Weight Loss Unintentional (or unexplained) weight loss is a noticeable loss of body weight without much effort, such as calorie restriction, exercise, or lifestyle changes. Unintentional weight loss of 5 kg or 5% of normal body weight in 6 to 12 months or less can indicate the development of a serious disorder or disease: gastroenterological, endocrine, neurological, infectious, oncological. Unexplained weight loss is most common in the elderly. As a rule, it is in them that a sudden and...