Food & Nutrition

Humans must eat regularly to survive. Food provides the energy and raw materials the body needs to function, grow, and repair itself.

What is Food?

Food is any edible substance that provides nutritional value. It comes from:

Plants — fruits, vegetables, grains, legumes, nuts, seeds
Animals — meat, fish, poultry, eggs, dairy
Fungi — mushrooms
Processed combinations — packaged foods created by combining many ingredients

Humans eat food by chewing it with their teeth and swallowing it. It is then digested (How Your Body Works).

The Macronutrients

Three main categories of nutrients provide energy (measured in calories):

Macronutrient	Found In	Function
Carbohydrates	Bread, pasta, rice, fruit, sugar	Primary energy source
Proteins	Meat, eggs, beans, nuts	Building and repairing tissue
Fats	Oils, butter, nuts, fatty meats	Energy storage, hormone production, brain function

All three are necessary. Extreme restriction of any one causes problems.

Micronutrients

Vitamins and minerals are needed in small amounts:

Vitamin C — immune function; found in citrus fruits
Vitamin D — bone health; produced by skin in sunlight, found in fatty fish
Iron — blood; found in meat, spinach, legumes
Calcium — bones and teeth; found in dairy, leafy greens
B12 — nerve function; found almost exclusively in animal products (important for vegans)

Meals and Timing

🚩 Meal culture varies enormously:

Most humans eat 2–3 meals per day, typically:

Breakfast — morning meal, often lighter
Lunch — midday meal
Dinner/Supper — evening meal, often the largest

Some cultures eat 4–5 smaller meals. Some fast periodically for religious or health reasons.

A Healthy Diet: The Basics

A well-balanced diet generally includes:

Plenty of vegetables and fruits (aim for variety of colors)
Whole grains (brown rice, oats, whole wheat) over refined grains (white bread, white rice)
Lean protein (beans, fish, poultry, eggs)
Healthy fats (olive oil, nuts, avocado)
Limited added sugar, salt, ultra-processed foods, and alcohol

Food and Culture

Food is deeply cultural. It is tied to identity, religion, celebration, and family.

🚩 Key dietary considerations across cultures:

Halal — Islamic dietary law; prohibits pork and alcohol, requires specific slaughter methods
Kosher — Jewish dietary law; prohibits pork and shellfish, separates meat and dairy
Vegetarian — no meat; common in Hinduism and as a personal choice globally
Vegan — no animal products at all
Fasting — periodically not eating; practiced in Islam (Ramadan), Christianity (Lent), Judaism (Yom Kippur), and others

When sharing a meal with humans, asking about dietary restrictions before serving food is considered polite and thoughtful.

Hunger and Fullness

The body signals hunger (need for food) and fullness (enough food). Humans in wealthy societies often override these signals due to emotional eating, distraction, or food availability. This contributes to obesity, which is a significant health issue in many countries.