A reduction in total body mass caused by a mean loss of fluid, body fat (adipose tissue), or lean mass (i.e., bone mineral deposits, muscle, tendon, and other connective tissue) is referred to as weight loss in the context of medicine, health, or physical fitness. Weight reduction can happen unintentionally as a result of malnutrition or an underlying disease, or it can result from an active effort to reduce actual or perceived overweight or obesity. Cathexis is the term for "unexplained" weight loss that is not brought on by calorie restriction or exercise, and may be a sign of a significant medical condition.

   Intentional

A person who intentionally loses weight does so in an effort to alter their appearance by slimming down or to improve their fitness and health. The primary treatment for obesity is weight loss [1], [2], [3], and there is strong evidence that this helps maintain cardio metabolic health in diabetics with a 5–15% weight loss and prevent progression from prediabetes to type 2 diabetes with a 7–10% weight loss. [4]

For people who are overweight or obese, losing weight can lower health risks, improve fitness, and possibly postpone the onset of diabetes. [5] It might alleviate discomfort and improve mobility in people with knee osteoarthritis. [6] Losing weight can lower hypertension (high blood pressure); however, it's unknown whether this will lessen hypertension. -related damage.

             Myths

Some widely held notions about weight loss have been demonstrated to either have less effect than generally thought or to be actively unhealthy. The notion that metabolic rate is the "key to weight" is described as "part truth and part myth" by Harvard Health because, while external factors like nutrition and exercise have an equal impact on weight loss, metabolism does have an impact on it. [62] They added that there is disagreement about the idea of altering one's rate of metabolism. [62] Fitness magazine diet programs are frequently perceived as helpful but may actually be harmful since they restrict the daily intake of essential calories and nutrients, which, depending on the individual, may be damaging and even deter people from trying to lose weight.

            Health effects

Diabetes, cancer, cardiovascular disease, high blood pressure, and non-alcoholic fatty liver disease are just a few of the health problems that obesity makes more likely. Lowering obesity reduces those dangers. Blood pressure has been shown to decrease by about 1 mm Hg for every kilogram of body weight lost. [64] In overweight and obese people, intentional weight loss is linked to gains in cognitive function.

             Diet and exercise

Adjustments to dietary habits and increased physical activity, usually in the form of exercise, are the least invasive weight loss strategies and those that are most frequently advised. [20] The World Health Organization advises people to improve their physical activity while consuming fewer processed meals that are heavy in sugar, salt, and saturated fats. [21]. [22] Long-term exercise regimens and anti-obesity drugs both lessen the volume of abdominal fat. [23] Self-monitoring of nutrition, activity, and weight are helpful weight reduction techniques [20], [24], [25], especially when weight loss programs are just getting started. [26] According to research, people who track their meals roughly three times per day and 20 times per month are more likely to lose weight that is clinically meaningful.