SAN FRANCISCO—When a person loses weight, stress levels increase, and it’s not only because of the preoccupation with reducing calories. An article posted on USA Today by Nanci Hellmich said new study (Psychosom Med. 2010 Apr 5) found a physical reason for greater stress while dieting: increased cortisol levels.
The study, conducted researchers at the University of California-San Francisco, found restricted-calorie diets increase the stress hormone cortisol in women. Close to 100 women who were randomly assigned to one of four eating groups. The first group was taught to follow a diet of 1,200 calories a day, and was instructed to track caloric intake. The second group also keep their intake to 1,200 calories a day, but ate pre-packaged food and were not asked to track calories. The third group did not restrict their diets, but counted calories; and the fourth group did not restrict or count calories. The women completed surveys on their stress levels before and after the diets and also gave saliva samples to test their bodies’ level of cortisol.
After three weeks, the women on the 1,200 calorie diets lost an average of 2 pounds, while the non-dieters gained an average of 2.5 pounds. However, those on the restricted diet had higher levels of cortisol than before the study and than those who did not diet.
Researchers noted increased chronic psychological stress and cortisol production are two factors are known to cause weight gain. They concluded, “Dieting may be deleterious to psychological well-being and biological functioning, and changes in clinical recommendations may be in order.”
In the USA Today article, lead author Janet Tomiyama is quoted as recommending implementing stress-reducing activities while dieting, or skipping the diet all together and exercising more instead.
