Weight loss undone by appetite hormones
31 October 2011
People with obesity who pile the kilos back on after a period of successful weight loss are probably not just being slack in their habits, they are victims of a surge of hormones that encourage weight gain, researchers say (New England Journal of Medicine 2011; 365:1597-604).
Australian obesity expert Professor Joe Proietto, from the University of Melbourne and Austin Health, has demonstrated the role of appetite-regulating hormones in undermining attempts to maintain initial weight loss in people with high BMI (body mass index) who have dieted successfully.
It is already known that weight loss causes changes in the levels of hormones involved in regulating body weight - slowing metabolism, increasing appetite and encouraging weight gain. This study examined whether these changes persist over time.
Fifty overweight or obese adults (BMI 27-40 kg/m²) undertook a weight loss program involving replacement of meals with a very low energy commercial dietary formulation plus low-starch vegetables over 8 weeks. Thirty-five stayed on the program, with an average weight loss of 13 kg, and were followed up over a year.
A year after the initial weight loss, key hormones which encourage weight regain had not reverted to their pre-diet levels. This meant the former dieters' bodies were under hormonal pressure to eat more, conserve energy and store fat.
Hormones measured included leptin and ghrelin. Leptin, which suppresses appetite, decreased during dieting and rose in tandem with bodyweight after the weight loss program finished, while ghrelin, which stimulates hunger, rose significantly with weight loss and persisted at a high level for up to 12 months.
"[This] suggested that the high rate of relapse among obese people who have lost weight has a strong physiological basis and is not simply the result of the voluntary resumption of old habits," the authors wrote.
Last Reviewed: 31 October 2011
- 1. Sumithran P, Prendergast LA, Delbridge E, et al. Long-term persistence of hormonal adaptations to weight loss. N Engl J Med 2011; 365: 1597-604. http://www.nejm.org/doi/full/10.1056/NEJMoa1105816 (accessed Oct 2011).
