7 Reasons You Gain Weight Overnight and What You Can Do About It

Updated on 9/1/2016 at 12:05 PM

POPSUGAR Photography | Sheila

You hit the gym superhard yesterday. You stuck to your diet like a saint. Then, you wake up and step on the scale, just knowing you are going to see that magic number you were hoping for . . . only to be disappointed when you've actually gained a few pounds.

As a nutritionist, I always tell my clients not to weigh themselves more than once a week because it is so easy to let a number get in your head and ruin your whole day. It's literally impossible (well, almost impossible) to gain three pounds of fat overnight. You would have to eat 10,500 extra calories in one day — that's almost 20 Big Macs!

Still think you really gained three pounds overnight? Here are seven reasons to explain why you did and why that weight won't stick around permanently.

You Drank Too Much Water

This one is just simple math. Thirty-two ounces of water is equal to two pounds. If you drink more than your body needs and you have yet to, umm, eliminate it, you may see a higher number on the scale the next morning.

You Went Heavy in the Gym

If you hit the weights hard yesterday, you may feel a little disappointed when you step on the scale the next day. Why? Weight-bearing exercise causes tiny tears in your muscle tissue, and, while these muscles are repairing and rebuilding, they may retain a little extra fluid to help the process along. This effect usually only lasts one to two days, but your newfound strength will be well worth it.

You Overindulged

This one is pretty much a no-brainer, but it’s worth mentioning. If you polished off the basket of chips and had a few too many margaritas at happy hour last night, you may experience temporary weight gain while your body is figuring out where it all goes. If it doesn’t have anywhere to go, those extra calories could be stored as body fat, but one night of indulgence will not cause permanent weight gain. Get back on track the next day and put those calories to work.

Your Sodium Intake Was Higher Than Normal

If yesterday’s menu was heavy on the sodium, you may feel heavier the next day, too. Sodium can cause water retention, and things like frozen meals, deli meat, and soy sauce are all high in sodium. Drink a few extra glasses of water to help flush the sodium out of your system, and that water weight won’t stick around for long.

You Had a High-Carb Day

Whether you meant to or not, if you had cereal for breakfast, a sandwich for lunch, and pasta for dinner, you may see a couple of extra pounds on the scale the next day. Like sodium, carbs can also cause water retention. If you really want to shed that water weight quickly, stick to a lower carb diet the day after (think lean meats and fresh veggies), and it'll be gone in no time.

You Didn't Pay a Visit to Restroom First Thing in the Morning

How do I put this delicately? A "number two" can actually weigh a couple of pounds, and, if you haven't yet cleared the pipes, you may see those couple of pounds reflected on the scale. Make sure you always weigh yourself under the same conditions — first thing in the morning, after using the restroom, and before eating or drinking.

Aunt Flo Is on Her Way to Town

As if you needed another reason to love PMS, fluctuating hormone levels can actually cause you to retain water in the week before you get your period. The best way to fight water weight is by drinking plenty of water and eating a healthy diet, and it should disappear after your period, anyway. Unfortunately, I can't say the same about the weight gain from giving into those late-night PMS chocolate cravings . . .