Effect of food deprivation on treadmill running in dogs

¹ Quartermaster Food and Container Institute for the Armed Forces, Chicago, Illinois

Effect of food deprivation on endurance capacity was studied in dogs under the following conditions: a) 3 and 5 days of fasting with daily high levels of energy expenditure and b) 15 days of fasting with low daily levels of energy expenditure. Relative maximum performance, i.e. endurance capacity under conditions wherein work dehydration is a limiting factor, is unaffected by 10–15% body-weight loss and hypoglycemia induced by acute food deprivation. Even with weight loss up to 22%, capacity for daily moderate levels of work is well maintained. Absolute maximum performance (water provided exhaustive treadmill running) improves with 5 days of fasting. Associated with 74% increase in endurance capacity, there is an increased mobilization of body tissue for fuel for the working muscles and a large increase in the post-exercise blood glucose concentration. The dog is resistant to starvation ketosis. In animals tested for absolute performance capacity, the average cumulative calorie deficit, including the exhaustive running trial, was 7500 Calories; yet there was no significant change in the level of blood acetone. It is concluded that absolute performance in the dog increases with 5 days of food deprivation; this response is mediated by a unique permissive effect of such treatment particularly on ability to mobilize body energy reserves.