Individuals in a bad mood over their weight may want to consider switching to a low-fat diet to shed the extra pounds and improve their mental well-being, according to a new study.

The study published in the Archives of Internal Medicine found that dieters who followed a low-calorie, low-fat diet for one year had a better overall mood than those who followed a low-carbohydrate diet with the same number of calories.

Researchers studied 106 overweight and obese participants with an average age of 50. About half were assigned to follow a low-carb, high-fat diet while the others were assigned a high-carb, low-fat diet. They assessed changes in body weight, mood and well-being, and cognitive functioning periodically during the one-year study and at the conclusion.

While both groups had similar weight loss results, with an average of just over 30 pounds shed during the study, and an initial boost in mood, only the participants on the low-fat diet had a long-term improvement in mood.

"This outcome suggests that some aspects of the low-carbohydrate diet may have had detrimental effects on mood that, over the term of one year, negated any positive effects of weight loss," the authors wrote.

They said that protein and fat intake may affect brain levels of serotonin, which is a neurotransmitter related to psychological functioning. The difficulty of following a diet low in carbohydrates for an extended period of time might also have influenced mood.