What are the 7 classes of food and their sources?

October 26, 2025 •

3 min read

According to the Centre for Health Protection, food nutrients can be classified into 7 major groups. Knowing what are the 7 classes of food and their sources is fundamental to understanding how to create a balanced diet that supports overall health and well-being.

Quick Summary

This article outlines the seven fundamental classes of nutrients essential for the human body, detailing their primary functions and common food sources for a complete dietary understanding.

Key Points

Carbohydrates: The body's main energy source, sourced from grains, potatoes, and fruits.
Proteins: Essential for building and repairing tissues, found in meat, fish, eggs, and legumes.
Fats: Provide concentrated energy and aid in absorbing certain vitamins, available in nuts, seeds, and oils.
Vitamins & Minerals: Required in small amounts for regulating body functions and protecting against disease, sourced from fruits, vegetables, and dairy.
Dietary Fibre: Promotes a healthy digestive system, primarily from whole grains, fruits, and vegetables.
Water: Crucial for hydration, transporting nutrients, and regulating temperature.
Balanced Diet: The key to optimal health is consuming a mix of all seven classes of food in appropriate proportions.

The Foundation of a Balanced Diet

Understanding the fundamental components of our food is the first step toward building a healthy and balanced diet. Each of the seven food classes plays a distinct and crucial role in bodily functions, from providing energy to repairing tissue and fighting off disease. These classes are broadly divided into macronutrients, which we need in larger quantities, and micronutrients, required in smaller amounts. A diverse diet that incorporates foods from all these groups ensures the body has everything it needs to function optimally.

1. Carbohydrates

Carbohydrates are the body's primary and most efficient source of energy. The digestive system breaks them down into glucose, which fuels our cells, muscles, and central nervous system. They are categorized as simple or complex.

Sources: Grains, root vegetables, fruits, legumes, and cereals.

2. Proteins

Proteins are essential for the growth, repair, and maintenance of all body tissues. They are made of amino acids.

Sources: Meat, poultry, fish, eggs, dairy products, legumes, nuts, and seeds.

3. Fats (Lipids)

Fats are a concentrated source of energy, vital for insulating organs, regulating temperature, and absorbing fat-soluble vitamins. Healthy fats support brain function.

Sources: Nuts, seeds, vegetable oils, avocados, and fatty fish.

4. Vitamins

Vitamins are organic compounds needed in small quantities to regulate bodily processes. They help protect against disease and maintain healthy vision, skin, and bones. They are fat-soluble (A, D, E, K) or water-soluble (B-complex and C).

Sources: Various fruits, vegetables, dairy products, eggs, and nuts.

5. Minerals

Minerals are inorganic elements critical for functions like forming bones and teeth, nerve transmission, and muscle contraction. They work with vitamins for overall health.

Sources: Milk and dairy (calcium), red meat and leafy greens (iron), iodized salt (iodine), nuts and whole grains (various minerals).

6. Dietary Fibre

Fibre is the indigestible part of plant foods that aids healthy digestion. It prevents constipation and helps control blood sugar.

Sources: Whole grains, fruits, vegetables, legumes, and nuts.

7. Water

Water is the most abundant and essential nutrient, making up about 60% of body weight. It's crucial for transporting nutrients, regulating temperature, and flushing waste.

Sources: Drinking water, fruits, vegetables, and beverages.

Comparison of Macronutrients vs. Micronutrients

To help visualize the difference, the following table compares the main characteristics of macronutrients and micronutrients.


Feature	Macronutrients	Micronutrients
Function	Provide energy, building blocks for tissues.	Regulate body processes, protect against disease.
Required Amount	Large quantities (grams).	Small quantities (milligrams or micrograms).
Components	Carbohydrates, Proteins, Fats.	Vitamins, Minerals.
Energy Contribution	High (e.g., 4 kcal/g for carbs/protein, 9 kcal/g for fat).	None, but assist in energy metabolism.
Examples	Bread, meat, oil.	Leafy greens, citrus fruits, milk.

Creating a Balanced Plate

Combining these seven classes into a balanced diet is key. This means ensuring your plate features a variety of foods to cover all nutritional bases. Instead of focusing on just one type of nutrient, aim for a mix of complex carbohydrates, lean proteins, healthy fats, and a large portion of fruits and vegetables to supply a spectrum of vitamins, minerals, and fibre. Always remember to stay hydrated with plenty of water throughout the day. Creating mindful eating habits and understanding your body's needs is crucial for long-term health.

For more information on balancing your meals, you can refer to the official recommendations and guidelines, like those provided by the Centre for Health Protection(https://www.chp.gov.hk/en/static/100022.html).

Conclusion

In summary, the seven classes of food—carbohydrates, proteins, fats, vitamins, minerals, fibre, and water—are the fundamental components of any healthy diet. Each serves a unique and indispensable function, and getting a balanced intake of all of them is crucial for maintaining proper bodily function, energy levels, and long-term health. By making informed food choices based on these classes and their sources, you can build a more resilient and vibrant body.

Frequently Asked Questions

The primary function of carbohydrates is to provide the body with energy to carry out daily activities. The body breaks down carbohydrates into glucose, which is the main fuel source for the brain and muscles.

Protein is important for building and repairing body tissues, producing enzymes and hormones, and supporting immune function. It is made of amino acids, which are the building blocks for cells.

No, not all fats are unhealthy. While some fats, like trans fats, should be limited, healthy fats from sources like nuts, seeds, and avocados are essential for energy storage, absorbing vitamins, and overall cell function.

Macronutrients (carbohydrates, proteins, and fats) are needed in large quantities and provide energy. Micronutrients (vitamins and minerals) are required in small amounts for regulating body processes and protecting against disease, and they do not provide energy.

Water is essential for hydration, regulating body temperature, and transporting nutrients and waste products throughout the body. It is the most abundant substance in the human body and vital for survival.

Good sources of dietary fibre include whole grains, fruits, vegetables, legumes, and nuts. Fibre helps promote healthy digestion and prevent constipation.

To ensure your diet includes all seven classes, focus on eating a variety of foods from different food groups. Prioritize whole foods like fruits, vegetables, whole grains, lean proteins, and healthy fats, and remember to drink plenty of water.