Weight loss may refer to the loss of total body mass in an effort to improve fitness, health, and/or appearance.
Therapeutic weight loss, in individuals who are overweight, can decrease the likelihood of developing diseases such as diabetes. Overweight and obese individuals face a greater risk of health conditions such as type 2 diabetes, heart disease, high blood pressure, stroke, osteoarthritis and certain types of cancer. For healthy weight loss, a physician should be consulted to develop a weight loss plan that is tailored to the individual.
Weight loss occurs when an individual is in a state of negative energy balance. When the human body is spending more energy in work and heat than it is gaining from food or other nutritional supplements, it will catabolise stored reserves of fat or muscle.
Although weight loss may involve loss of fat, muscle or fluid, weight loss for the purposes of maintaining health should aim to lose fat while conserving muscle and fluid.[citation needed]
It is not uncommon for people who are already at a medically healthy weight to intentionally lose weight. In some cases it is with the goal of improving athletic performance or to meet weight classifications in a sport. In other cases, the goal is to attain a more attractively shaped body. Being underweight is associated with health risks. Health problems can include difficulty fighting off infection, osteoporosis, decreased muscle strength, trouble regulating body temperature and even increased risk of death.