Weight loss

Weight loss is defined as a reduction in body weight caused by either deliberate (diet, exercise) or involuntary (illness) factors. The majority of weight loss is caused by the reduction of body fat, but in circumstances of excessive or severe weight loss, the body's protein and other nutrients can be reduced as well. Cancer-related weight loss, malabsorption (such as from persistent diarrheal diseases), and chronic inflammation are all examples of involuntary weight loss (such as with rheumatoid arthritis).