Weight Loss in view of physical fitness, health and medicine weight loss has been defined as a reduction of body weight due to various factors like mean fluid loss or body fat .It can also be due to loss of bone mineral deposits, muscle and other connective tissue. A conscious effort to improve an overweight or obese state can lead to loss of weight.

Various diseases have been attributed to this phenomenon of weight loss. For example HIV is known to alter metabolism that in turn leads to weight loss. Overactive thyroid, a case of hormonal disruptions leads to the same. A recent outbreak in the world of science has shown fidgeting to cause acute weight loss. Loss of body mass in an attempt to improve fitness and appearance has been termed as Intentional weight loss. When the body consumes more energy than it has gained, it tries to breakdown stored reserves form fat or muscle, eventually causing weight loss.