Weight Gain

Weight gain is an increase in body mass that can result from a rise in fat, muscle, fluid or a combination of these, and it is one of the most common findings noted in both routine and diagnostic medical care. Most weight gain reflects an energy intake that exceeds the energy the body uses, but sudden or unexplained weight gain can also signal an underlying medical condition, including an underactive thyroid gland, fluid retention from heart, kidney or liver disease, or certain medications such as corticosteroids and some antidepressants. Rapid gain of several pounds in a short time is more often due to fluid retention than to fat, since fat accumulation of that scale takes weeks rather than days. Because the pattern, speed and distribution of weight gain point toward different causes, clinicians evaluate it alongside a person's history and other symptoms rather than as an isolated number on a scale.