Weight loss and gain correspond to the way the brain overcomes stress and hunger.
The yo-yo effect is so strong that it can alter the DNA structure of the stress-regulating hormone corticosterone , according to a new study published in the journal Neuroscience.
Scientists study the level of stress hormone in a restricted diet.
Comparing the results of a normal diet, the researchers found that in three weeks the diet lost between 10 and 15% of weight.
In addition to weight loss, high levels of corticosterone and increased depression have been reported.
The study also shows a change in the structure of genes important for regulating stress and hunger. The effect is due to a change in the shape and structure of DNA known as epigenetics .
Epigenetic changes are irreversible even after a return to the diet, experts explain.
Diets not only increase stress, but can also readjust the brain's actions to future stressful situations and diets, says Dr. Tracy Bale, team leader at the University of Pennsylvania.
Regulating stress during a diet is critical to achieving a positive end result, said Dr. Jeffrey Sigman, an expert in endocrinology, diabetes and metabolism at the University of Texas Southwestern Medical Center.