Calories Make Old Brains

It’s an indisputable tenet of aging, proved over and over in laboratory animals, that eating less food extends life spans. In short, calorie restriction slows down the aging process throughout your body, including your brain. A brain fed overgenerous amounts of calories gets older and damaged faster. When lab animals are put on low-calorie diets, trim­ming 30 to 40 percent off their food intake, they live one-third to one-half longer than expected. Such animals are usually only half the biological age of normally fed animals of the same chronological age. Everything about them is younger, including their brains and memories.

One reason is simply a matter of processing calories. In order to metabolize calories, you must burn oxygen, gen­erating free radicals. Thus, the more calories consumed, the more free radicals created to damage cells including neurons. Consequently, the faster your mental faculties fade. Animals that burn fewer calories over a lifetime show much less free radical damage in their cells when they are examined after death. Besides curtailing free radical pro­duction, underfeeding also dramatically raises production of internal antioxidant defenses, supplying more brain-pro­tective superoxide dismutase and glutathione to zap the free radicals that would destroy your neurons.

One bit of human confirmation: The islanders on Japan­ese Okinawa who for years ate a diet with 17 to 40 percent fewer calories than other Japanese had 30 to 40 percent less chronic disease, including neurodegenerative disorders such as Alzheimer’s.