1 Basics of Nutrition
1. Macronutrients — The Body’s Primary Fuel and Building Blocks
Macronutrients are nutrients needed in large amounts and provide energy (calories):
| Macronutrient | Main Functions | Calories per gram | Found In |
|---|---|---|---|
| Carbohydrates | Main source of energy | 4 kcal | Grains, fruits, legumes, vegetables |
| Proteins | Builds and repairs tissue; enzymes, hormones | 4 kcal | Meat, dairy, legumes, eggs, tofu |
| Fats | Energy storage, hormones, cell membranes | 9 kcal | Oils, nuts, seeds, avocado, fish |
| Water | Hydration, transport, temperature regulation | 0 | All foods and fluids |
| Fiber (carb) | Digestive health, blood sugar regulation | 0 (indigestible) | Whole grains, vegetables, legumes |
Approximate daily recommendations (based on a 2000 kcal diet):
- Carbs: 45–65% of daily calories → ~225–325 g
- Protein: 10–35% → ~50–175 g (average need: ~0.8–1.2 g/kg body weight)
- Fat: 20–35% → ~44–78 g
2. Micronutrients — The Small Players with Big Roles
Micronutrients are nutrients needed in small amounts, but are essential for health, growth, and cellular function. They don’t provide energy, but they enable your body to function.
Vitamins (organic compounds): Support immunity, energy metabolism, skin, vision, nerve function, blood health, and more.
Minerals (inorganic elements): Support bone structure, nerve transmission, fluid balance, oxygen transport, and enzyme activity.
Examples with daily needs and common sources:
| Micronutrient | Daily Dose | Common Sources | Function |
|---|---|---|---|
| Vitamin A | 700–900 µg | Carrots, liver, sweet potato | Vision, skin, immune system |
| Vitamin C | 75–90 mg | Citrus, peppers, broccoli | Antioxidant, collagen synthesis |
| Vitamin D | 15–20 µg (600–800 IU) | Sunlight, fatty fish, fortified milk | Bone health, calcium absorption |
| Vitamin B12 | 2.4 µg | Meat, fish, dairy, eggs | Nerve function, red blood cells |
| Iron | 8–18 mg | Red meat, spinach, legumes | Oxygen transport |
| Calcium | 1000–1200 mg | Dairy, tofu, leafy greens | Bones, muscle contraction |
| Magnesium | 310–420 mg | Nuts, whole grains, leafy greens | Muscle and nerve function |
| Zinc | 8–11 mg | Meat, legumes, seeds | Immune function, wound healing |
| Iodine | 150 µg | Iodized salt, seafood, dairy | Thyroid hormone production |
These values vary slightly depending on age, sex, and life stage.
3. Food Groups — How Nutrients Appear in Real Foods
Food groups are practical categories of whole foods that provide a variety of macro- and micronutrients.
| Food Group | Main Nutrients Provided |
|---|---|
| Fruits | Carbohydrates, fiber, vitamin C, potassium |
| Vegetables | Fiber, vitamins A/K/C, magnesium, antioxidants |
| Grains | Carbohydrates, B-vitamins, fiber (whole grains) |
| Protein Foods | Protein, iron, B12, zinc, fats (animal or plant) |
| Dairy | Protein, calcium, vitamin D, B12 |
| Fats & Oils | Fats (esp. unsaturated), vitamin E |
A balanced diet combines all food groups, ensuring you get:
- All macronutrients for energy and structure
- All micronutrients for regulation and support
4. What a Healthy Diet Looks Like (In Practice)
- Half your plate = vegetables and fruits
- One quarter = whole grains (rice, oats, bread)
- One quarter = protein foods (legumes, meat, tofu, eggs)
- A small amount of healthy fats (olive oil, nuts, seeds)
- Plenty of water
- Some dairy or dairy alternatives
- Variety over time ensures full nutrient coverage