Why Does Your Weight Fluctuate?

Holly Lofton, MD, director of the Medical Weight Management Program at NYU Langone Health, and Eduardo Grunvald, MD, FACP, medical director of the UC San Diego Weight Management Program, talks about fluctuations in weight mainly due to fluids as well as fat loss and gain. It's harder to put on muscle than it is to put on fat. Dr. Grunvald noted initially that if we're talking about longer-term change in weight, “we're talking about fat weight, although muscle weight can also fluctuate.” There are instances, too, when medical disorders will affect your weight, which we discuss ahead.

Dr. Lofton said that weight tends to go up during the day — as much as five pounds — because we eat and drink and don't eliminate all of it. This, she said, is the obvious reason. It also has to do with sodium in certain food, which draws in water. Things that are rich in sodium (potato chips, for example) keep water in the bloodstream, which makes our weight on the scale increase. “We urinate less with the salty food and thus hold onto more water,” she explained. Other things that may affect weight include physical activity. “Every time we move, our muscles contract. They use carbohydrates and water to contract and that can lead to some temporary swelling, which can manifest as weight gain on the scale,” Dr. Lofton said. Continue reading…