Biology
Nutrition & nutrients
What is in your food and what does your body need it for? Energy, building blocks, and the right mix.
What you need first
After sports you are hungry, and in the morning before school a breakfast helps you wake up. Food is the fuel of your body, but it is more than that: from food your body also builds new cells and stores reserves. For this to work well, your body needs different nutrients, each with its own job.
The three main nutrients
There are three large nutrient groups. Carbohydrates, as in bread, pasta, and rice, supply quick energy, and sugar counts as one of them too. Protein is found in meat, eggs, and beans and is an important building material for your cells and muscles. Fat from oil, nuts, and butter is a strong energy store: of the three groups it delivers the most energy per gram.
- Carbohydrates 50%quick energy: bread, pasta, rice
- Protein 25%building block for muscles: eggs, beans, fish
- Fat 25%energy store: oil, nuts, butter
Simplified model: the percentages are mass shares in 100 g of food, carbs and protein give 4 kcal/g, fat 9 kcal/g. It is not a meal plan.
More than just energy
Besides the three main nutrients, your body needs vitamins and in small amounts, for example for bones, blood, and defence. And it needs water, because a large part of your body is made of it. What matters is the mix: a balanced diet contains a bit of everything instead of just one single kind. The energy in food is measured in kilocalories, kcal for short. Carbohydrates and protein each supply about 4 kcal per gram, while fat supplies about 9 kcal per gram.
Exercises
0 of 6 solvedTime to try it yourself. You can't break anything, every attempt counts.
Which nutrient is above all a building material for your cells and muscles?
Which nutrient delivers the most energy per gram?
How many main nutrient groups are there: carbohydrates, protein, and fat?
Match each main nutrient to its most important job.
About how many kilocalories does 1 gram of fat supply?
What matters is the mix: a … diet contains a bit of everything.
Where this leads