High-carb diet may boost brain

Last updated: Monday, October 01, 2007 Print

Followers of low-carb diets such as the Atkins or the South Beach Diet may be paying an unexpected price: they could be sacrificing some speed at which their brains process information.

"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 Health.

But the low-carb diet may offer less benefit in terms of the rate of cognitive processing.

"The interesting result was that compared to the high-carbohydrate diet, subjects consuming the low-carbohydrate diet had a smaller improvement," Brinkworth noted.

How the study was conducted
Brinkworth, of the Commonwealth Scientific and Industrial Research Organisation-Human Nutrition, in Adelaide, Australia, and colleagues compared mood and cognitive function in overweight or obese, but otherwise healthy, men and women who were between 24 and 64 years old.

Over eight weeks, participants followed one of two diets of similar caloric and macronutrient content, the researchers report in the American Journal of Clinical Nutrition.

The low-carbohydrate diet contained 35 percent total protein, 61 percent total fat (20 percent saturated fat) and 4 percent total carbohydrate. The high-carbohydrate diet consisted of 24 percent total protein, 30 percent total fat (less than 8 percent from saturated fat), and 46 percent total carbohydrate.

High-carbs favoured
The researchers found no changes in mood among the 93 participants consuming either the low- or high-carbohydrate diet for the study duration. They did find, however, a small between-group difference, favouring the high-carb dieters, in the speed at which participants performed intelligence and reasoning tests.

The findings suggest, Brinkworth noted, that "very low carbohydrate diets may offer less benefit than a high carbohydrate diet for improving cognitive function."

The investigators say further research is needed to determine whether similar outcomes occur with similar diets of longer duration.

SOURCE: The American Journal of Clinical Nutrition, September 2007. – (Reuters Health)