When you’re trying to lose weight, it can be hard to not want to weigh yourself 50 times a day. But the truth is, the more you weigh yourself, the more you wind up getting different weight amounts.

That’s because your weight fluctuates at many points in the day for many different reasons. For example, every ounce of food you put in your body can contribute to a different number on the scale. So depending on when you step on the scale, you might notice totally different numbers.

Obviously, eating and drinking doesn’t mean you’ve suddenly gained fat. But it’s the fact that high salt foods—things like cold cuts, frozen meals, canned soups, etc.—can cause water retention, contributing to a higher number on the scale.

Additionally, carbohydrates are another culprit for making your weight go up. For every gram of carbohydrate you consume, your body retains about three grams of water. That means your body weight is likely to increase, even though you didn’t gain more fat.

Heck, even a few sips of water can contribute to weight fluctuations. Drinking just two cups of water (including the water from food) can increase your weight by a whole pound!

Of course, after you eat or drink, your body has to get rid of the waste somehow, which is why you go to the bathroom. It’s no coincidence that the number on the scale might go down after that.

Because of all of these reasons, it only makes sense that you shouldn’t be weighing yourself at various times of the day.

What’s the best time to weigh myself?

There’s really only one good window of time for you to hop on the scale, and that’s first thing in the morning, right after you go to the bathroom, and preferably with no clothes on. The moment you drink your morning cup of coffee, that weight can differ. And even just your underwear on can skew the numbers, too.

Experts also say that while it’s good to weigh yourself every day, it’s important to realize that the numbers will vary from day to day. Weight is not something you should take literally—it’s something that you should consider an average over time.

“Individual body weight on a given day is irrelevant,” says Charlie Seltzer, MD, an obesity medicine physician and exercise specialist in Philadelphia. “You have to look at the trends over time, so that one day’s weight is simply a data point.”

So then how can you accurately tell if you’re losing weight? It’s not something you should expect from one day to the next, Dr. Seltzer explains.

“Fat loss is a slow process and dramatic weight loss doesn’t happen on a daily basis,” he says. “You want to see your weight moving down at a rate of about one pound per week, but know that every week may not be perfect, and that goal may be different depending on your starting weight.”

Have you noticed that your weight fluctuates if you’re weighing yourself at different times of the day? At what time of day do you typically weigh yourself?