It’s an age-old question for dieters: Low fat or low carb? Well, they can both result in equal weight loss. But if you want to avoid biting someone’s head off, a low-fat diet might be better. People on low-fat diets aren’t as susceptible to hostility, depression and being in a bad mood as people on low-carbohydrate diets, according to an Australian study.

The study involved 106 overweight and obese adults, who successfully dieted for one year, with the help of meal plans, recipes, a supply of certain foods and regular support from a dietitian. People in both groups lost an average of 30 pounds and were pleased with this. But at the one-year mark, they were clinically assessed for anger/hostility, confusion/bewilderment and depression/dejection. The low-carb dieters fared worse on these measures.

“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,” wrote the authors in the Archives of Internal Medicine.

They guessed that low-carb diets are harder to stick to than low-fat diets because they are further removed from typical Western food habits. Perhaps that’s why they take more of a mental toll.