If stepping on the scale after a weekend of serious eating and drinking has you freaking out, we’ve got good news: It’s totally normal to fluctuate up to 5 pounds in a day. Most of the time, salt and water are the culprits, Katherine Zeratsky, a nutritionist at the Mayo Clinic, tells Quartz. You need both, but if you go crazy on the salt (easy to do if you’re eating out), your body holds onto the water to get that balance back. And there’s your extra five pounds!

Besides salt and water, how many carbs you eat and (for all the ladies out there) where you are in your menstrual cycle can also explain why the number on the scale seems off. We’ve got a full guide with everything you need to know about weight fluctuations—just click the button below.

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