Food intake of very obese persons: quantitative and qualitative aspects

To document the caloric intake of very obese persons and investigate the food choices and dietary composition that maintain severe obesity, we studied the self-selected food intake required to maintain stable weight in two groups of very obese subjects: 11 inpatients with a mean weight 181% above desirable body weight and 35 outpatients with a mean weight 125% above desirable body weight. Qualitative and quantitative food intake were evaluated using records obtained on the hospital metabolic ward for the inpatients and using self-recorded food records for the outpatients. Absolute caloric intake in both groups was greater in proportion to the degree of obesity (deviation from desirable body weight); caloric intake per unit of lean body mass (kilocalories per gram urinary creatinine) was constant regardless of the degree of obesity and was essentially the same as that of normal nonobese persons. Food records indicated that the obese subjects maintained their high caloric intake by consuming mostly foods of high caloric density, with occasional binge eating. They largely avoided foods of low intrinsic energy density and modified-calorie foods, ie, foods with decreased fat, nonnutritive sweeteners, or fillers. By substituting foods of lower caloric density for usual food choices from the same food group, obese persons could decrease caloric intake by 20% and increase potential for notable weight loss.