What is the process of getting and eating food called? Ingestion and Nutrition Explained

November 18, 2025 •

2 min read

The human digestive tract is a complex, 30-foot long tube where food is processed. The initial stage of this journey, including getting and eating food, is known as ingestion, which is a key part of the larger, multi-step process of obtaining nutrition.

Quick Summary

The act of taking food into the body is called ingestion, but the complete multi-step process of obtaining and utilizing food is known as nutrition, which includes digestion, absorption, and elimination.

Key Points

Ingestion vs. Nutrition: Ingestion is the act of putting food into the mouth, while nutrition encompasses the entire process of obtaining and using food for energy, growth, and repair.
The Digestive Journey: The process of nutrition involves a sequence of stages: ingestion, mechanical and chemical digestion, absorption, assimilation, and finally, elimination.
Mechanical Breakdown: Mastication (chewing) and the churning action of the stomach physically break down food, increasing its surface area for better enzymatic action.
Chemical Breakdown: Enzymes in saliva, gastric juices, and pancreatic juices chemically dismantle complex molecules like carbohydrates, proteins, and fats into simpler, usable building blocks.
Nutrient Absorption: The small intestine is the primary site where nutrients are absorbed into the bloodstream and lymphatic system to be transported to cells throughout the body.
Gut Bacteria's Role: The microbiome in the large intestine assists in the final stages of digestion by fermenting undigested food and producing vital vitamins.

Ingestion: The Initial Act

Ingestion is the specific biological term for taking food or liquid into the body through the mouth. It is the very first step of the digestive system's complex process and is a conscious, voluntary action.

The Mechanics of Ingestion

Ingestion in humans involves several steps that prepare food for digestion. It begins with sensory input like sight and smell, stimulating saliva production. Chewing, or mastication, uses teeth, tongue, and jaw muscles to break down food into smaller pieces, increasing the surface area for enzymes. Saliva mixes with food, starting carbohydrate digestion with salivary amylase. The tongue forms a bolus, which is then swallowed (deglutition), moving it into the esophagus while the epiglottis covers the trachea.

Nutrition: The Complete Biological Process

While ingestion is the act of eating, nutrition is a broader process by which organisms obtain and use food for life, growth, and development. Ingestion is the first of several stages in nutrition:

The Stages of Food Processing

Ingestion: Taking food into the body via the mouth.
Digestion: Breaking down food mechanically and chemically into smaller molecules.
Absorption: Moving digested food molecules from the GI tract into the blood or lymph. This primarily occurs in the small intestine.
Assimilation: Transporting absorbed nutrients to cells for energy, growth, and repair.
Elimination (Egestion): Removing undigested waste as feces.

Digestion Explained: Mechanical vs. Chemical

Digestion involves both mechanical and chemical processes:


Feature	Mechanical Digestion	Chemical Digestion
Mechanism	Physical breakdown of food.	Enzymatic breakdown of molecules.
Location	Mouth, stomach, small intestine.	Mouth, stomach, small intestine.
Key Agents	Teeth, tongue, muscle contractions.	Enzymes, acids, bile.
Purpose	Increase surface area.	Break chemical bonds for absorption.

The Digestive System's Supporting Players

Accessory organs aid digestion and nutrition:

Salivary Glands: Produce saliva with enzymes.
Liver: Produces bile and processes nutrients.
Gallbladder: Stores and concentrates bile.
Pancreas: Secretes digestive enzymes and bicarbonate.

The Role of Gut Flora

The large intestine's microbiome breaks down indigestible matter like fiber and produces vitamins. This fermentation is crucial for health and nutrient absorption.

Conclusion

Ingestion is the initial act of eating, while nutrition is the complete process of obtaining and using food. This involves ingestion, digestion (mechanical and chemical), absorption, assimilation, and elimination. Accessory organs and gut flora are also vital for this complex system.

For a comprehensive overview of the digestive process, including animations and videos, you can explore resources from reputable sources such as the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).(https://www.niddk.nih.gov/health-information/digestive-diseases/digestive-system-how-it-works)

Frequently Asked Questions

The very first step of the digestive process is ingestion, which is the act of taking food into the body through the mouth.

Ingestion is the act of consuming food, whereas digestion is the subsequent mechanical and chemical breakdown of that food into smaller, absorbable molecules.

After ingestion, the food is chewed and mixed with saliva to form a bolus. It then travels down the esophagus to the stomach, where further mechanical and chemical digestion begins.

Saliva moistens food to make it easier to swallow and contains salivary amylase, an enzyme that starts the chemical breakdown of starches while the food is still in the mouth.

Most of the absorption of nutrients takes place in the small intestine, where digested food molecules pass into the bloodstream through the intestinal walls.

The final stage of food processing is elimination, also known as defecation or egestion. This is the process of removing undigested waste products from the body.

Yes, swallowing is a key part of ingestion, propelling the chewed food (bolus) from the mouth into the esophagus.