Why diets make you fat

Fork and spoon with chain isolated on white

If your diet doesn’t work, you’re to blame. You’ve either picked the wrong diet, or you don’t have the willpower. Well, so you’re led to believe.

After all, you’ve seen those ‘before’ and ‘after’ photos, heard testimonials from slimmer-than-ever celebrities, maybe even seen your friends whittle themselves down two or three dress sizes.

But we’re rarely told how long the weight loss lasts. And there’s a reason for that. Time and again, weight that’s been lost is regained. Just ask Oprah!

In May 2015 the journal Obesity published a study that shed light on why it can be so hard to keep lost weight off for good. The research subjects were well known to many. They were the contestants from season eight of the US Biggest Loser.

The participants’ measurements – body weight, fat, metabolism, and hormones – were taken at the end of the season and again six years later. By the end of the six years, 13 out of 14 contestants had regained a significant amount of weight, with four heavier than they were before the show. This is despite continuing to exercise regularly and eat healthily.

The most remarkable finding, however, was that the basal metabolic rate (BMR) of all the participants had vastly slowed down over the six year period. Many were burning about 500 calories (2000 kilojoules) fewer a day than would be expected. That’s the equivalent of a meal per day.

This doesn’t surprise neuroscientist Sandra Aamodt, author of Why Diets Make Us Fat: The Unintended Consequences of Our Obsession With Weight Loss.

“The root of the problem is not willpower, but neuroscience,” says Aamodt. Suppression of your BMR is just one of several tools the brain engages to keep your body within a certain weight range, called the set point. When your weight drops below this, you’ll burn fewer calories in an effort to prevent further weight loss. Now this was a useful mechanism when we lived in times of famine, but a cruel irony for those on a weight loss diet.

This might explain why studies show that dieters are more likely than non-dieters to become obese over the next one to 15 years. This effect is strongest in those who started in the normal weight range, a group that includes almost half the female dieters in the US.

How else does dieting lead to weight gain?

  1. “You’re more likely to notice food,” says Traci Mann, author of Secrets from the Eating Lab. Mann teaches psychology at the University of Minnesota, and has studied eating habits, self-control and dieting for more than 20 years. “Your brain takes over. It thinks you’re starving and becomes overly responsive to tasty looking food. The thing you’re trying to resist becomes harder to resist.”
  2. As you lose body fat, the amount of different hormones in your body changes, says Mann. Those that help you feel full decrease, while those that make you feel hungry increase. The end result is that you’re more likely to notice food, more likely to feel hungry, and less likely to feel full given the same amount of food. How unfair is that?
  3. “Dieting is stressful,” says Aamodt. Too true. But this actually has a physiological effect. Restricting food intake and feeling hungry produces stress hormones including cortisol, which act on fat cells to increase the amount of abdominal fat.
  4. Weight anxiety and dieting can lead to later binge eating as well as weight gain, according to Aamodt. One study found that adolescent girls who dieted frequently were 12 times more likely than non-dieters to binge two years later. In animal studies, binge eating is a common response to starvation.
  5. Dieting forces you to use external rules rather than internal hunger cues to control eating, explains Aamodt. Eating this way eventually makes you more vulnerable to external cues telling you what to eat, such as advertising, supersizing, and all-you-can-eat buffets. Willpower will quickly take a back seat in the face of these pressures.

What’s the alternative?

Rethinking the dieting approach can take time and effort. But it’s worth it to finally have a healthy relationship with food and lose the guilt around eating the ‘wrong’ foods.

Pay attention. Mindful is the new buzzword around food and eating. Mindful eating means paying attention to the food, its taste and texture, and to your signals of hunger and fullness. Over time you can relearn how to eat only as much as your brain’s weight-regulation system tells you.

The opposite of course is mindless eating. This happens when we’re focused on something other than the food, such as when eating popcorn at the movies or chocolate in front of the TV. The end result? We eat more of less healthy food.

Make it harder. And if you really don’t trust yourself around tempting food, put up a barrier between you and it. Mann argues that humans are naturally lazy. Any obstacle will slow us down, if not stop us entirely. So move that packet of biscuits out of sight or just that bit further away – if you have to get up and walk to reach them, you’re going to eat less. Remove them from the house entirely if you need a greater obstacle.

Give yourself permission to eat all foods. This can be empowering and lessen the temptation of treat foods. Many people report actually eating less of tempting foods and not bingeing if they are permitted to eat them. After all, life’s too short to never eat cake.

Sick of dieting and want to try another way? Get in touch with me on 0411 095 871 or jenny@jennybossnutrition.com.au for an obligation free 10-minute chat about your circumstances and the approach that would best suit you.