(May 30, 2002) Bethesda, Md. Scientists have long believed that in all animals (including humans), innate physiological ability exists to seek out sources of nutrients (minerals) deficient in the major food source available to them. Their beliefs originate from a series of studies in which test animals were allowed to choose from one container of each nutrient leading to the identification of "nutritional wisdom. These tests proved that there is a natural disposition to select a balanced diet with all necessary nutrients and suitable for the respective environment.
Unfortunately, the nations soaring obesity rate offers evidence that in the animal kingdom, humans are flunking in their nutritional wisdom. Where nature fails to reduce weight, human ingenuity (and marketing) takes over with a billion dollar industry advancing programs that entreat Americans to modify their habits and regain their nutritional wisdom and return to their normal and slimmer weight.
This may not be so easy and overweight Americans may be throwing their money away. New study findings suggest that nutritional wisdom goes out the window when unhealthy food choices are more available than healthier nutrients. Tests with rodents found that the number of containers of each nutrient provided markedly influenced consumption rates. Most rats given a choice from separate sources of protein, carbohydrate, and fat thrived if given one cup of each but half failed to thrive if given one cup of each and three extra cups of carbohydrate or fat. Rats given five bottles of sucrose solution and one bottle of water became fatter than rats given five bottles of water and one of sucrose.
These studies in rats may point to a model for human obesity, in which the availability of the wrong food can override physiological controls of ingestion. The author of "Obesity by choice: the powerful influence of nutrient availability on nutrient intake," is Michael G. Tordoff, Mon
Contact: Donna Krupa
American Physiological Society