Can You Gain Weight While You Sleep?

We have a big argument at work. Some people claim that just before you go to bed if you eat something with high calories, then weigh yourself and immediately go to sleep, then when you wake up in the morning you will weigh more than you did before sleeping. I think this is not possible since where would this extra weight come from? So my question is this, is it possible to weigh more on waking up in the morning than you did when you went to sleep? Thanks, Ray C.

Hi Ray,

What a fun question! I agree with you and have never known anyone to weigh more in the morning.

Where the weight would come from is just the weight of the food, not the calories from the food. There's also a chance extra water could be retained if the meal was very high in sodium, but that would be gone as soon as the person emptied their bladder in the morning.

One origin of this idea is the fact that your metabolism reduces slightly while you sleep because you are not moving around. So there are some advisors (in particular personal trainers) who recommend not eating before you go to bed on the theory those calories are less likely to be used up (especially if you have a big meal immediately before bed) and are more likely to be stored as fat. Most dietitians advise not to eat too much, too late, but having a light snack in the evening fits into a healthy eating plan for many people.

Technically, if you weigh yourself, eat a big meal, and then weigh yourself immediately again you will weigh more simply because the food is sitting in your stomach. The scale reads the weight the same whether you are holding a cheeseburger in your hand or you gulp it down into your stomach. However, food is broken down in the body within a few hours and as soon as you urinate or otherwise dispense of any waste, the scale will register a weight loss in the same way.
Just because the scale says you weigh more after drinking a quart of water, for example, doesn't mean you've "gained weight" as in "deposited fat weight".

Bottom line, the night time meal will have been completely absorbed by morning. You must have a 3500 calorie meal in order to register one pound of (fat) weight gain and this is pretty unlikely. In the unlikely event a person weighs more in the morning it will come off after emptying their bladder.