Nutrients in Food [Types and Functions]

How Foods Are Classified by Function

Foods can be grouped in different ways. One common way is by the function they perform in our body.

Sometimes we feel confused and don’t know what to eat. So… how are foods classified based on their function?

Types of Nutrients and their Functions:

• Energy-yielding foods
• Body-building foods
• Regulatory and protective foods

Knowing the function of different foods doesn’t just help with school assignments! Understanding what your body needs helps you choose a diet that’s both convenient and healthy. That way, your body can do all the amazing things it was designed to do.

“We are what we eat.”
Food is the fuel for your body. But what does that really mean?

Our body needs energy to do everyday things—like walking, running, breathing, and even staying warm. That energy comes from the nutrients in the food we eat.

Through a process called oxidation (or “combustion”), our body transforms food into energy. This energy turns into heat and movement, helping us stay active and alive.

What Is Food? (Definition for Kids)

Food includes natural substances (like apples) and processed ones (like bread). When we eat them, they give our body the energy and materials it needs to grow, move, and stay healthy.

What Are Nutrients?

Nutrient Classifications

Nutrients are chemical compounds found in food. They’re what make food useful to the body—they provide energy, build and repair tissues, and help regulate all our body functions.

Types of Nutrients and their Functions

The main types of nutrients are:

• Carbohydrates
• Proteins
• Fats
• Vitamins
• Minerals
• Water

Energy Function

This function is mainly carried out by carbohydrates and fats.
Only when the body doesn’t get enough calories will it start using proteins as a source of energy.

Energy Foods

Energy foods are those that contain carbohydrates and fats as their main nutrients.

What Are Carbohydrates?

Carbohydrates are made of three elements: carbon, hydrogen, and oxygen.

Depending on their structure, carbohydrates are classified into:

• Monosaccharides: Made of a single carbon chain.
• Disaccharides: Made of two monosaccharides.
• Oligosaccharides: Made of 3 to 9 monosaccharides.
• Polysaccharides: Made of chains of 10 or more monosaccharides, which may be branched or not.

When carbohydrates are metabolized by the body, they release 4 calories (or kilocalories) per gram.

Let’s be accurate: food doesn’t actually “contain” calories. What it contains is potential energy. When the body metabolizes food, it releases energy.

That’s why energy-rich foods should be eaten in moderation and in amounts that match your personal daily needs.

For example, a baby and an athlete have very different energy requirements.
If you eat more energy than your body uses, the extra energy is stored—and that can lead to health problems like obesity.

What About Fats?

Fats (also called lipids) are also energy-rich nutrients.
When metabolized, they release 9 calories per gram, more than twice what carbohydrates provide!

Fun Fact: Is Water an Energy Food?

No!
Some sources may claim that water is an energy food, but that’s not true.

Energy foods provide calories, meaning they release energy when metabolized. Water doesn’t do that.

Even though water is essential for life, it doesn’t provide energy or calories. You should definitely drink plenty of it—but don’t confuse it with energy foods.

Read also: Water Cycle for kids

Some Foods Do NOT Provide Nutrients

That’s right—there are foods we eat just out of habit or for pleasure, and they don’t provide nutrients.
Some condiments, for example, fall into this category.

Healthy Energy vs. Empty Calories

Among energy-rich foods, some provide only what are known as “empty calories.”
This term is used by nutritionists to describe foods that offer calories but little to no nutrients.

On the other hand, healthy energy foods give you calories and important nutrients your body needs to function well.

⚠️ Consuming too many empty-calorie foods can harm your health. It can lead to weight gain and increase the risk of diseases like:

• Obesity
• Heart disease
• Diabetes
• Cancer

Read also: Five Basic Food Groups easy for kids and students

Examples of Energy Foods

1. Vegetable Oils and Fats

These provide 100% fat and lots of energy.

• Vegetable oils: Olive, avocado, sunflower, corn, grape seed, soybean, safflower, and others.
  They provide essential fatty acids (Omega-3 and Omega-6) and help the body absorb fat-soluble vitamins (A, D, E, and K).
• Animal fats: Butter, cream, cheese, milk, milk chocolate, sausages, bacon, and cold cuts.
• Pastry products and cookies: These combine fats and carbs, making them very energy-dense.
  ⚠️ Margarine, although it’s made from vegetable oils, contains harmful trans fats due to industrial hydrogenation. These fats are linked to health problems.

2. Cereals and Derivatives

Wheat, rice, corn, barley, rye, oats, flour, bread, pasta, cookies.
These are rich in carbohydrates and provide a lot of energy.

3. Legumes

Peas, chickpeas, broad beans, lentils, beans, soybeans.
They are energy foods and also provide protein.

4. Sugar

100% carbohydrate — 4 calories per gram. Pure energy, no nutrients.

5. Honey

Contains about 75% carbohydrates.

6. Sweets

Candy, dulce de leche, fruit jellies, sweet potato or quince paste — around 75% carbs on average.

7. Foods High in Simple Sugars

Fruit juices, sodas, candy.
Often only provide empty calories — sugar with little to no nutrients.

8. Starchy Vegetables

Potatoes, sweet potatoes, and other tubers have more carbohydrates than other vegetables.

9. Baked Goods and Pastries

Cakes, croissants, pastries combine flour, sugar, and butter — a powerful energy mix.

10. Nuts and Seeds

Walnuts, almonds, hazelnuts, pistachios.
Provide both energy and nutrients, especially healthy fats.

11. Various Meats

Meat provides protein and fat, which can be used for energy—only when carbs or fats are not available.
Proteins give 4 calories per gram, like carbohydrates, but the body prefers to use them for repair and growth.

Quick List: Energy Foods

• Olive oil, sunflower oil, avocado
• Rice
• Oatmeal
• Banana, grapes, figs
• Potato, sweet potato
• Chickpeas, lentils, beans, peas
• Walnuts, almonds, hazelnuts
• Pasta, noodles (like gnocchi or ravioli)
• Avocado

2. Body-Building Foods (Also Called Plastic Foods)

These foods are rich in protein and help your body grow and repair itself.

What Do Body-Building Foods Do?

Our bodies are constantly building new tissues and replacing old ones. This is called cell regeneration or cell replacement.

During growth (like from baby to teen), your body gets bigger and stronger by producing new cells. Even in adulthood, your body keeps renewing:

• Skin cells
• Red blood cells
• Wounded or damaged tissues

To do this, the body needs proteins, water, and minerals, which come from food.

Examples of Body-Building (Protein) Foods

Animal-based:

• Dairy (milk, cheese, yogurt)
• Eggs
• Meats (beef, chicken, pork, fish, cold cuts)

Milk and dairy products provide calcium, protein, and vitamins for healthy bones and teeth.
Meats, eggs, and fish offer high-quality proteins and are a source of vitamin B12.
Fish gives you essential fatty acids (like Omega-3), which your body can’t produce on its own.

Plant-based:

• Legumes (lentils, beans, chickpeas, soy)
• Whole grains (wheat, oats, corn)
• Nuts and seeds

🌱 Legumes and grains complement each other to form complete proteins.
🥜 Nuts are also rich in minerals and healthy fats.

Nutrients

Nutrients are substances that are naturally part of both our body and the food we eat.
When we don’t get enough of them—especially for a long time—our health can suffer, and we may develop deficiency diseases.

Types of Nutrients

Macronutrients

These are nutrients that the body needs in large amounts:

• Carbohydrates
• Fats
• Proteins

Micronutrients

Even though we need these in small amounts, they are just as important as macronutrients.
Micronutrients are:

• Vitamins
• Minerals

3. Regulatory Foods: Fruits and Vegetables

What Are Regulatory Foods?

Regulatory foods are those that contain vitamins and minerals.
These nutrients help control and support vital body functions, making sure everything in your body works as it should.

Regulatory Nutrients

Vitamins

• Needed in small quantities
• Help with growth, body maintenance, and reproduction
• Essential for life
• The body can’t make them, so we must get them from food

Minerals

• Needed in low amounts
• Support growth, cell maintenance, and overall health
• Like vitamins, they don’t provide energy, but they are still vital

There are two categories of minerals:

1. Major minerals (needed in larger amounts):
   • Calcium
   • Phosphorus
   • Sodium
   • Chlorine
   • Magnesium
   • Iron
   • Sulfur
2. Trace minerals or microminerals (needed in tiny amounts):
   • Zinc
   • Copper
   • Iodine
   • Chromium
   • Selenium
   • Cobalt
   • Molybdenum
   • Manganese
   • Fluoride

Where Do We Find These Nutrients?

You’ll find vitamins, minerals, and fiber mostly in fruits and vegetables.

That’s why it’s so important to include them in your daily meals—they help regulate your body and keep you healthy!