Dr John McDougall
Brain Impairment from the Atkins Diet
Low-carbohydrate weight-loss diets. Effects on cognition and mood by Kristen D’Anci in the February 2009 issue of the journal Appetite concluded that,“The present data show memory impairments during low-carbohydrate diets at a point when available glycogen stores would be at their lowest.” Women followed a low-carbohydrate diet, similar to the Atkins diet, or a reduced-calorie balanced diet, similar to that recommended by the American Dietetic Association (ADA). “Results showed that during complete withdrawal of dietary carbohydrate, low-carbohydrate dieters performed worse on memory-based tasks than ADA dieters. These impairments were ameliorated after reintroduction of carbohydrates.” After about one week of severe carbohydrate deprivation subjects demonstrated impairment of memory.
Comments: Have you noticed any of your dieting friends slipping with their physical or mental health? There are scientific reasons to believe this is a real change caused by a deficiency of “brain fuel,” which is carbohydrate. Sugar (glucose) is the primary, preferred fuel for the brain and it is not stored in the brain tissues. Thus, the brain is dependent upon circulating glucose in the blood stream. This glucose comes almost exclusively from eating carbohydrates. Except for milk and honey, only plant-derived foods contain carbohydrate. The body’s stores of carbohydrate last about 24 to 72 hours after starting on a low-carbohydrate, Atkins-type diet. Upon depletion of carbohydrates the body metabolizes body fat into ketones, which can be used, but less efficiently, by the brain tissues and other body tissues for fuel.
The popularity of low-carbohydrate diets is waning, but I doubt they will vanish because they promise quick weight loss while consuming familiar foods like beef, butter and Brie. These diets work by simulating sickness. Without carbohydrate the body turns to fat for energy. Ketones are produced from fat metabolism and with their accumulation a condition of ketosis develops. Ketosis suppresses the appetite. Weight loss follows as long as ketosis-induced, appetite-suppression, is maintained. Most dieters cannot tolerate the unpleasantness of sickness for long and they give up, regaining all their lost body fat.
The foods consumed for a low-carbohydrate diet (meat, poultry, fish, cheese, eggs) are known to cause many serious illnesses, including heart disease, strokes, cancer, osteoporosis, and constipation. This is not the right way to lose weight.
D’Anci KE, Watts KL, Kanarek RB, Taylor HA. Low-carbohydrate weight-loss diets. Effects on cognition and mood. Appetite. 2009 Feb;52(1):96-103.