The purpose of this study is to demonstrate the beneficial effect of undernutrition and reduction in weight on the heart and circulation. The influence of a low calory diet on pulse rate, blood pressure, oxygen consumption, arteriovenous oxygen difference and cardiac output was determined over a long period in normal overweight subjects.
In obesity the heart functions under two handicaps. In the first place, the increased surface area results in an absolute rise in total body metabolism and oxygen consumption, which augments the work of the heart. Secondly, the elevated diaphragm limits the respiratory movements and compresses the lungs, causing a reduction in vital capacity. Both of these factors place a burden on the heart and explain the tendency of obese persons to fatigue and to dyspnea on mild effort, indicative of diminished exercise tolerance.
In studies on dietary restriction in subjects of normal weight Benedict and his co-workers1