When Your Weight Fluctuates: What’s Normal and What’s Not

Stop hating the scale and beating yourself up, and head off potentially permanent weight gain
By Jessica Smith

Although you know a number is just a number, it's hard not to worry when you see the scale jump a pound or two overnight or—worse—during the same day. But take a deep breath: Most weight fluctuations are normal.

Since most of us can’t eat enough in a day or two to actually gain 5 or 10 pounds, if you notice a dramatic increase on the scale, chances are it's due to water, says Anita Petruzzelli, M.D., doctor for BodyLogicMD.

“Eating, drinking, urinating, having a bowel movement, and exercise can all impact your body's water composition and therefore weight," she says. For example, high-carb and high-salt foods can cause water retention and a boost in poundage, while exercise can lead to temporary water and weight loss.

So don't get too excited—or freaked—if you weigh yourself after a meal or workout. “Weight gain due to water fluctuation should normalize in a day or two when you resume exercising and eating a healthy diet that's low in salt, refined carbs, and simple sugars," Dr. Petruzzelli says.

However, if those extra pounds keep showing up on the scale after you’ve returned to your regular routine for about a week, it may be time to make some adjustments to your lifestyle. Five is the magic number, according to Joseph Colella, M.D., a bariatric surgeon at Magee Women's Hospital at the University of Pittsburgh Medical Center. “Most people can recover five pounds rather quickly with minor tweaks to their calorie intake and physical activity.”

And if the scale shows a seven-pound jump for longer than a day or two, more aggressive measures may be called for, such as eliminating alcohol. "Alcohol stimulates your appetite and wrecks your self control regarding the amount of food that you consume," Dr. Colella explains.

The Best Way To Weigh
Despite the fluctuations, you can use a scale to your advantage to track and meet your weight goals.

If you want to drop just a few pounds, jump on every day. "That will give you a regular barometer and, over time, a trend line that you can use to reflect back on what you ate and what you weighed,” Dr. Colella says.

When you're aiming to lose more weight, though, daily check-ins can make or break your whole day. Avoid the unnecessary stress by checking in once a week, he recommends, and keeping tabs on what you are eating.

However often you face the scale, be consistent. Dr. Petruzelli suggests weighing yourself naked first thing in the morning after using the bathroom and always using the same scale.

And don’t forget to use other methods of progress measurement, especially if your weight-loss goal is more than a few pounds, since not all positive changes can be recorded by a scale. Regularly having your body composition checked can determine your body’s exact fat, muscle, and water content, and the way your clothing fits can also be helpful, Dr. Petruzelli says. If your clothes fit or are too loose but the scale says you've gained weight, the gain is probably muscle, she explains.

The Bottom Line
Weight fluctuation is normal, but if the scale rises five or more pounds for longer than a day or two, chances are it’s more than simply water weight and it’s time to make some adjustments.