If you've ever weighed yourself when you wake up in the morning and before you go to bed, you've probably noticed the numbers on the scale weren't the same.

Our body weight can actually fluctuate about 5.5 pounds (2.5 kg) a day. Here's where those pounds can come from - and where they can go.

Most of these changes occur because of bodily functions like eating, drinking, and going to the bathroom.

On average, about 52 to 55 percent of women's body weight comes from water, while it's about 60 percent for the average man.

That's why men are supposed to drink 13 cups and women are supposed to drink 9 cups of beverages a day. You have to replenish the most plentiful part of your weight, after all.

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If you get food poisoning and have severe vomiting and diarrhea, for example, you could lose up to a gallon of water a day.

That could drop your weight a bit lower until you get rehydrated, since 1 gallon of water (3.8 litres) weighs about 8 pounds (3.8 kg).

But everyday weight fluctuation is totally normal, so don't worry if the scale says a slightly higher number than you think it should.

This article was originally published by Tech Insider.