Risks of obesity

Obesity is a chronic disease in the same sense as hypertension and atherosclerosis. The cause of obesity is an imbalance between the energy ingested in food and the energy expended. The excess energy is stored in fat cells that enlarge or increase in number. This hyperplasia and hypertrophy of fat cells is the pathologic lesion of obesity. Enlarged fat cells produce the clinical problems that are associated with obesity, either because of the weight or mass of the extra fat or because of the increased secretion of free fatty acids and numerous peptides from enlarged fat cells. The consequence of these two mechanisms is other diseases, such as diabetes mellitus, gallbladder disease, osteoarthritis, heart disease, and some forms of cancer.