Caffeine makes us feel more alert by blocking production of the chemicals in the brain that tell our bodies to sleep and increasing adrenaline. The stimulant affects everyone’s bodies differently.
Heavy foods that are spicy or fatty are tougher for the stomach to digest than lighter ones (like bananas or whole grains). And indigestion before bedtime makes it harder for your body to relax and drift off to slip.
Too much sugar in your diet has a direct effect on blood sugar levels, which very directly influence your energy levels throughout the day. sugar boosts energy levels quickly, but they crash quickly after that, too and affects your sleep.