A new drug that combats “the munchies” could provide a long-lasting solution to weight loss, say researchers.
The drug, known only as JD5037, increases sensitivity to a natural hormone in the body that suppresses appetite.
It acts by blocking the same brain pathways responsible for feelings of hunger after taking cannabis.
But, crucially, it does not penetrate far enough into the brain to cause psychiatric problems.
A similar anti-obesity drug, rimonabant, had to be withdrawn after it was linked to anxiety, depression and suicidal thoughts.
JD5037 affects the way the body reacts to leptin, a hormone that promotes feelings of satiety, or "fullness".
Attempts to boost leptin levels have failed because the body becomes desensitised to the hormone and stops responding to it.
JD5037 does not increase levels of leptin, but enhances its effect.
"By sensitising the body to naturally occurring leptin, the new drug could not only promote weight loss, but also help to maintain it," said lead scientist Dr George Kunos, from the National Institute on Alcohol Abuse and Alcoholism in the US.
"This finding bodes well for the development of a new class of compounds for the treatment of obesity and its metabolic consequences." The research, reported in the journal Cell Metabolism, was conducted on overfed obese mice.
Scientists found that giving the mice the drug caused weight loss and improved metabolic health. The animals showed no signs of anxiety or other behavioural side-effects.
Dr Kunos added: "Obesity is a growing public health problem, and there is a strong need for new types of medications to treat obesity and its serious metabolic implications, including diabetes and fatty liver disease."