The worldwide rates of obesity are increasing daily. Though a low-calorie diet does help reduce weight, the weight that’s lost is often regained once the regular diet is resumed. Various hormones control this regain of weight. In this current study, researchers studied the role of three important hormones that regulate food intake: leptin, ghrelin and insulin. The study found that people with high levels of leptin and low levels of ghrelin in their blood were more prone to regaining weight.
The main objective of this study was to investigate whether hormone levels of leptin and ghrelin influence regain of weight after slimming. Evidence indicates that often a slimming regimen can fail over the long term because the body’s metabolism works against dietary restrictions. The study aimed at investigating whether measuring blood levels of leptin, ghrelin and insulin would help identify people at risk of regaining their weight after a low-calorie diet was stopped. This would help enhance the treatment of obesity, which in turn would help to reduce the complications associated with obesity, such as diabetes mellitus and cardiac diseases.
- • A total of 104 obese or overweight volunteers (Body Mass Index of more than 30) were included in the study, out of which 49 were women and 55 were men.
- • A diet which contained 30 percent less calories than required was given to all volunteers for a period of eight weeks. Loss of weight was measured after eight weeks of low calorie diet treatment.
- • For the next six months, they were asked to follow general dietary guidelines, along with adequate physical activity.
- • The weight of the volunteers was measured at the start of the study, after eight weeks and after six months. At the same time, blood levels of hormones leptin, ghrelin, and insulin were measured.
- The average weight loss after eight weeks of strict calorie restriction was 5 percent of the body weight.
- As a result of this diet therapy, there was a decrease in the levels of leptin and insulin; however, the level of ghrelin was not altered.
- In the next six months, 55 people (25 women and 30 men) maintained their weight while 49 people (24 women and 25 men) regained their weight (i.e. a minimum of 10 percent of lost weight).
- Among people who regained their weight, high levels of leptin and low levels of ghrelin were found. Insulin levels did not change significantly.
One of the shortcomings of this study was that the levels of hormones were assessed only at one time during an entire day. It is well-known that these hormone levels change significantly at different times in the day and also vary with food intake. Further studies which will take such variations in hormone levels into account are necessary.
The study identified people who gained back at least 10 percent of their lost body weight, six months after the low calorie diet. These people had raised fasting leptin levels and lowered fasting ghrelin levels, compared to those who had maintained their reduced weight. People with higher levels of leptin and low levels of ghrelin in blood are at higher risk of redeveloping obesity after treatment. The study also found that the response to treatment and diet depended on gender. So assessment of levels of these hormones would be helpful in predicting the risk of regaining of weight after successful treatment of obesity.
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Publication Journal: The Journal of Clinical Endocrinology & Metabolism, August 2010
By Ana B Crujeiras; Estibaliz Goyenechea; Complejo Hospitalario de Santiago and Santiago de Compostela University, Santiago de Compostela, Spain and University of Navarra, Pamplona, Spain