Why Eating Less Doesn’t Always Work

Off the bat, I should say that I’m actually a fan of eating less. I’m on record as saying that my goal is to figure out how few calories I can eat and still thrive. Still, eating less isn’t always the magic bullet people will hope it will be. There are many ways that eating less can go wrong.

For weight loss, the advice to “eat less, exercise more” often doesn’t work like it “should” on paper. The weight-loss diet industry thrives on repeat customers who struggle to lose weight and keep it off. Dutifully following this strategy has led many people down the road to frustration and dejection, as they blame themselves for their failure to successfully lose weight. This is despite their best efforts to eat less.

From a health perspective, eating less is a double-edged sword. On the one hand, caloric restriction may promote longevity. It certainly does in many animal models. Human evidence is still mixed, but I’m betting that the same is true for us.https://pubmed.ncbi.nlm.nih.gov/21677272/‘>² It tries to tightly ration body fat in case you’re facing a prolonged food shortage.

Let’s back up. The “energy out” side of the energy balance equation comprises several factors:

• Basal metabolic rate – the energy your body expends in the everyday functions of being alive (breathing, circulation, generating new cells, etc.)https://www.sciencedirect.com/science/article/pii/S155041311830130X‘>⁴ It’s not so great when it comes to weight loss.

  Moreover, the body responds to caloric restriction by dialing back activity. “Non-exercise activity thermogenesis,” or NEAT, is the term for the energy you expend through spontaneous movements like tapping your feet or nodding your head along to music. NEAT can vary up to 2000 calories per day between individuals.https://pubmed.ncbi.nlm.nih.gov/17197279/’>⁶ and when they are dieticians.https://pubmed.ncbi.nlm.nih.gov/21178922/‘>⁸ Another small study showed that individuals who were struggling to lose weight underreported their caloric intake by 47 percent and overestimated energy expended by 51 percent, on average.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5491979/‘>¹⁰)

  Even if you’re diligently weighing and tracking your food, you’ll probably be off through no fault of your own. The FDA allows a margin of error of up to 20 percent for calories reported on food labels.https://pubmed.ncbi.nlm.nih.gov/20102837/‘>¹² https://academic.oup.com/jcem/article/82/11/3647/2865985‘>¹⁴ In fact, it drops more than would be predicted by body composition alone.https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3296868/‘>¹⁶ loss of libido, and infertility.https://academic.oup.com/jcem/article/91/8/3232/2656790‘>¹⁸ That said, you can definitely have too much of a good thing. You don’t want to restrict calories to the point where you start experiencing symptoms of hypothyroid such as feeling cold all the time, unexplained weight gain, or fatigue.

  When It’s Stressful

  I’ve said it a million times: stress is the enemy of health and weight loss. As with so many things in life, calorie restriction can be an adaptive (hormetic) or maladaptive stressor. It all depends on how it’s applied and how your body reacts.

  Restricting calories increases cortisol, aka “the stress hormone.”https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5813183/‘>²⁰—and who subsequently struggle to eat enough. If they aren’t mindful, they can easily under-eat to the point they are getting enough nutrients.

  If you suspect you might be under-eating, use an app like Cronometer to track your food for a few days. Make sure you are checking the nutritional boxes you need to stay healthy.https://pubmed.ncbi.nlm.nih.gov/18589032/‘>²² https://pubmed.ncbi.nlm.nih.gov/23446962/‘>²⁴ Your calorie deficit should come from reducing fat and/or carbs, depending on your current diet.

  What about Metabolic Damage?

  Dieting forums are filled with dire warnings against dieting so long or so hard that you go into “starvation mode” and create permanent “metabolic damage.”

  You might be familiar with the highly publicized Biggest Loser study, which followed contestants from the televised weight loss competition.https://pubmed.ncbi.nlm.nih.gov/6694559/‘>²⁶ https://pubmed.ncbi.nlm.nih.gov/22535969/‘>²⁸

  Whether this constitutes permanent metabolic damage is a hotly debated topic. A recent paper called the notion into question. https://pubmed.ncbi.nlm.nih.gov/15466943/
  ‘>³⁰. It helps keep your metabolic rate up by protecting energy-guzzling muscles and organs. Protein also has a higher thermic effect than fat or carbs, further contributing to metabolic rate.