Obesity is a condition in which the natural energy reserve, stored in the fatty tissue of humans and other mammals, exceeds healthy limits. It is commonly defined as a body mass index (weight divided by height squared). Although obesity is an individual clinical condition, some authorities view it as a serious and growing health problem. Some studies show that excessive body weight has been shown to predispose various diseases, particularly cardiovascular diseases, diabetes mellitus type 2, sleep apnea and osteoarthritis.
Most researchers have concluded that the combination of an excessive nutrient intake and a sedentary lifestyle are the main cause for the rapid acceleration of obesity in Western society in the last quarter of the 20th century. Obesity caused specifically by overeating is called exogenous obesity. Despite the widespread availability of nutritional information in schools, doctor’s offices, on the internet and on product packaging, it is evident that overeating remains a substantial problem.
Less well established and possibly under investigated life style issues that influence obesity include, insufficient sleep, endocrine disruptors, food substances that interfere with lipid metabolism, decreased variability in ambient temperature, decreased rates of smoking, which suppress the appetite, increased use of medication that leads to weight gain, increased distribution of ethnic and age groups that tend to be heavier, pregnancy at a later age, positive natural selection of people with a higher BMI, assortative mating, heavier people tending to form relationships with each other.
The main treatment for obesity is to reduce body fat by eating fewer calories and exercising more. A loss of as little as 5% of body mass can create large health benefits. Much more difficult than reducing body fat is keeping it off. 80 to 95% of those who lose 10% or more of their body mass by dieting regain all that weight back within 2 to 5 years. Keeping weight off generally requires making exercise and eating right a permanent part of a person’s lifestyle