Medical myths: Eating before bedtime makes you fat

Max Pemberton

Know your medical facts from myths? There are a lot of old wives' tales out there. But where do they come from and what is the truth? This week, does eating before bed make you fat?


What's the truth?

 All you lovers of midnight snacks, fear not. There's no evidence that eating late at night increases weight gain. The simple truth is that if you eat more calories than you expend, you'll put on weight; if you eat fewer, you'll lose it. The time of day you consume those calories doesn't really matter.


Where did the myth come from?

Eating at night

It seems to be from a number of fad diets that discouraged the eating of carbohydrates past a certain time in the evening. The theory is that if you eat carb-rich food and then go to bed, the body isn't able to use the energy because you're asleep, and so stores it as fat. But this simply isn't how the body works — and there's not a jot of evidence to say otherwise.

Don't get too complacent, though: snacking at any time of day can lead to weight gain, so you do still have to watch your daily calorie intake.


So there's nothing to worry about?

Well, while eating late at night might not make you any fatter than eating at any other time of day, that doesn't mean it's not bad for your teeth—if you don't brush them after eating and before going to sleep.

When we sleep we produce less saliva and this means the bacteria in our mouths can reproduce more. If there are still sugars from our food in our mouth, more bacteria can grow, and do even more damage to our teeth.