We’ve all gone through the cycle – you start a diet, you’re very committed to it, you enjoy some results, and then you drop it, only to put on the weight you loss and then some extra. New research suggests that yo-yo dieting might have a strongly neurological component, and leads to more weight gain in the long term.
The research, conducted by the universities of Exeter and Bristol in the UK, suggests that yo-yo dieting trains the brain to interpret caloric deficits as periods of famine, and primes the body to store additional fat when the food intake increases again. It explains why the urges to binge eat following a diet are so strong, and why people have such a difficult time managing their weight through drastic interventions like dieting.
Individuals who do not go through dieting cycles, if the research is to be believed, are more homeostatic. Their bodies are not keyed up to manage intermittent periods of undernourishment and consequently store less fat from food.
The study, which was published in Evolution, Medicine and Public Health, observed this phenomenon in animals, especially birds. Birds are, typically, fatter during colder months. This is because their bodies store more fat to cope with the paucity of seeds and insects during the winter.
The researchers even implemented a mathematical model that describes the relationship between food abundance and fat storage. One of the scientists involved, Dr. Andrew Higginson, said, “Surprisingly, our model predicts that the average weight gain for dieters will actually be greater than those who never diet. … This happens because non-dieters learn that the food supply is reliable so there is less need for the insurance of fat stores.”
And according to the study, even post-diet bingeing won’t slate the increased appetite for calories, since the body is working to prepare for more famines. Professor John McNamara of the University of Bristol’s School of Mathematics says, “Our simple model shows that weight gain does not mean that people’s physiology is malfunctioning or that they are being or that they are being overwhelmed by unnaturally sweet tastes. The brain could be functioning perfectly, but uncertainty about the food supply triggers the evolved response to gain weight.”
According to Dr. Higginson, “The best thing for weight loss is to take it steady. Our work suggests that eating only slightly less than you should, all the time, and doing physical exercise is much more likely to help you reach a healthy weight than going on low-calorie diets.”