The flip side of obesity: those who undereat.
D000293:Adolescent; D000328:Adult; D002648:Child; D004032:Diet; D004435:Eating; D002149:Energy Intake; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D000090463:Iron Deficiencies; D008297:Male; D009751:Nutritional Requirements; D009765:Obesity / Q000378:metabolism; D011247:Pregnancy