I speculated that bedtime honey improves sleep because it consists of an equal mix of glucose and fructose. Glucose is used by the brain during the first half of the night. By the second half, the fructose has been converted to glucose. However, honey has other ingredients, so it is not obvious that fructose and glucose are responsible. I focused on them partly because a need for glucose and fructose during sleep would explain (in evolutionary terms) why we eat dessert after meals, a puzzling separation.
Other carbohydrates also increase blood glucose. Do other carbs also improve sleep? Stuart King (who told me how much bedtime honey improved his sleep) pointed me to a 2010 discussion on a body-building forum. One person wrote:
I save a good portion of my carb intake for my last meal as I’ve found I sleep better afterwards. The worst nights of sleep I’d have during my prep were during my low carb days. Brutal.
Which supports the idea that blood glucose is running down, with bad consequences, during sleep. Even more telling was what someone else said:
Why does this happen to me? Before I was eating 2 cups of milk and a banana right before bed and would sleep fine. In the past few days I’ve tried to switch to 1 cup cottage cheese and 2 tbsp natty peanut butter. I’ve figured out this is why these past few nights I’ve had much more trouble sleeping and have had to resort to taking more OTC sleep aids. Then I’ll still wake up in middle of the night and can’t fall back asleep so I end up having a peanut butter and jelly sandwich and a cup of milk and 20 min later fall back asleep and sleep fine through the rest of the night.
Bedtime Snack A (2 cups of milk, banana): Good sleep. Bedtime Snack B (1 cup cottage cheese, 2 T peanut butter): bad sleep. There are hundreds of differences between the two snacks but one is that A, because of the banana, has about 6 g glucose and 6 g fructose (plus 3 g sucrose) and B has neither glucose nor fructose (nor sucrose). Stuart and I and several others have found that one tablespoon of honey (20 g) at bedtime greatly improves sleep. That much honey has about 8 g glucose and 8 g fructose. This is excellent evidence that it is the glucose and fructose in bedtime honey that improve sleep. Further evidence is that a snack with lots of sucrose (jelly) also produces good sleep.