#Weightgain occurs when more energy (as calories from food and beverage consumption) is gained than the energy expended by life activities, including normal physiological processes and physical exercise.[1]
If enough weight is gained due to increased body fat deposits, one may become overweight or obese, generally defined as having more body fat (adipose tissue) than is considered good for health.[1] The Body Mass Index (BMI) measures body weight in proportion to height, and defines optimal, insufficient, and excessive weight based on the ratio.[2] weki
Causes In regard to adipose tissue increases, a person generally gains weight by increasing food consumption, becoming physically inactive, or both. When energy intake exceeds energy expenditure (when the body is in positive energy balance),
the body can store the excess energy as fat. However, the physiology of weight gain and loss is complex involving numerous hormones, body systems and environmental factors. Other factors beside energy balance that may contribute to gaining weight include: Social factors A study, involving more than 12,000 people tracked over 32 years, found that social networks play a surprisingly powerful role in determining an individual's chances of gaining weight, transmitting an increased risk of becoming obese from wives to husbands, from brothers to brothers and from friends to friends.[7] [8]
