If it’s upsetting to you to find weight fluctuations of any type every day then avoid weighing yourself more than weekly. Adding stress just triggers a weight increase due to cortisol being released.

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You’ve probably asked yourself, at least once, “Why does my weight fluctuate so much?” Weight fluctuation throughout the course of a day is normal. Weight fluctuation throughout the course of your life can be harmful. Sounds contradictory, doesn’t it? It’s not.

A person should strive to maintain a lifelong, consistent healthy weight.  Fluctuation in large amounts throughout your life—that lose-gain-lose-gain cycle so many of us battle, the so-called “yo-yo dieting”—may tax the cardiovascular system, set the stage for diabetes, slow metabolism, and make it increasingly more difficult to lose weight.

As if that’s not enough, it can permanently stretch skin out of shape (yes, permanently), which worsens as you age, says Health.com. Exercise cannot bring it back once it reaches that stage. “The expansion and contraction of the skin is what plays havoc,” Alan Matarasso, MD, clinical professor of surgery at the Hofstra/Northwell School of Medicine (N.Y.) told Health.com.

The key to maintaining a stable and healthy weight is not short-term diets but long-term healthy lifestyle habits that include healthy eating, exercise, and balancing calories in with calories used.

How Much Does Weight Fluctuate During the Day?

People normally experience weight fluctuation throughout the course of a day. That change can be as large as four or five pounds, mainly due to fluids and salts. (Read some weight-loss forums, however, says Livestrong.com, and you may hear about weight fluctuation up to 10 pounds; if you’re experiencing that you should seek help from a doctor. 10 pounds in a day is not normal weight fluctuation.) Most of us weigh the least amount in the morning, after we void, and the most at the end of the day, especially if we eat a big, late dinner.

Causes of Weight Fluctuation

Weight can temporarily increase due to:

• Constipation
• Exercise
• Food
• Hormones
• Medications
• Salt
• Water
• Weather

“Since most of us can’t eat enough in a day or two to actually gain five 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, in an article in Shape. “Eating, drinking, urinating, having a bowel movement, and exercise can all impact your body’s water composition and therefore weight,” she says. True weight gain or loss takes time, while small weight fluctuation in a day just comes from these few factors.

“In the summer, body weight can go up by several pounds due to increased body water. This is accomplished through fluid-conserving hormones such as aldosterone, which allows the kidney to retain more fluid and reduces the amount of salt in sweat, a measure that also aids in water retention. The increase and stabilization of total body water can only be accomplished by continuing to exercise in hot weather and will not occur in people who spend most of their time indoors in air-conditioned environments,” explains John Castellani, a researcher in the Thermal & Mountain Medicine Division of the U.S. Army’s Research Institute of Environmental Medicine on ScientificAmerican.com.

Weight can temporarily decrease due to:

• Crash diets
• Dehydration
• Exercise
• Illness
• Low-carbohydrate intake
• Voiding (urine and feces)

How to Properly Weigh Yourself

Most studies reveal that a daily weigh-in is the way to go to maintain your weight, as it seems to produce the best results, cautioning that the person should choose the same time of day every day to do the weigh-in and, this is important, weigh yourself when you’re naked. Clothing and shoes can vary in weight, so it’s best to eliminate them.

That said, if it’s upsetting to you to find weight fluctuations of any type every day then avoid weighing yourself more than weekly. Adding stress just triggers a weight increase due to cortisol being released. The only trick will be staying motivated to stick to your diet and fitness routines.

This article was originally published in 2018. It is regularly updated.