Obesity May Be Tied to Brain-activated Cravings for Food

Obesity May Be Tied to Brain-activated Cravings for Food

Researchers at Imperial College London are investigating if hormones normally produced in the gut could reduce cravings for high-fat and high-sugar foods, as well as for alcohol and cigarettes.

Studies showed that people who are overweight can experience cravings identical to people addicted to alcohol, nicotine, or other drugs. Researchers hypothesized that certain brain areas linked to cravings may be over-activated when overweight people come into contact with food.

Two hormone systems — ghrelin and glucagon-like peptide-1 (GLP-1) — that play an important role in regulating appetite have recently been shown to target areas in the brain involved in addiction, stress, and reward. Interestingly, these are the same brain areas involved in cravings.

Considering this, the research team wanted to explore whether compounds that mimic these hormones could help reduce cravings for food, cigarettes, and alcohol. The team is now looking for volunteers to participate in the study.

In a press release, one of the study leaders, Dr. Tony Goldstone, said, “Studies suggest that people who are overweight may also respond to stress by over-eating, or be more impulsive. These behaviors will predispose them to overeat, particularly foods high in fat and sugar. They may also find it difficult to stop eating when they are trying to lose weight — in much the same way that people find it hard to give up cigarettes when they are quitting smoking, or giving up alcohol when they have a drinking problem.”

The team will enroll a total of 90 adult participants: 30 people who are overweight and trying to lose weight, 30 smokers who have recently stopped, and 30 recent former alcohol drinkers. After three infusions of hormones similar to GLP-1 and ghrelin, or placebo infusions, researchers will test participants’ craving levels.

The study will employ brain scans to measure brain activity in the areas associated with cravings while the study’s participants are viewing images of food — particularly high-fat or high-sugar food — or of cigarettes and alcohol.

Researchers will also investigate whether the hormones can reduce activity in stress-related brain areas by exposing the volunteers to mildly stressful pictures, such as images of people holding knives or guns, while measuring their brain activity. The researchers hope that the hormones may help people avoid giving in to the urge to eat, drink, or smoke while under stress.

If successful, the study could lead to future drug treatments for addiction, Dr. Goldstone said in the release.

“Obesity, smoking, and alcohol dependence are major health burdens to society. In obesity, nonsurgical interventions, such as diet and exercise programs, have been disappointing in achieving long-term weight loss. Similarly with alcohol and smoking dependence, relapse is common when trying to quit. Therefore, there is a pressing need to develop new drug treatments for addiction,” he said. “We hope this study may lead to these. Such a new hormonal approach may also have the added benefit of helping to prevent weight gain after people quit smoking. This is a common reason why people either do not want to stop smoking in the first place, or start smoking once again after they have given up.”

More information on this study, being conducted at Hammersmith Hospital in London, is available through this link.

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