The effect of addition of exercise to a regime of dietary restriction on weight loss, nitrogen balance, resting metabolic rate and spontaneous physical activity in three obese women in a metabolic ward.

Three obese women were studied for periods of 12-13 weeks while on a constant reducing diet (800 kcal/day) in a metabolic ward. Body weight and nitrogen balance were measured throughout the study and patients kept continuous diary card records of their physical activity. Fasting resting metabolic (BMR) was measured twice weekly using a ventilated hood apparatus. Each patient acted as her own control by alternatively exercising (2 h/d on a bicycle ergometer) or not exercising for consecutive 3-4 week periods. Rate of weight loss was not increased by this level of exercise over the 3-4 week periods. This surprising result could not be explained by a decreased nitrogen loss since nitrogen balance was not significantly affected by the exercise, not could it be explained by a compensatory decrease in subsequent energy expenditure since BMR and spontaneous activity was not measurably affected by the exercise. However, since exercise increases muscle glycogen stores it may have been this effect which negated the expected increase in weight loss during ther exercise programme.