If people are advised to take an "energy boost", so to speak, they're advised to take in sugary substances. Yet, the thing is - all nutrients are absorbed through the small intestines. But does food stay in the stomach for a number of hours? And then, what factors control the passage of food into the intestines? Are these factors selective to a particular type of food (that is, are they more receptive to food that is broken up?) And in that case, do some nutrients (simple sugars, for example) quickly pass through the stomach and into the intestines? What of drugs and pills? How long do they need to be digested before absorption?