Low-carb vs. mental functions

Low carbohydrate diets are, no doubt, an effective tool in the work on excessive body weight reduction. In recent years there have been many studies showing that, contrary to some concerns, such solution is relatively safe for health. However, this does not mean that being on this diet is totally safe. There are theories saying that limiting carbohydrate intake adversely affects mental functions. It is worth considering whether this statement is true.

Your brain needs glucose

Your brain cells need glucose; this fact cannot be argued. As a matter of fact, some of these cells can switch to other fuel, more specifically ketones obtained from lipids' transformation during sugar shortages, however, some parts of the brain do not have such skills. With this fact in mind, there are concerns about whether diets, which intentionally restrict carbohydrate intake, significantly impair brain functioning. Well, you certainly should not fear any major disturbances; your body is able to produce glucose itself from glycerol, amino acids and lactate. However, some minor troubles may arise, or at least this is what scientific literature predicates.

An interesting experiment

Tufts University research has provided pretty interesting data in this matter. 19 women were involved in the study. One group used a diet which was low in carbohydrates, the other: varied, calorie-low, recommended by the American Dietetic Association. Before starting the diets, and also several times in the course of their duration, the ladies took part in a special test which was to assess their concentration, memory and perception, and evaluate subjective feeling of hunger and mood during the experiment.

What was the result?

First the good news: the group of women on the low-carb diet noted better well-being and faster response time. So you could say that contrary to popular opinions, restrictions of carbohydrates need not worsen your mood nor undermine your reflex. This study has shown it is exactly the opposite. The bad news is that in ladies on the low-carb type of diet their memory significantly deteriorated. The differences between the members assigned to each group were significant when it comes to this aspect.

To sum up

Based on the data from this study you may arrive at the conclusion that a low carb diet is not the best solution in a period when you have to absorb large amount of knowledge (e.g. before the exam, in the course of intensive study). On the other hand, the study of the above restrictions, carbohydrates proved to improve mood and reflexes. A separate issue is the fact that the mentioned study has been carried out on a small group of persons of one sex over a short period of time. The results should be treated as a curiosity rather than a revelation of truth.


Sources: D'Anci KE1, Watts KL, Kanarek RB, Taylor HA. Low-carbohydrate weight-loss diets. Effects on cognition and mood. Appetite. 2009 Feb;52(1):96-103.