Almonds are “the perfect bedtime snack,” Brief says. Not only do they (or a tablespoon of almond butter) contain protein, fat, and fiber that will stabilize your blood sugar, but the nuts also contain tryptophan and magnesium, which help to naturally lower the stress hormone cortisol, Brief explains. Low cortisol levels help you drift off to sleep. But in the morning they start to surge in order to wake you up. Like melatonin, cortisol also helps to regulate your circadian rhythm.