Hormonal Imbalance Undermines Willpower to Maintain Weight Loss
Losing weight and keeping it off is largely a matter of balancing calorie intake versus calorie output (ie – eating right and exercising daily). But controlling what you eat can be difficult when you have a hormonal imbalance that undermines your willpower to diet. That is the conclusion from researchers at the University of Melbourne, Australia, who tested hormones involved in appetite control in a new study published in the New England Journal of Medicine.
Joseph Proietto MBBS PhD, a professor of medicine, selected 50 overweight or obese people for the 10-week study. Levels of two key appetite hormones, leptin and ghrelin, were measured before beginning a low-calorie diet (including meal replacement supplements) and after the diet was completed. The participants also had these hormones measured 62 weeks later.
Ghrelin, often called the “hunger hormone,” is secreted by the stomach and the pancreas and is released into the blood before meals and drops afterward. It acts as a natural appetite stimulant in the brain. Leptin, produced by adipose (fat) tissue, is released to suppress the appetite when enough energy has been taken in, thus controlling caloric intake.
Even a year after losing weight, the participants had increases in the ghrelin and decreases in leptin which sets the stage for weight regain. Although initially the study volunteers lost at least 10 percent of their body weight, the average weight regain was 12 pounds over the following year. “The findings explain why most people find it difficult to maintain weight loss long-term,” says Dr. Proietto. He notes that most people who have lost weight regain within five years.
While there are several medications in the works that may help to control these hormonal imbalances, the best recommendation is to prevent excess weight in the first place, says Dr. Scott Kahan to WebMD. Dr. Kahan, an obesity expert at Johns Hopkins University says, “It is not enough to throw a lot of resources at treating obesity, we need to focus on prevention.”
For those who do lose excess weight, the study re-emphasizes that a healthy diet and exercise program is not an on-again, off-again plan, but something that must be consistently maintained to prevent regain.
Proietto recommends, obviously, following a low-calorie low-fat diet and getting in at least 60 minutes of physical activity daily. When choosing a diet plan, whole grains, fruits and vegetables that are high in carbohydrate and low in fat and calories can help to suppress ghrelin levels, according to research published in 2009 by the Athens (Greece) University Medical School. Protein, from lean sources such as skinless poultry, fish and legumes, also induces prolonged ghrelin suppression, satisfying the appetite. Fat in the diet, however, produces only a weak and insufficient effect on hormone levels, thus making one hungrier again more quickly even after a meal.
A study from researchers at Loughborough University in the UK in 2008 also finds that a vigorous 60-minute workout suppresses the release of ghrelin and another appetite regulator known as peptide YY. Weight lifting can help keep ghrelin in check as well.
Sumithran P, et al "Long-term persistence of hormonal adaptations to weight loss" N Engl J Med2011; 365:1597-1604.
Broom et al. The influence of resistance and aerobic exercise on hunger, circulating levels of acylated ghrelin and peptide YY in healthy males. AJP Regulatory Integrative and Comparative Physiology, 2008; DOI: 10.1152/ajpregu.90706.2008
Chrysi Koliaki, Alexander Kokkinos, Nicholas Tentolouris, and Nicholas Katsilambros, “The Effect of Ingested Macronutrients on Postprandial Ghrelin Response: A Critical Review of Existing Literature Data,”International Journal of Peptides, vol. 2010, Article ID 710852, 9 pages, 2010. doi:10.1155/2010/710852