Are you shocked to weigh yourself the next day and see the scale go up by 3lbs overnight. You might be thinking how can that be?

It’s can be stressful and scary to think that you gained weight so easily, but is it true weight gain?  I’m breaking it down in this blog today.

Let’s talk about the basics of weight.

1 lb of weight is 3,500 calories, yes 3 thousand five hundred calories. 1 slice of bread is about 120 calories, so that’s about 30 slices of bread. Or 1 slice of Hawaiian pizza is about 220 calories, so that’s about 16 slices of pizza- just for a visual comparison- obviously most of us will eat 30 slices of bread or 16 slices of pizza in a day.

To gain or lose weight, you would need to be in EXCESS of the calories it takes to maintain your weight. So we have an amount of calories we need to maintain our weight each day and calories above that will cause you to gain weight over time.

If 3,500 calories is 1lb, 3lbs would be 10,500 calories IN EXCESS of the calories needed to maintain your current weight. So that means you ate an equivalent of 47 slices of Hawaiian pizza in EXCESS overnight?

No, that’s unrealistic and very, very hard to consume in 1 day.  So then how can the scale show that you’ve gained 3lbs overnight?

Firstly, its completely normal for your weight to fluctuate throughout the day because of hydration and water retention and sodium.

When we eat foods throughout the day, it contains calories and are mostly made up of water. In fact, food can be up to 90-99% water content, like those found in spinach, watermelon, strawberries, or skim milk. Remember, water has 0 calories but carries weight, like if you put water on a scale, it will show weight.

1 cup of water is 236 grams and 454 grams is equivalent to 1lb. So, if you drink 2 cups of water, which is equivalent to 474 grams, which is slightly over 1lb. But this is actual weight gain? No, because you will just pee out the excess water that your body won’t use.

So, this is one reason why you will see the scale go up overnight and from morning to evening- because you are eating foods that contain water!


Secondly, if you are eating foods that contain a lot of sodium, like take out or frozen prepared meal item (these are known to be super high in sodium), then you’ll see “weight gain”, as well. This is because sodium in our body causes water retention through a process called osmosis. Do you remember high school chemistry?

Essentially, salt pulls water out of the cells from the osmosis process. When we eat salty foods, the high sodium will pull water from the cells to try to dilute it. It’s been said that your body can retain up to 1.5 liters of water when you eat too much salt.
The 1.5 liters of water is equal to about 6 cups of water (1 liter equals 4 cups) and as I mentioned above, 2 cups of water weighs about 1lb, so 6 cups of fluid is about 3lbs.

So, in short, it’s not that you ate too much that caused you to gain 3lbs overnight. It’s the type of food you ate and water content in the food that shows the weight gain, though not true weight gain.

So what can you do?  Take a deep breath (you’re ok!), relax, and try to minimize high sodium foods (take out, processed foods), get back to your normal eating routine for weight loss or maintenance, and weigh yourself again in a few days!

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