Your Intelligence, Damped by Low Sugar Diets

The low-carbohydrate diets like the Atkins or the South Beach Diet may let you still eat and lose a great deal of weight in a short time, but there are dangers lurking, like regaining faster weight after giving up the diet and gout. Now, another tricky effect has been found: these diets make you dumber!

A low-carbohydrate/high-fat diet and a high-carbohydrate/low-fat diet could both increase weight loss, enhance mood and speed in thinking, but the low-carbohydrate diet does not help much in terms of the speed of cognitive processes and information brain processing.

"In overweight and obese patients, following an energy-restricted dietary plan for weight loss is associated with improvements in mood, regardless of macronutrient composition," Dr Grant D. Brinkworth told Reuters.

Even if high- and low-carbohydrate diets appeared to increase the rhythm of cognitive processing, "the interesting result was that compared to the high-carbohydrate diet, subjects consuming the low-carbohydrate diet had a smaller improvement," said Brinkworth of the Commonwealth Scientific and Industrial Research Organization-Human Nutrition, in Adelaide, Australia.

His team made a comparison mood and cognitive function in overweight or obese, but mentally healthy 93 subjects, both men and women, aged 24 to 64. During a period of over 8 weeks, they followed one of two diets of equal caloric value and macronutrient composition.

The low-carbohydrate diet was made of 35 % protein, 61 % fat (20 % saturated fat) and 4 % carbohydrate. The high-carbohydrate diet was made of 24 % protein, 30 % fat (with just 8 % saturated fat) and 46 % carbohydrate.

The mood of the subjects did not appear to be influenced by the diet's carbohydrate level diet, but there was a small between-group difference, with a lower value for the high-carbohydrate dieters, in what concerns the rate at which the volunteers accomplished intelligence and reasoning tests.

It appears that "very low carbohydrate diets may offer less benefit than a high carbohydrate diet for improving cognitive function." said Brinkworth.

Further research is required in order to confirm this and to check the effects of the various diets on a longer term.