The levels of hormones that control hunger and fullness(satiety) both rise after weight loss, but individuals may only experience an increase in hunger, according to a new study. The study is published ahead of print in the American Journal of Physiology -- Endocrinology and Metabolism.

A team of researchers studied adult volunteers with severe obesity (body mass index greater than 40) who participated in a comprehensive weight loss program. The volunteers attended five sessions at a multidisciplinary rehabilitation program over the course of two years. During each three-week residential session, participants learned about interventions to aid weight loss, including eating a balanced, calorie-restricted diet, physical activity, talk therapy and nutrition education. Between program visits, participants were encouraged to continue with daily exercise and a healthy diet at home. The research team measured hunger and satiety hormone levels in the blood after the first four weeks of the trial and again after one and two years of continued weight loss. Investigators also recorded the participants' self-reported feelings of hunger and fullness at each of these intervals.

After one month of following the program, the volunteers' subjective sense of fullness after a meal was unchanged, but decreased at the one- and two-year marks, whereas self-reported hunger increased significantly after one and two years. The research team found increases in the levels of both the hunger and satiety hormones after one and two years of sustained weight loss. However, the boost in hunger hormones seemed to override the increase in satiety hormones, explained the researchers.

"This information is of importance for patients and health professionals working with this patient group, and strategies should be identified that can help patients deal with increased hunger in the long term," the researchers wrote.