Carbs Before Bed, What Does Science Say?
We’ve all heard it, either from a family member or a friend at work, carbs are evil and we shouldn’t be eating them before bed. Eat carbs after sunset and it all goes to fat. So, where did this no carbs at night thing come from? And is there any proof to back up these claims?
Most ‘experts’ who recommend limiting carbs at night do so because their assertion is since you will be going to sleep soon, your metabolism will slow down and those carbohydrates will have a greater chance at being stored as fat compared to if they were consumed earlier in the day where they would have a greater probability of being burned. The logic behind this seems reasonable enough, you are laying down, not moving, so obviously, you aren’t burning as many calories as you would throughout the day. Well, in a study done by Katoyose et al. and colleagues (1) they found that during sleep the metabolic rate was not lower than when tested during the day. Additionally, it was noted that exercise seemed to increase one’s metabolic rate during sleep.
Before we put this myth to rest, ‘experts’ also often claim that insulin sensitivity is reduced at night, shifting your carb storage towards fat and away from muscle. Again, this does sound reasonable, insulin does go up and down and affects how carbs are stored. To see if this theory had any merit a study was conducted in Israel by Sofer S and colleagues (2) where people were placed on a calorie restricted diet for 6 months and split them into 2 groups. Each group consumed the exact same food and amounts but distributed their meals very differently. One group ate their food during the day, and the other consumed 80% of their food at night. What they found was quite the opposite to what was previously believed, the group consuming their food at night lost significantly more weight and bodyfat than the other group, they were also better satiated and less hungry!
Now there are a lot of factors that come into play here with insulin sensitivity and hunger, I am not advising eating most of your food before bed because spacing your meals throughout the day does have other benefits such as increased lean body mass, but that’s a topic for another day. With all the studies out there now disproving these wild theories, we can safely say that in this day and age, the myth of carbs before bed being bad is now busted!
1) Katayose Y, Tasaki M, Ogata H, Nakata Y, Tokuyama K, Satoh M. Metabolic rate and fuel utilization during sleep assessed by whole-body indirect calorimetry. Metabolism. 2009 Jul;58(7):920-6.
2) Sofer S, Eliraz A, Kaplan S, Voet H, Fink G, Kima T, Madar Z. Greater weight loss and hormonal changes after 6 months diet with carbohydrates eaten mostly at dinner. Obesity (Silver Spring). 2011 Oct;19(10):2006-14.