The Digestive Process: How Food Is Digested in the Stomach
Eating and drinking are such routine parts of life that we rarely stop to think about what happens afterward. Yet, inside your body, every bite sets off a carefully coordinated process designed to pull out the nutrients and energy you need and dispose of the rest.
Initiating the Digestive Process
The moment you chew and swallow, your body launches into action. One of the key players here is peristalsis, a wave-like motion created by involuntary muscles. This motion pushes food down your esophagus and through the digestive tract. “You might not feel it happening, but if you could watch it on an X-ray, it would look a bit like an ocean wave moving food from one organ to the next”, says PIH Health Gastroenterologist Preeya Goyal.
Food travels from your throat down the esophagus, eventually reaching the stomach through a muscular gateway called the lower esophageal sphincter. This ring-shaped muscle opens to let food in, then closes to keep it there.
Inside the Stomach
Although it’s easy to think of the stomach as just a soft, hollow pouch, it’s a highly active organ with a very specific job: breaking food down.
It does this in several ways:
- First, the stomach relaxes and expands to accommodate the incoming meal
- Then, powerful digestive juices and enzymes get to work on the food. “These substances are strong enough to dissolve other tissues in the body, which is why the stomach has a thick mucus lining to protect itself’, explains Dr. Goyal.
- Muscles in the stomach churn the food, mixing it thoroughly with these digestive juices to form a semi-liquid substance
This part of digestion is where your body starts to transform what you ate into usable energy.
How Digestion Varies by Food Type
Not all foods are digested at the same pace. For example:
- Carbohydrates are typically digested the fastest, which is why they’re often recommended for a quick energy boost
- Proteins take longer to process
- Fats take the longest of all
- Zero-calorie liquids like water pass through the stomach quickly
Moving on to the Small Intestine
Once your stomach has finished its part of the job, it sends the partially digested food into the duodenum, the first section of the small intestine. From here, the liver and pancreas take over, contributing their digestive juices to further break down the food and extract nutrients.
Dr. Goyal emphasizes that though digestion may seem simple on the surface, it’s a finely tuned system that works silently in the background every time you eat. Learn how PIH Health can help by visiting PIHHealth.org/Digestive, or find a PIH Health Gastroenterologist near you at PIHHealth.org/Doctor.
Preeya Goyal MD
Preeya Goyal MD is a fellowship-trained gastroenterologist with expertise in esophageal and anorectal motility, which focuses on how things move through the gastrointestinal tract. Dr. Goyal was attracted to gastroenterology very early in her medical training. She is a member of the American College of Gastroenterology, American Gastroenterological Association and American Society of Gastrointestinal Endoscopy. Dr. Goyal was born and raised in California and is very happy to have the opportunity to stay close to her large family. She enjoys traveling, tennis, dancing, painting, trying new restaurants and spending time with friends and family in her free time.
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