Let's say you've decided to lose weight and things are going well — you're changing your lifestyle, making healthy choices and the scale is starting to move.
But you're noticing a rather odd phenomenon, too: Is it your imagination, or are you visiting the bathroom a lot more than before you started your weight-loss journey? Could it be that losing weight makes you pee more?
Oddly enough, there is a link between your bathroom habits and the number on the scale. Here, two experts in weight loss give us the breakdown.
The Connection Between Weight Loss and Frequent Urination
Here's the gist: When fat is broken down, it releases fluid that has to be eliminated from the body in some way, and that outlet is usually your sweat and urine, Mir Ali, MD, bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in Fountain Valley, California, tells LIVESTRONG.com.
Mary Margaret Dagen, MD, and obesity specialist with Spectrum Health Bariatrics in Grand Rapids, Michigan, gives us a more detailed explanation.
"Fat cells store fat. When we have less fat going in overall because of a calorie deficit, the fat cells release their stored fat into the body to use for general functions," she says. "If you are taking in less calories daily, then there is no extra fat to fill the fat cells back up. They therefore shrink down in size."
Ultimately, Dr. Dagen says, those shrunken-down fat cells are broken down themselves by the body to become an energy source. And when that happens, the energy is released in the form of carbon dioxide — which we breathe out — and water, which we sweat or pee out. Mystery solved!
But wait, there's more: Dr. Ali adds that if you're losing weight through a ketogenic diet, you will most likely notice an even larger increase in urination because of the high level of fat loss triggered by low-carb diets.
"It doesn't matter how you lose weight, but most diets reduce carbs to force the body to burn more fat," he says. "Keto diets tend to notice it more."
3 Other Reasons You Might Pee More When You're Losing Weight
Along with the physical breakdown of fat cells into carbon dioxide and water that can lead to peeing more, Dr. Dagen says there are several other reasons that losing weight may lead to a noticeable increase in urination.
1. You've Changed Your Diet
"Losing weight generally requires changing food choices, such as eating more fruits and vegetables," she notes. "These foods are made up of more water, so you may pee more because of the types of foods you take in."
According to the Asia Pacific Journal of Clinical Nutrition, vegetables and fruit with high water content include strawberries, raspberries, peppers, tomatoes, mushrooms, celery, carrots, cabbage, cucumber, Brussels sprouts and mango.
2. You're Drinking More Water
Along with eating healthier foods, making a healthy lifestyle change often means drinking more water.
Many weight-loss plans tout increasing your water intake as a strategy to keep full and cut calories by replacing any sweetened beverages you may have been drinking before. But all of that increased hydration will definitely lead to more frequent bathroom breaks, too.
3. You've Upped Your Caffeine Intake
"If your modifications include a change in caffeine intake, this can alter how much or how often you pee," Dr. Dagen says.
Some research, such as a 2019 meta-analysis in Critical Reviews in Food Science and Nutrition, links caffeine intake with fat loss and BMI reduction. If you're incorporating weight-loss products that contain caffeine into your weight-reduction strategy, that could mean more trips to the restroom.
Differences Between Men and Women
Both men and women tend to pee more when losing weight, but with a few differences, Dr. Dagen says.
Because of their overall higher levels of lean muscle mass, men can lose weight at a faster rate initially than most women, which can lead to more rapid fat loss and initial increased urination.
On the flip side, women generally have more fat mass than men, so they may experience increased urination for longer periods of time with weight-loss efforts.
When to See a Doctor About Increased Urination
Any increased urination you're seeing as a result of weight loss won't stop as long as you continue to lose weight. "As long as you are breaking down fat, you will be releasing fluids in the fat," Dr. Ali says.
But if you're not specifically trying to lose weight and have noticed an increase in your urination patterns, you should schedule a checkup with your doctor. "If you're not dieting or trying to lose weight, one of the signs of diabetes is urinating more," he notes.
And outside of any deliberate weight loss, Dr. Dagen cautions that certain urination changes may warrant a checkup with your doctor. For instance, if you are experiencing any pain or burning with urination, increased sensation of frequency in urination with little production or blood in your urine, these all warrant further evaluation by a medical provider.