Diets Are a Drag but Low-Fat Diets Can Boost Your Mood

Nov. 10, 2009— -- Research has shown that shedding pounds tends to put people in a good mood, but a new study finds that if they're cutting back on carbohydrates, these good vibes may be short-lived.

An Australian research team assessed changes in mood for dieters on either a low-fat or low-carbohydrate diet, and found that throughout a year of dieting, a low-fat plan improved overall feelings of well-being.

The low-carb diet on the other hand, had the same mood-boosting effect at first, but this change in mood began to wear off after the first few weeks.

"This outcome suggests that some aspects of the low-carbohydrate diet may have had detrimental effects on mood that ... negated any positive [mood] effects of weight loss," the authors write.

The study, which was published this week in the Archives of Internal Medicine, is the first to look at emotional differences long-term between these two diets.

Researchers had 106 participants follow a reduced calorie diet, but randomly assigned participants to a regimen that was higher in fat and very low in carbohydrates or one that allowed carbohydrates but with cutbacks on the amount of fat.

Participants met with a dietician twice a month to help them stay on track and researchers assessed participants' feelings of depression, anxiety, anger, and fatigue before the diet began, after eight weeks of dieting, 24 weeks, and at the end of the year.

Though participants consumed the same amount of calories and lost the same amount of weight -- 30 pounds on average -- only those on the low-fat diet maintained an increase in positive mood throughout the year.

"I'm not surprised at all that [dieters] would have a better mood while [still] eating healthy carbs," says Dr. Keith Ayoob, nutritionist and associate professor at Albert Einstein College of Medicine in New York. "When a diet is [very] low in carbs, it can start to wear you down."