Journal Watch: Hormonal Forces Drive Excess Body Weight
Information sourced from Journal Watch:
Swimming Against the Current: Hormonal Forces Drive Excess Body Weight
Hormones that regulate hunger and energy storage make it hard for overweight people to lose weight.
Many of us were taught, and still believe, that being overweight or obese results from lack of discipline about diet and exercise. However, during the past 20 years, a group of hormones produced by adipose tissue and the gut have been shown to affect appetite and energy metabolism.
An Australian team enrolled 50 overweight or obese participants without diabetes in a severe caloric-restriction program. The program lasted 10 weeks and led to an average weight loss of 14%. Thereafter, participants were given individualized instructions on caloric intake and exercise needed to maintain weight loss. At 62 weeks, participants had regained a mean of about half their lost weight.
Caloric restriction and weight loss were associated with dramatic increases in hormones (such as ghrelin), which increase appetite and energy storage, and with dramatic decreases in multiple hormones that encourage satiety and promote energy expenditure (such as leptin). Even those participants who remained very overweight after the weight-loss program experienced strong hormonal urges to eat more and to burn less energy.
Comment: Ubiquitous fast food and lack of exercise profoundly influence obesity. Although limited by its relatively small size and high attrition rate, this study suggests that a biological component also might be present. People who are overweight are constantly in a hormonal environment that makes them hungry and causes them to burn less energy during exercise. Trying to lose weight through diet and exercise feels like swimming against the current.
Anthony L. Komaroff, MD
Published in Journal Watch General Medicine October 27, 2011
Sumithran P et al. Long-term persistence of hormonal adaptations to weight loss. N Engl J Med 2011 Oct 27; 365:1597. [Medline ® Abstract]