Why Diets Fail

From Science:


Chilling out might be the key to losing the weight you gained over Thanksgiving. New research shows that dieting makes the brain more sensitive to stress and the rewards of high-fat, high-calorie treats. These brain changes last long after the diet is over and prod otherwise healthy individuals to binge eat under pressure.

Bale and her co-authors hypothesized that dieting leaves people more susceptible to the chronic stresses of everyday life, making even the strongest dieter yearn for a pint of ice cream or a hot, cheesy pizza. Although one hot fudge sundae won't cause significant weight gain, persistent stress could lead to a pattern of binge or comfort eating that undoes previous weight loss. To test their hypothesis, the researchers cut daily food intake in mice by 25% for 3 weeks, until the rodents had lost about 10% to 15% of their original body weight. This regimen simulates a moderate diet and modest weight loss in humans. After exposure to mild forms of stress, such as loud noises, the hungry mice had higher levels of cortisol in their blood. And their cortisol levels stayed higher longer than in control mice. This indicates that the dieting mice were more stressed and took more time to calm down.

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