Dieting is hailed as one of the most effective ways to lose weight, though many dieters struggle to keep the weight off long term. Now, researchers say there may be a more effective alternative: brain injections of an appetite-suppressing gene.

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Researchers say leptin gene therapy may be more effective than dieting for long-term weight loss.

In a new study published in the Journal of Endocrinology, researchers describe how injecting a gene into the brain that codes for the hormone leptin may curb overeating, leading to long-term weight loss.

Leptin is a hormone secreted by adipose cells, or fat cells, that plays a role in regulating energy balance by curbing hunger. Often referred to as the “satiety hormone,” leptin works by sending signals to the brain that tell us when to stop eating.

The amount of leptin released by fat cells is dependent on the amount of body fat a person has; the greater the amount of body fat, the more leptin that circulates in the blood. People who are obese have very high leptin levels, but their brain often stops responding to the hormone as a result, causing them to overeat.

While dieting and exercise are often the first port of call for people who want to lose weight, study author Dr. Urszula Iwaniec, of Oregon State University, and colleagues note that such strategies often fail to have prolonged success.

“Unfortunately, the long-term efficacy of conventional weight loss interventions is generally poor and many individuals weight-cycle through repetitive bouts of weight loss followed by rapid weight regain,” they note.

They add that repetitive weight loss and weight gain can take its toll on bone health, raising the risk for osteoporosis – a disease in which the bones become weak, increasing fracture risk.

“Because osteoporotic fractures are associated with decreased quality of life and increased mortality, there is strong incentive to develop weight loss strategies that preserve bone mass,” say the authors.

For their study, the team set out to determine whether leptin gene therapy could be one such strategy.

The researchers injected the brains of seven adult female rats with a recombinant adeno-associated virus that encoded the gene for rat leptin, called rAAV-Leptin.

The results were compared with two control groups of rats; one group was injected with a recombinant adeno-associated virus called rAAV-GFP, while the other group received no injection.

All rats were weighed at the beginning of the study and 18 weeks after, and their food intake was monitored weekly. The researchers also assessed the rats’ bone mass at study end.

While the mice that received rAAV-GFP gained weight, those that received the leptin gene therapy consumed less food, lost weight and were able to maintain their lower body weight over the 18-week study period. In addition, the team found the mice that received the leptin gene therapy did not lose bone mass.

Though further research is warranted to determine whether leptin gene therapy would be safe and effective for humans, the team believes their findings suggest it may be a promising strategy against obesity – one that does not have negative implications for bone health.

Dr. Iwaniec says:

In this study we show that leptin gene therapy causes effective long-term weight loss while maintaining bone mass. Novel approaches like leptin gene therapy for treating obesity are needed to address this public health crisis.”

In the US, almost 35% of adults – or 78.6 million Americans – are obese, increasing their risk for heart disease, stroke, type 2 diabetes and some forms of cancer.

In August, Medical News Today reported on a study in which researchers discovered a direct link between a specific gene and fat production in the body – a finding that may pave the way for a new treatment for obesity.