Our circadian rhythm—the natural waking and sleep cycle—is closely linked to our gastrointestinal tract. Part of this cycle is influenced by when you eat and how much. If you eat too much in the evening, your body cannot digest it all before bedtime, which can lead to bloating and gas. Learning how to time your meals with your periods of sleep can even help you get to sleep faster. For example, consuming foods rich in the amino acid tryptophan can increase your melatonin, which promotes relaxation.