The short answer is yes -- your stomach can digest food within hours. Unless you have a condition such as a nervous disorder or complications from stomach surgery, then food tends to move through the stomach in around two hours. If food sits in your stomach for longer than four hours at a time, you may have a condition such as gastroparesis and should consult your doctor.
When you swallow food, it travels down your throat through a tube called the esophagus. The food arrives at your stomach mixed with saliva in a small lump called a bolus. Enzymes in the saliva already start to break down the food for digestion. Once in the stomach, hydrochloric acid and more digestive enzymes break the food down. The acid in the stomach is strong -- around pH 1. This helps digest the food as quickly as possible, avoiding problems that might occur by allowing the food to sit and rot in the stomach.
Muscles in the stomach help squeeze digested food into the small intestine a little at a time through a process called peristalsis. The food spends two to four hours in the stomach. The amount of food, type of food and amount of water you drink all affect the duration of digestion. From entering your mouth to passing as a stool, food may spend between 24 and 72 hours in your digestive system overall.
Some foods may take longer to digest than others. High-fat foods for example may take up to four hours to break down in the stomach, according to Net Wellness, a health information website run by a consortium of universities. The same applies to protein-rich foods. Starchy foods break down faster. Similarly, mushy foods such as soups or pulped banana digest faster because they're already partly broken down when they enter the stomach. Chewing your food for longer before swallowing helps food break down quicker and prevents indigestion.
In people with gastroparesis, food stays in the stomach too long because the vagus nerve stops working. Issues arise when the food starts to ferment, causing gassy buildup or bacterial infection. Food may also turn into hard chunks that won't easily work through the digestive tract. Several related conditions can trigger gastroparesis, but it's a common result of Type 1 diabetes. Symptoms include feeling full soon after you start eating, weight loss, nausea and a sensitive, bloated belly.