SHAFAQNA- Our ancestors may be the reason why yo-yo diets do not work on us, if this latest research is anything to go by.
A study by the University of Exeter suggests cyclical dieting triggers the “caveman response” – a survival mechanism hard-wired by evolution which causes the brain to interpret repeated diets as periods of food scarcity.
It appears when we are between diets, our brain sends out signals telling the body to store more fat in case of future shortages.
However the study, published in the journal Evolution, Medicine and Public Health, is based on observations of nature rather than humans.
To test the theory, scientists constructed a mathematical model to investigate the phenomenon in a simulated animal that does not know when to expect its next meal.
It showed that during times of scarcity, an animal that grabs the opportunity to put on weight has the best chance of passing on its genes.
Lead researcher Dr Andrew Higginson believes the same model could apply to humans.
He 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.”
Humans evolved in a harsh environment where food supplies could be abundant one moment and gone the next. In that situation, those with the ability to store more fat would have a survival advantage.
While food shortage may not be a problem anymore – at least in first-world countries, scientists say the human body still mimics the “caveman response” when people resort to yo-yo diets, resulting in a vicious circle of weight gain and severe calorie cutting.
“The best thing for weight loss is to take it steady,” said Higginson. “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.”