Low-carbohydrate weight-loss diets are associated with poor cognitive performance.

This study investigated the effect of low-carbohydrate diets on mood and cognitive performance. Researchers divided the participants in this study into two groups. One group was fed with self-selected low-carb diets and the American Dietetic Association (ADA) recommended reduced-calorie "balanced diet" was given to the second group. The profile of mood scale (POMS), vigiliance attention, visuospatial memory, and memory span were assessed in all the subjects during the feeding period.

Researchers found out that the low-carb group performed better in attention vigilance tasks and reported less confusion than the ADA group did. On the other hand, low carb dieters performed poorly in memory-based tasks when dietary carbs were completely withdrawn compared to the ADA group. Significant improvements in memory-based tasks were observed in low-carb dieters when carbohydrates were re-introduced into their diet. The results of this study show that low-carbohydrate weight-loss diets may have negative effects on cognitive performance.