Which Diet Improves Your Mood?

Dieting is tough, and requires sacrifices – not exactly steps that are likely to improve your mood.  But some may be less misery-making than others.  At a simple level, you can see how low-fat and low-carbohydrate diets compare in this respect.  There’s a study on this reported in the Archives of Internal Medicine. 

A total of 106 adults obese adults – average age 50, average body mass index (BMI) 34 – were randomly assigned to either a very-low-carb or a very-low-fat diet.  The calorie content was kept at a restricted level: 1433 – 1672 calories a day.  Body weight, psychological mood and well-being, and cognitive functioning (working memory and speed of processing) were assessed periodically during the 1-year study.

After 1 year, the participants in both groups had lost an average of 30 pounds, with no significant difference between the groups.  There were initial improvements in mood scores during the first 8 weeks, as assessed by questionnaires, with both diets.  But by the end of the study the low-carb group had scores at the original unfavorable baseline levels, while the low-fat group showed sustained improvements in depression, anger, and confusion scores.  Cognitive functioning was the same in both groups.  The average mood scores throughout were within the normal range, so the researchers stated that their findings "are limited to healthy, obese, adults with normal mood state and cannot be generalized to clinical populations."

Actually, it’s probable that successful weight loss of this magnitude increases mood regardless of the type of diet, but some aspect of the low-carb diet may have had a detrimental effect over the long term.  Maybe a low-carb diet is harder to stick to, as it contains (at least in the Western world) lots of bread and pasta.  Or maybe there’s some unknown factor in fat that, over tike, counters the subjective appreciation of losing weight.  Scientists will doubtless do more to figure this out.  In the meantime, try to eat less fat and feel better about it.