Junk Food Diet, Obesity, Lead To Lethargic Behavior

Diet experiments conducted in rats found that, as expected, animals who ate highly-processed junk food for three months gained considerably more weight than those who ate standard, unprocessed foods. Researchers at UCLA also found that the obese rats appeared lazier than the  lean  rats, taking substantially longer to return to assigned tasks after breaks. After switching the diets for several days, there was no significant change in weight or performance in the two groups: the lean rats did not suddenly get fat, nor did the fat rats get lean. This finding suggests that the long-term pattern, not the occasional binge, is responsible for obesity and cognitive impairments.