Some individuals who lose weight by restricting their calories can have trouble keeping the pounds off once they resume typical eating, and a recent study may have determined one reason why.

A paper printed in the Journal of Clinical Endocrinology and Metabolism has established that individuals with low levels of ghrelin and high levels of leptin may experience weight gain after dieting.

The study contradicts previous research that determined low leptin levels contribute to weight gain in individuals who are overweight or obese.

Ghrelin is a hormone secreted by the stomach lining that contributes to hunger, while leptin crates a sense of fullness or satiety.

The study’s authors concluded that people with imbalanced levels of leptin and ghrelin are at risk for gaining back at least 10 percent of any weight previously lost. They added that this phenomenon may be a part of “yo-yo dieting,” in which individuals’ weight can fluctuate repeatedly.

Similar studies have found that obese men may release lower amounts of leptin when eating even the heaviest of meals.