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6 Reasons Smart People Don't Diet

The research shows most dieters end up heavier or less happy.

Lucky Business/Shutterstock
Source: Lucky Business/Shutterstock

I recently published the book, Smart People Don’t Diet: How the Latest Science Can Help You Lose Weight Permanently (Da Capo-Lifelong books). As I've spoken with TV, radio, and podcast hosts, and others in the process of promoting the book, I’ve often been asked if I have ever been on a diet. I can’t lie—I have been, and I say so. I know I’m not alone; my research suggests that most men and women have at some point gone on a diet (1). We do it because we’re tempted by the promises: Lose a pound a day. Get a flat belly. Increase your metabolism. Be “thinspirational.”

What’s not to like? How about this?: These diets don’t work! When you look at the data (and, I'll bet, reflect on your own experiences), it becomes painfully obvious. Smart people just don’t diet, and here are 6 of the best reasons they don't:

  1. Dieting can make you gain weight. Here’s a little-known fact: Not only do people sometimes not lose weight when they diet; they often gain weight. In one study that tracked dieters for two years, the average person weighed more at the end of the period than at the start (2). That’s a lot of work for no reward.
  2. Dieting uses valuable brainpower. When people diet, they typically keep records of what they eat, or spend energy “counting” calories or sugar or fat grams. It turns out that this can be exhausting. In fact, dieting researchers who have examined the mental energy (often referred to as “bandwidth”) available to dieters versus nondieters have consistently found that people who diet are distracted by their diets and have a more difficult time learning new information, don’t problem-solve as well, and have lower self-control (3, 4). Ironic, isn't it? In other words, dieting reduces your mental capacity to do other, potentially more important, things.
  3. Dieting leads to ironic processing. This is probably best explained through an example. Try this exercise: What I want you to do is try not to think about chocolate at all. Don’t think about anything chocolate. OK, put all thoughts of chocolate out of your mind for the next 10 seconds—clear your mind and count to 10. How did that go? Well, if you had a hard time doing that little exercise, that means you are pretty normal. It’s ironic that when we try not to think about something we tend to think about it that much more. This is why it is so hard to not eat something we are trying not to eat.
  4. Dieting keeps you from eating “bad foods” (but some bad foods are good). Evidence suggests that if we try to eliminate all “bad foods” from our diet we are likely to end up overeating them. It's better to just allow ourselves some regular, moderate indulgences. In fact, in one study, when people were allowed to eat a little something sweet each day, they were more likely to lose weight and keep it off, than a comparison group that abstained from sweets altogether (5).
  5. Dieting leads to binging. Researchers actually refer to this as the “What the Hell?" phenomenon (6). It turns out that when we go on a diet—and inevitably pledge to avoid certain foods such as carbs, sweets, or fat—we typically slip and tend to think, "What the Hell?" Then, instead of eating just one dessert, we have three. And instead of eating one doughnut, we take four. After all, we think, we’ll just start our diet again on Monday. But the interim binging is likely to contribute to weight gain, guilt, and even disgust with ourselves. It’d be better for our psyche—and our waistlines—to just take one dessert from the start.
  6. Every time you fail on a diet you make someone else money. One thing that scientists who study weight management know without question is that the diet industry is delighted when we fail on our diets—because we’re likely to try again and that just makes them more money! Imagine if the first diet you tried worked: The multibillion-dollar industry would disappear.

I’ll say it one last time: Smart People Don’t Diet. And, it is never too late to become smart.

Smart People Don’t Diet (Da Capo Lifelong Books and Nero) by Dr. Charlotte Markey is available now, wherever books are sold. You can follow me on Twitter (@char_markey), Facebook (Dr. Charlotte Markey), Pinterest (Dr. Charlotte Markey) and on my website.


1) Markey, C. N., Markey, P. M., & Birch, L. L. (2001). Interpersonal predictors of dieting practices among married couples. Journal of Family Psychology, 15, 464-475. doi:10.1037//0893-3200.15.3.464.

2) French, S. A., Jeffery, R. W., Forster, J. L., McGovern, P. G., Kelder, S. J., & Baxter, J. (1994). Predictors of weight change over two years among a population of working adults: The Healthy Worker Project. International Journal of Obesity, 18, 145–154.

3) Mata, J., Todd, P. M., & Lippke, S. (2010). When weight management lasts: Lower perceived rule complexity increases adherence. Appetite, 54, 37–43.

4) Dax, U., Peter, C., & Polivy, J. (2002) Eat, drink and be merry for tomorrow we diet: Effects of anticipated deprivation on food intake in restrained and unrestrained eaters. Journal of Abnormal Psychology, 111, 396–401.

5) Jakubowicz, D., Froy, O., Wainstein, J., & Boaz, M. (2012). Meal timing and consumption influence ghrelin levels, appetite scores and weight loss maintenance in overweight and obese adults. Steroids, 10, 323–331.

6) Polivy, J., & Herman, C. P. (1985). Dieting and bingeing: A causal analysis. American Psychologist, 40, 193–201.

@Copyright Charlotte Markey 2015