Some protocols state that you should reduce fat on carb-up days so that your total caloric intake stays the same. Others specifically recommend adding carbs and increasing calories by a fixed amount.
Unfortunately, we don’t have enough studies to break down the separate effects of carbs and calories here. In theory, both should signal to the body that energy is available, but carb intake uniquely boosts leptin. Once again, experiment to see what works for you. To start, I’d recommend allowing your calories to increase on refeed days. You might dial back your fat a little, but I wouldn’t overthink it, especially if you’re already low-carb or keto. Adding 50 or 75 grams of carbs is 200 to 300 calories. That might be less than your typical caloric deficit. Even if you add more, it’s unlikely to negatively effect weight loss if we’re talking occasional refeeds.
I know that many dieters are afraid to increase their calories for fear of “undoing” their progress. That fear seems to be unfounded. Multiple studies confirm that intermittent dieting—mixing periods of caloric restriction with eating around your maintenance calories—is no worse11 for losing weight than continuous calorie restriction. It may even be advantageous12 for weight loss, and fat loss specifically.
How Often Should I Refeed?
In terms of how often to refeed, you have some options:
- Add in carbs whenever you plateau
- Carb cycling on a schedule
- Carb cycling around your menstrual cycle
- Eating carbs intuitively
Add in Carbs Whenever You Plateau
If you’re actively trying to lose weight, one option is to wait until you hit a plateau—at least a couple weeks when the scale stops moving—then add a day or two of higher-carb Primal meals to see if that moves the needle.
Carb Cycling on a Schedule
As I said up top, some carb cycling strategies involve fixed periods of lower- and higher-carb eating. Often this looks like eating low-carb during the week and then doing one or two higher-carb days on the weekend. This is more convenience than science though. There’s no reason you can’t do 9/1 or 12/2 or any other pattern that works for you. You don’t even need to take a whole day. Some people just do one high-carb meal per week and feel great.
Obviously this strategy is more of a lifestyle than an acute tool for breaking through a weight-loss plateau. This is for people who don’t do well with continuous dieting or who find it easier to stick to their goals when they have planned deviations. It is akin to the idea of a cyclical ketogenic diet, although you don’t have to be keto to use carb cycling.
Carb Cycling Around Your Menstrual Cycle
Another carb cycling strategy is timing carbs strategically around your menstrual cycle.
This strategy isn’t specifically geared at weight loss but rather supporting the whole hormonal system, but it potentially allows you to kill two birds with one stone. There are different approaches here, but a common one is increasing carbs 4 to 5 days post-ovulation (around days 19 and 20 of your cycle) and on the first couple days of your period. These are times when your leptin levels naturally dip, so you could possibly benefit from the boost. Some women prefer instead to add carbs around ovulation, days 13 to 15. Again, see what works be for you.
Eating Carbs Intuitively
Finally, you can wait until your body starts calling out for carbs and respond appropriately. In my opinion, intuitive eating is one of the goals of a Primal diet and lifestyle. When we improve hormone balance and tap into how good it feels to nourish ourselves with nutrient-dense foods, we should be able to trust when our inner voice says, “Hey, I could use some starchy vegetables here!”
Eating carbs intuitively isn’t the same responding to sugar cravings or eating something off plan just because it “sounds good.” I think we can all recognize the difference between listening to our bodies and eating purely for pleasure. (You’re more than welcome to do that too, but it’s not what we’re talking about here.)
Intuitive carb refeeds are probably going to work best for people who have been on the Primal train for a while and who generally feel pretty in tune with their bodies. Women who are dealing with chronic health issues or hormone imbalances might need something more structured.
Note that this is a different question than carb timing, which Mark covered recently. Carb timing is about when to eat your carbs during the day.
Don’t Be Afraid to Experiment
I’m a big fan of experimenting with your diet. There is so much bioindividuality, it’s impossible to find a one-size-fits-all approach. The best strategy for you is the one that hits that sweet spot where you to feel your best and also enjoy how you eat.
Moreover, I’m going to go out on a limb and say if you’ve been low-carb for so long that you’re afraid to consider eating even nutrient-dense, Primal-aligned carb-y foods like sweet potatoes, you should challenge yourself to try a carb refeed and see what happens. I’m not talking about people who know they feel better eating very-low-carb and simply don’t have the desire to switch it up. I’m talking about people who have a mental block around the very idea of carbs. We don’t want people to get “stuck” in a low-carb paradigm to the point where they feel unable to enjoy otherwise nutritious foods just because they have more carbs than, say, broccoli.
Finally, although their are good reasons to try carb refeeds if your current low-carb diet isn’t working the way you want, it’s only one of many things you might try. In particular, if you haven’t also gotten your sleep and stress in order, make those priorities as well. Carb refeeds can only do so much if you don’t have a solid foundation of healthy habits in place.
Tell us: Have you had success implementing a carb cycling approach? What works for you? What are your favorite foods to use to increase carb intake?
Related posts from Mark’s Daily Apple
The post Carb Refeeds for Women: Do They Help With Fat Loss? appeared first on Mark’s Daily Apple.
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Are carbs really the waist-expanding enemy we’ve been led to believe they are? A dietician weighs in on this touchy topic…
The post Do You Really Need To Give Up Carbs To Lose Weight? appeared first on Women’s Health.
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It seems every “keto for women” forum abounds with stories about menstrual cycles gone wild in the first few months of keto. Irregular cycles, breakthrough bleeding, and periods lasting much longer than normal are common complaints. Sometimes these stories are cited as evidence that keto isn’t good for women, at least not premenopausal women, and that we need carbs for healthy hormones. Yet, many women don’t notice any changes in their menstrual cycles at all, while others report improvement in PMS symptoms and cycle regularity from the get-go.
What gives? Why do some women’s cycles apparently become wacky when they start keto, while others feel like keto is the key to period bliss? Can keto “mess up” the menstrual cycle?
We know that diet—what and how much we eat—can profoundly affect our hormones. This is true for both women and men. One of the reasons people are so excited about ketogenic diets is specifically because keto shows promise for helping to regulate hormones and improve cellular sensitivity to hormones such as insulin and leptin.
At the same time, women’s hormones are especially sensitive not only to dietary changes but also to downstream effects such as body fat loss. Furthermore, one of the ways women’s bodies respond to stressors is by turning down the dial on our reproductive systems. It’s reasonable to hypothesize, then, that women might have a tougher time adapting to or sustaining a ketogenic diet. Keto can be stressful depending on one’s approach, and that might negatively impact women’s reproductive health. But do the data actually bear that out, or is so-called “keto period” more misplaced hype than genuine fact?
Note that throughout this post, I’m going to use the term “reproductive health” to refer to all aspects of women’s menstrual cycle, reproductive hormones, and fertility. Even if you aren’t interested in reproducing right now, your body’s willingness to reproduce is an important indicator of overall health. When your reproductive health goes awry—irregular or absent periods (amenorrhea) or hormone imbalances—that’s a big red flag. Of course, post-menopausal women can also experience hormone imbalances that affect their health and quality of life (and low-carb and keto diets can be a great option for them).
Menstrual Cycle 101
Let’s briefly review what constitutes a normal, healthy menstrual cycle, understanding that everybody’s “normal” will be a little different. A typical cycle lasts from 21 to 24 days on the short end to 31 to 35 days on the long end, with 28 days being the median. Day 1 is the first day of your period and begins the follicular phase, which lasts until ovulation. Just before ovulation, levels of luteinizing hormone (LH), follicle stimulating hormone (FSH), and estradiol (a form of estrogen) spike. Next comes the luteal phase covering the approximately 14 days from ovulation to menses. LH, FSH, and estradiol drop, while progesterone rises. Estradiol bumps up again in the middle of the luteal phase. If a fertilized egg is not implanted, menstruation commences, and the whole cycles starts over again. All this is regulated by a complex communication network under the hypothalamic–pituitary–gonadal (HPG) axis, which is closely tied to the actions of the adrenal (the A in HPA axis) and thyroid glands.
Across the cycle, fluctuations in body weight are common as fluid is retained and then released along with shifts in estrogen and progesterone. Changes in blood glucose are also normal, and insulin-dependent diabetics often find that they need to adjust their dose at different times of their cycles to keep their blood sugar in check. The most common pattern is higher blood glucose readings in the pre-menstrual period (the second half of the luteal phase), and lower readings after starting your period and before ovulation. This is generally attributed to the fact that progesterone, which is highest during the luteal phase, is known to reduce insulin sensitivity. However, different women experience different patterns, which can also be affected by other factors such as oral contraceptive use.
Normal fluctuations in insulin resistance and blood glucose can mean that women get lower ketone readings at certain times of the month than others. When these occur premenstrually—and so they tend to coincide with a period of (transient) weight gain and food/carbohydrate cravings—women often feel as though they are doing something wrong. Rest assured that these variations reflect normal physiology.
The many factors that affect your cycle and the levels of your sex hormones include: other hormones, gut health and microbiome, metabolic health (e.g., insulin sensitivity), environmental toxins, stress, sleep, immune health, nutrient deficiencies, activity level and energy expenditure, and age. Each affects the others, and all (except age of course) can be affected by diet. It’s no surprise, then, that it can be extremely difficult to pin down a root cause of menstrual changes or reproductive issues.
What the Research Tells Us About Keto and Menstruation
As I said at the outset, there are lots of anecdotes, both positive and negative. In my experience, most women whose cycles seem to go crazy when they start keto find that things get back to normal—and often a better version of normal—after a few months.
First, it’s tricky to determine the effects of keto per se, since many people combine a ketogenic diet with calorie restriction (intentionally to lose weight or unintentionally due to the appetite suppressing effects of keto) and with fasting (intermittent and/or extended). Each of these can independently impact the factors listed above, lead to weight loss, and affect the menstrual cycle and reproductive health.
So, is there any evidence that keto itself causes changes to menstruation?
The scientific evidence is scant….
The one statistic you’ll see floating around the interwebs is “45% of (adolescent) females experience irregular menstrual cycles on keto.” This statistic comes from one small study of adolescent girls using a therapeutic ketogenic diet to treat epilepsy. Six of the twenty girls reported amenorrhea (loss of period) and three were diagnosed with delayed puberty. However, the ketogenic diet used for epilepsy is different and usually much stricter than an “everyday” keto diet needs to be, and epilepsy is frequently associated with menstrual dysfunction regardless of diet.
To extrapolate the findings of this study and argue that nearly half of teenage girls (or women generally) are likely to experience menstrual problems from going keto is a huge leap.
The fact is, I’m unable to find any studies done in healthy human females (or mice for that matter) demonstrating that otherwise normal menstrual cycles are disturbed by going keto.
5 Ways Keto-Related Factors *Might* Affect Your Menstrual Cycle
With the limited amount of research looking directly at keto and menstruation, let’s look first at whether there are direct effects of carbohydrate restriction or elevated ketone production on the menstrual cycle. Those are the defining characteristics of keto and what differentiates keto from other ways of eating. Then we can examine indirect effects that occur due to factors such as weight loss. These are not unique to keto, though they might be more likely on a ketogenic diet compared to other ways of eating.
There is no real body of evidence that looks at ketogenic levels of carb restriction and menstruation, but there are some clues. In this small study, functional hypothalamic amenorrhea (FHA) was associated with dietary fat restriction; women with FHA actually ate non-significantly more carbs than matched controls and nearly identical total calories. Likewise, in this small study, FHA was associated with lower fat intake but no significant difference in carb intake.
This meta-analysis looked at the effect of low-carb (not keto) diets on markers of reproductive health among overweight women. The researchers found four studies that examined effects on menstruation; all showed improved menstrual regularity and/or ovulation rates. Of six studies that looked at levels of reproductive hormones, five reported significant improvements.
Carb restriction also results in decreased insulin production. Hyperinsulinemia and insulin resistance are frequently associated with polycystic ovarian syndrome (PCOS), one of the leading causes of female infertility and a frequent cause of menstrual irregularity. There is currently a lot of interest in using keto to treat PCOS, but only one small study has so far directly tested the effectiveness of a ketogenic diet to treat PCOS, with positive results.
No studies have looked at the direct effects of ketones on menstruation.
Of course weight loss is not unique to keto, but keto can be very effective for weight loss. Some women experience rapid weight loss when first starting a keto diet. Weight loss in and of itself can impact menstruation through a variety of pathways. A key way is by reducing the hormone leptin. Leptin’s main job is to communicate energy availability to the hypothalamus—high levels of leptin tell the hypothalamus that we have enough energy on board, which also means we can reproduce. Low leptin can disrupt the menstrual cycle and is linked to hypothalamic amenorrhea.
Body fat loss can also affect estrogen levels since estrogen is both stored and produced in adipocytes (fat cells). While fat loss in the long term will decrease estrogen production, it is possible that rapid fat loss might temporarily raise estrogen levels and can also affect estrogen-progesterone balance. These transient changes in estrogen levels might underlie some of the menstrual irregularities women report.
Stress can impact the menstrual cycle in myriad ways. Cortisol acts on the hypothalamus and pituitary glands, affecting hormone levels, sleep, immune function, and gut health, to name a few. Diets can be a source of stress, both at the physiological and psychological levels. Keto has a reputation for being especially stressful because it is more restrictive than other low-carb diets, but this can be mitigated by following the Keto Reset tips for women.
Thyroid dysregulation is another common cause of menstrual irregularities, and there remains a pervasive belief that keto is bad for thyroid health. Indeed, the thyroid is sensitive to nutrient deficiencies and caloric restriction, and thyroid hormones, especially T3, do frequently decline on keto. However, as Mark has discussed in a previous post, changes in T3 levels might not be a problem, especially in the absence of other problematic symptoms. Moreover, many practitioners now use keto as a cornerstone in their treatment of thyroid disorders.
What Should I Take From These Findings?
The first takeaway: there just isn’t much direct evidence about how keto might affect your menstrual cycle, positively or negatively. We have some studies suggesting that low-carb diets improve some aspects of menstruation and reproductive health, but keto is more than just another low-carb diet. Ketones themselves have important physiological properties, such as being directly anti-inflammatory, which might positively impact women’s reproductive health.
Second, the ways that keto is likely to (negatively) affect menstruation aren’t unique to keto, they’re common to any diet: hormone shifts mediated by energy balance, stress, and weight loss.
Furthermore, since keto is so often combined with caloric restriction, time-restricted eating, and fasting, even the anecdotal evidence might not be able to tell us all that much. If a woman is eating ketogenically, in a big caloric deficit, and doing OMAD (one meal a day), and her leptin plummets, how are we to know what really caused it? We don’t have good evidence that otherwise healthy women start a well-executed ketogenic diet and end up messing up their menstrual cycles.
That said, women do need to be cognizant of the sum total of the signals they are sending their bodies when it comes to energy availability and stress. A lot of women come to the keto diet with a history of adrenal, thyroid, metabolic, and reproductive issues. It’s important that they’re extra careful about how they approach keto. Done correctly, it might be just what the doctor ordered. I encourage any woman who’s dealing with other hormonal issues to work with a medical practitioner to tailor a keto diet to her unique needs.
But I’m Telling You, Keto Made My Period Go Haywire!
Ok, I believe you, really! But changes do not necessarily equal dysfunction. It is normal to experience hormone fluctuations when you make a massive—or even a relatively small but important—shift in your nutrition. Sometimes those fluctuations are unpleasant or unwanted, such as a period that lasts 14 days or one that arrives a week before you planned while you’re on vacation. However, that doesn’t make them bad from a health perspective. We need to respect that our bodies are dynamic systems. Changing the input will invariably change the output, and the system might need a few months to adapt to a new normal.
If your cycle goes wonky but you’re otherwise feeling good, give it a few months to sort itself out. If after a few months it’s still all over the place (or definitely if you’re having other disruptive symptoms), enlist help. In the meantime, check to make sure you’re not short-changing yourself nutritionally or calorically. Scale back on fasting efforts, and consider shifting more toward a traditional Primal way of eating.
At the end of the day, if you go keto and experience negative effects, stop. Keto is super hyped right now, but if your body is sending you clear signals that keto is not a good approach for you at this time, don’t do it. You can always try again later. It might be that your first attempt at keto didn’t work, but with a few adjustments and some experimentation over time you can find a version of keto that works for you.
Thanks for reading, everyone. Do you have comments, questions, or feedback? Let me know below.
Comninos AN, Jayasena CN, Dhillo WS. The relationship between gut and adipose hormones, and reproduction. Human Reproduction Update 2014; 20(2): 153–174.
Fontana R, Della Torre S. The Deep Correlation between Energy Metabolism and Reproduction: A View on the Effects of Nutrition for Women Fertility. Nutrients. 2016;8(2):87.
Klok MD, Jakobsdottir S, Drent ML. The role of leptin and ghrelin in the regulation of food intake and body weight in humans: a review. Obesity Reviews 2007;8(1):21-34.
Meczekalski B, Katulski K, Czyzyk A, Podfigurna-Stopa A, Maciejewska-Jeske M. Functional hypothalamic amenorrhea and its influence on women’s health. J Endocrinol Invest. 2014;37(11):1049–1056.
Tena-Sempere M. Roles of Ghrelin and Leptin in the Control of Reproductive Function. Neuroendocrinology 2007;86:229-241.
The post Keto and the Menstrual Cycle: Is There Reason To Worry? appeared first on Mark’s Daily Apple.
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While some keto or low-carb proponents claim fiber is useless at best and actively harmful at worst, I come down on the side that says fiber is probably helpful for most people. Some folks have persistently better responses to low- or no-fiber keto diets, and I won’t argue with that—I’ve seen it happen and I’ve read the studies where de-emphasizing fiber can actually improve constipation, for example.
I’ll just say that I have an opposite reaction, and, most importantly, I love eating a variety of plant foods that also happen to contain a ton of great nutrients in addition to fiber.
Do I buy into the idea that fiber is important because it is every human being’s responsibility to produce as much colonic bulk as humanly possible? No.
Do I think we should be consistently pushing the limits of our digestive tracts, performing feats of bathroom heroism so momentous they border on Herculean, and making sure the toilet bowl buckles beneath us? No.
The real value of fiber lies not in its coarseness, its tendency to form colonic bulk, to keep us topped off. The true value lies in its fermentability. A fermentable fiber is a prebiotic fiber—fiber that feeds our gut bacteria.
I will, however, explain why we need to be feeding our gut bacteria. Our gut bacteria form a physical barrier against incursions and colonization by pathogenic bacteria; they take up room along the gut lining so pathogens can’t. If we don’t feed our gut bacteria with prebiotics, it won’t be around to protect us. After antibiotic treatment where both good and bad gut flora are indiscriminately targeted and wiped out, pathogenic obesity-promoting bacteria take advantage of the open space. That’s a worst-case scenario, but it shows what can happen when the harmony of the gut is disturbed by antibiotics or, to a less extent, a lack of fermentable prebiotic fibers.
Gut bacteria also convert antinutrients like phytic acid into nutrients like inositol. The almond meal-obsessed keto eater would do well to have a powerful gut biome set up to convert all that phytic acid to inositol.
Now, some writers will come up with specific blends of fibers, powders and gums to create the “optimal” prebiotic diet for your gut bacteria, but that’s pretty silly. The gut is a complicated place. We’ve barely begun to even identify all its inhabitants. To think we know the precise blend of isolated fiber that will make them flourish, and then act on that, is a mistake.
1) Almonds and Pistachios
Nuts are usually favored in health-conscious circles for a few reasons. They like the monounsaturated fat. They like the mineral profile, or the complete protein, or their ability to dissemble into nut meals and form baked goods. But what gets short shrift is the fiber content. Now, I can’t speak for other nuts, but almonds and pistachios in particular contain fiber with potent prebiotic effects. People who eat almonds and to an even greater extent pistachios end up with improved gut bacteria profiles.
2) Green Bananas
Ripe bananas are difficult to squeeze into a ketogenic diet. The green banana—an unripe one—is mostly resistant starch, a type of starch that cannot be digested and travels untouched until colonic bacteria metabolize it. It’s one of the best stimulators we know of butyric acid production. And sure, you could do a spoonful of raw potato starch to get your resistant starch, but the beauty of the green banana is that it also provides potassium, another nutrient that some find difficult to obtain and stay keto.
3) Wild Blueberries
Blackberries, boysenberries, raspberries, and strawberries are all loaded with fiber, and you should eat them. They’re lower carb than you think, they’re loaded with polyphenols, and topped with some real whipped cream they make a fantastic dessert. But wild blueberries are special. They’re smaller than other berries, which increases the amount of skin per ounce you get, and skin is where all the polyphenols and fiber lie. Heck, even the blueberry’s polyphenols have prebiotic effects on the gut biome.
A few years ago, I wrote a whole post on mushrooms. Suffice it to say, they’re quite wonderful, bordering on magical. I did not discuss the fiber they contain. It turns out that all the various mushroom polysaccharides/fibers, including beta-glucans, mannans, chitin, xylans, and galactans also act as potent prebiotics that improve the health of the host.
Your standard avocado has about 12-15 grams of fiber, if you eat the whole thing. I
Great with chili powder, salt, and lime juice, jicama is about 11 grams of carbs per cup, but half of those are inulin, a potent prebiotic fiber with a tendency to really ramp up butyrate production.
Onions are another fantastic source of inulin. They go into almost every dish of every cuisine, so there’s no excuse not to be eating onions.
I’ve been known to treat garlic like a vegetable, roasting an entire cast iron pan full until brown and sweet and chewy. They’re another great source of prebiotic fiber.
Broccolini is a major part of my favorite meal of the day—my Big-Ass Keto Salad. Broccoli (and cruciferous vegetables in general) has been shown to have modulatory effects on the gut biome.
12) Dark Chocolate
13) Animal Fiber
Obligate carnivores like cheetahs who don’t eat any plants (willingly) still have gut bacteria. These gut bacteria thrive on “animal fiber,” the gristle and cartilage and other bits of connective tissue that comprise a good 20-30% of the walking weight of a prey animal. Humans are not obligate carnivores, but eating the entire animal has been a mainstay of advanced hominid existence for millions of years. I find it very likely that something, someone, somewhere inside our guts is breaking down the animal fiber we eat—so you’d better be eating some!
Not so tough, is it? It’s not like I’m suggesting you load up on bran muffins, psyllium smoothies. I don’t want you dumping flax meal into everything or munching on those awful fiber gummies. Just eat some basic, healthy, low-carb plant matter—foods that don’t really scream “fiber”—and the rest will take care of itself.
What’s your favorite low-carb source of fiber? Let me know down below.
Thanks for reading, everyone.
Hernández E, Bargiela R, Diez MS, et al. Functional consequences of microbial shifts in the human gastrointestinal tract linked to antibiotic treatment and obesity. Gut Microbes. 2013;4(4):306-15.
Ukhanova M, Wang X, Baer DJ, Novotny JA, Fredborg M, Mai V. Effects of almond and pistachio consumption on gut microbiota composition in a randomised cross-over human feeding study. Br J Nutr. 2014;111(12):2146-52.
Jiao X, Wang Y, Lin Y, et al. Blueberry polyphenols extract as a potential prebiotic with anti-obesity effects on C57BL/6 J mice by modulating the gut microbiota. J Nutr Biochem. 2019;64:88-100.
Jayachandran M, Xiao J, Xu B. A Critical Review on Health Promoting Benefits of Edible Mushrooms through Gut Microbiota. Int J Mol Sci. 2017;18(9)
Nielsen ES, Garnås E, Jensen KJ, et al. Lacto-fermented sauerkraut improves symptoms in IBS patients independent of product pasteurisation – a pilot study. Food Funct. 2018;9(10):5323-5335.
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