As basic and widespread a problem as obesity seems these days, we’re still learning just what’s going on in the body to cause the condition, how the body is changed by it, and of course, how to reverse it.

We know that hormones help cue the body to experience hunger, to eat in response to those cues, and, theoretically at least, to signal us to stop us eating when we’re full. But in obese people, that system can break down with certain hormones no longer carrying out their usual roles.

Glucagon function was somehow muted in obese individuals.

One hormone, glucagon, is typically secreted when blood sugar levels start falling and triggers the body to begin releasing stored glucose. But another role it seems to play has to do with triggering feelings of fullness, and therefore counteracting the effects of another hormone — the “appetite” hormone — ghrelin.

Eleven obese people, 13 normal weight people, and 13 people with type 1 diabetes were injected with glucagon. Researchers then measured their satiety, or feelings of fullness, using self-reports and tested their blood to measure the level of ghrelin triggered in response to the glucagon injection.

Some participants received the active hormone glucagon. Others received an inert injection and served as controls.

The researchers found that feelings of fullness weren’t different in obese people who received glucagon or the control substance, suggesting that glucagon function was somehow muted in these individuals. By contrast, people of normal weight or who had type 1 diabetes did report feeling significantly fuller following the glucagon injections, and these differences were detectable even a day after the initial injections.

“Once a person becomes obese, glucagon no longer induces feelings of fullness,” said the study's lead author, Ayman M. Arafat in a news release. “Further research is needed to determine why glucagon does not suppresses appetite effectively in this population, even though they are otherwise healthy.”

The results of the study are particularly important since some weight-loss therapies currently being investigated aim to influence glucagon levels to help control the amount of food a person eats. The new study suggests that this avenue may not work so well.

“The findings could influence efforts to develop new treatments for obesity and diabetes,” Arafat said. “Although therapeutic agents that influence glucagon and other hormones currently are considered a promising avenue for research, this study suggests a treatment involving glucagon may be ineffective in controlling meal size in people who are obese.”

As we understand more about the delicate interactions of the hormones that control our eating behaviors, hopefully more effective treatments will become available. In the meantime, using the methods that are tried and true — reducing your caloric intake, eating more fruits and vegetables, exercise (after speaking with your doctor, of course), and adequate sleep — are the best bets. Some may even want to consider a plant-based diet.

The study was carried out by a team at the Charité-University Medicine in Berlin and published in the Journal of Clinical Endocrinology & Metabolism (JCEM).