What are carbohydrates, where do we get them, and why does the body need them?
Carbohydrate as a macronutrient, sugars, starch and dietary fibre (NSP), their sources and functions, free and intrinsic sugars, and the effects of too much or too little carbohydrate.
A focused CCEA GCSE Food and Nutrition answer on carbohydrates, covering sugars, starch and dietary fibre, their sources and functions, free versus intrinsic sugars, and the effects of eating too much or too little.
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What this dot point is asking
CCEA wants you to know what carbohydrates are, the difference between sugars, starch and fibre, where each is found, what they do in the body, the idea of free (added) sugars, and the effects of eating too much or too little.
What carbohydrates are
Sugars and starch
A useful contrast: sugars give a fast burst that does not last, while starch gives lasting energy that keeps you going and feeling full.
Free and intrinsic sugars
| Type of sugar | Meaning | Examples |
|---|---|---|
| Free (added) sugars | Sugars added to food or in syrups and juices | Table sugar, sweets, fizzy drinks, honey |
| Intrinsic sugars | Sugars locked inside the cells of foods | Whole fruit, vegetables, milk (lactose) |
The advice to "cut down on sugar" really means free sugars, because they add energy but few other nutrients (so-called empty calories) and harm teeth.
Dietary fibre (NSP)
Fibre prevents constipation, helps you feel full (aiding weight control), and helps prevent bowel disorders such as bowel cancer. Good sources are wholemeal bread, wholegrain cereals, brown rice, fruit, vegetables, beans and pulses.
Functions of carbohydrate
The main job of carbohydrate is to provide energy for movement, warmth and body processes. Spare carbohydrate is stored in the liver and muscles as glycogen, and any excess beyond that is converted to fat. Fibre, although a carbohydrate, works to keep the digestive system healthy rather than to give energy.
Too much and too little carbohydrate
Eating too much carbohydrate, especially free sugar, means excess energy stored as fat, leading to obesity and raising the risk of type 2 diabetes; sugary food also causes tooth decay. Eating too little carbohydrate leaves the body short of energy, so it breaks down fat and protein instead, causing tiredness and weight loss, and too little fibre causes constipation.
Examples in context
- Example 1. Why athletes "carb-load"
- Before a long event, athletes eat extra starchy carbohydrate such as pasta to build up glycogen stores in the muscles, giving a steady energy supply during exercise. This shows carbohydrate's main function (energy) matched to a group with high energy needs.
- Example 2. Sugar and tooth decay
- Bacteria in the mouth feed on free sugars and produce acid that attacks tooth enamel, causing dental caries. Sipping fizzy drinks throughout the day keeps the teeth bathed in acid. This is the direct link CCEA wants between free sugars and dental health.
- Example 3. Reading "of which sugars" on a label
- A nutrition label lists total carbohydrate and, underneath, "of which sugars". A high "of which sugars" figure on a cereal warns a shopper it is high in sugar, helping them choose a lower-sugar option. This connects carbohydrate to food labelling and being an effective consumer.
Try this
Q1. Name two foods that are good sources of starchy carbohydrate. [2 marks]
- Cue. Bread, pasta, rice, potatoes or breakfast cereal (any two).
Q2. Explain one reason we are advised to eat more fibre. [2 marks]
- Cue. It adds bulk to keep food moving through the gut and prevents constipation (or helps prevent bowel disorders).
Exam-style practice questions
Practice questions written in the style of CCEA exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
CCEA past-style6 marksExplain the difference between starchy carbohydrates and sugars, and discuss why we are advised to base meals on starchy foods and cut down on free sugars.Show worked answer →
Six marks: the two types, their sources, and the health advice.
Starchy carbohydrates (complex carbohydrates) are found in bread, pasta, rice, potatoes, cereals and oats. They release energy slowly and steadily, helping you stay full longer, and wholegrain versions also provide fibre.
Sugars (simple carbohydrates) are found in table sugar, sweets, fizzy drinks, cakes and biscuits. Free (added) sugars give a quick burst of energy but few other nutrients, so they are called empty calories.
We are advised to base meals on starchy foods, especially wholegrain, because they give lasting energy and fibre. We should cut down on free sugars because they cause tooth decay and, if eaten in excess, are stored as fat, contributing to obesity and type 2 diabetes.
Markers reward the slow/quick energy contrast, named sources, and links to tooth decay and obesity.
CCEA past-style4 marksState two functions of dietary fibre (NSP) and name two good sources.Show worked answer →
Four marks: two functions and two sources.
Functions: fibre adds bulk to food, which the muscles of the gut push against, keeping food moving and preventing constipation; it makes you feel full, which helps control weight; it helps prevent bowel disorders such as bowel cancer.
Sources: wholemeal bread, wholegrain cereals, brown rice, fruit and vegetables, beans and pulses.
Markers accept any two correct functions and two valid sources.
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