HELP!!! Did I Gain Weight Overnight?!?

We’ve all felt like this after a big meal!

We’ve all felt like this after a big meal!

HELP!!! Did I gain weight overnight?

Ugh! You’ve been doing so good all week! You were on top of your game, exercising, eating greens, and all that good stuff. But you really went overboard last night and treated yourself on a date night with the hubby. It was an all-out food-fest – drinks, appetizers, full meal (the lobster mac and cheese was sooooo good), and dessert (and you didn’t share).

Now you feel crappy and bloated, and to make matters worse your scale is telling you that you gained 5 lbs. since your last weigh-in a mere 24 hours ago. Double ugh!

Sound familiar?

In last week’s blog post I debunked the myth of fast weight loss, proving that it’s impossible to lose large amounts of fat in a short amount of time. The good news is that it goes both ways. While it is easier to gain weight than to lose it, I can confidently assure you that you did not gain 5 lbs. of fat overnight…and I’m going to do the math to prove it!

How much food would you actually have to eat to gain weight overnight?

How much food would you actually have to eat to gain weight overnight?

Is it possible to gain 5 lbs. overnight or from a single meal?

Let’s do the math!

First I want to refresh your memory on a few of the numbers that we’ll use in our weight gain equation:

  • The average woman needs roughly 2,000 calories per day to fuel her body and normal activities (this does not include exercise).

  • There are roughly 3,500 calories in 1 lb. of fat.

To gain 5 lbs. of fat in a single meal (or overnight), our average female would need to eat 17,500 calories in excess of the 2,000 calories her body needs for that day. That means she needs to eat a grand total of 19,500 calories in 24 hours.

Let’s make this really easy and take her basic daily calorie needs out of the equation by pretending that she already ate 2,000 calories between breakfast and lunch. She has met her calorie needs for the day, so anything she eats during her date night dinner will now be stored as fat because it puts her in caloric surplus.

That means she needs to eat 17,500 calories at date night to gain 5 lbs. of fat.

Got all that?

You’d have to eat 17 slices of the Cheesecake Factory’s 1,000-calorie-per-slice NY style cheesecake to gain 5 lbs. of fat overnight!

You’d have to eat 17 slices of the Cheesecake Factory’s 1,000-calorie-per-slice NY style cheesecake to gain 5 lbs. of fat overnight!

So how much would you actually need to eat to gain weight overnight?

I am going to illustrate this using many common “date night” foods so you can see just how much our overzealous foodie babe needs to eat to have gained 5 lbs. of fat overnight. (Quick side note: I used several food tracking apps such as VeryWellFit and MyFitnessPal to come up with approximate calories and amounts for each of the foods listed below.)

Our date night babe would have to eat:

117 four-ounce filet mignon steaks

or…

75 four-ounce salmon filets

or…

128 four-ounce chicken breasts

or…

318 wings

or…

64 slices of pizza

or…

31 McDonald’s Big Macs

or…

44 medium-sized loaded baked potatoes

or…

90 eight-ounce glasses of red wine

or…

88 twelve-ounce IPAs

or…

56 one-cup servings of mac and cheese

or…

61 one-cup servings of pasta with red sauce

or…

44 half-cup servings of crème brulee

or…

17 slices of Cheesecake Factory New York style cheesecake

or…

53 half-cup servings of Haagen Dazs vanilla ice cream

or…

92 Krispy Kreme glazed donuts

Have I beat this dead horse enough? Did you really eat that much at your date night meal? If you did, I’m beyond impressed. That’s talent. You should be entering professional food-eating competitions!

Jokes aside, can you see how it’s nearly impossible to gain 5 lbs. of fat overnight or from a single meal? Let’s not forget that if the average woman were to eat 2,000 calories between breakfast and lunch, she would probably still feel quite full by dinner! It would be really hard to eat that much food!

Your scale is a liar. You did not gain weight overnight…at least not FAT weight!

Your scale is a liar. You did not gain weight overnight…at least not FAT weight!

Did I gain weight overnight? Why your scale is a liar.

The scale reflects your body’s relationship to Earth’s pull of gravity. That’s about it. It certainly does not differentiate whether a loss or gain came from fat, muscle, or water. You could cut off your arm and your scale won’t tell you that you are now an amputee. But it will tell you that you’ve lost about 15 pounds. Good for you.

The majority of scale fluctuations – especially those that occur in the span of hours or days – are simply due to changes in cellular water. In fact, water can account for as much as 10 pounds of weight gain (or loss) in a 24 hour period!

What influences cellular water?

Salt intake. It’s a well-known fact that salt can cause water retention. It’s also a well-known fact that restaurant food and processed food contain a lot of salt.

Carbohydrate intake. Ever noticed that the word carbohydrate has the word “hydrate” in it? Carbs are water-loving. When you eat carbs, your cells hold more water. Restaurant foods and treat meals are typically carb-rich. Between the carbs and salt, it should be no surprise that your weight is higher than it was prior to your date night meal.

Inflammation. Any type of inflammation will cause water retention. Processed foods cause low levels of inflammation. Being sick can cause inflammation. Even an intense workout can cause enough inflammation to make you gain a few pounds of water weight!

Hormones. We ladies know this all too well…the week before a menstrual cycle you feel like a blimp. While some of this is in our head, not all of it is imagined. Many women really do gain water weight before their periods.

Salt and carbs can leave you feeling bloated and fat, but that doesn’t mean you gained fat!

Salt and carbs can leave you feeling bloated and fat, but that doesn’t mean you gained fat!

Takeaway message: you did not gain fat overnight or from a single treat meal

Cut yourself a break. It’s almost mathematically impossible to gain 5 lbs. of fat overnight or from a single meal. Water weight? Maybe. But not fat. True, if you frequently overeat it will indeed cause weight gain over time. But that typically takes months or years, not hours or days.  

Bigger takeaway message: get rid of your scale! It gives you a completely useless bit of information that only serves to make you feel bad about yourself, which usually leads to further self-destructive behavior.


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I hope you enjoyed this post and thank you for reading!

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Blog Author: Kelly Bailey, IIN certified holistic nutrition coach, and NPTI certified personal trainer

Learn more about the author here.