How can what we eat lead to diseases such as obesity, heart disease and diabetes, and how can diet help prevent them?
Describe the main diet-related diseases, their links to diet and lifestyle, and how they can be prevented through healthier choices
A simple, focused answer on diet-related diseases for N(A)-Level Nutrition and Food Science: obesity, heart disease, type 2 diabetes, high blood pressure, osteoporosis and anaemia, their links to diet and lifestyle, and how to prevent them.
Reviewed by: AI editorial process; not yet individually human-reviewed
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What this dot point is asking
SEAB wants you to describe the main diet-related diseases, explain how diet and lifestyle raise the risk of each, and suggest how they can be prevented. The big idea is that what we eat over many years, together with how active we are, strongly affects our health. The marks come from linking a specific dietary cause to a specific disease (for example too much saturated fat to heart disease) and from giving sensible, matched prevention advice.
The answer
Obesity
Obesity is having too much body fat, caused over time by energy in being greater than energy out, that is, eating more energy (especially from fatty and sugary food) than the body uses. Obesity is itself a starting point for other diseases. It is prevented by balancing energy intake with activity: smaller portions, less fatty and sugary food, more activity.
Coronary heart disease
Coronary heart disease happens when the arteries to the heart become narrowed by a build-up of fatty deposits. A diet high in saturated fat raises blood cholesterol, which speeds this build-up. It is reduced by eating less saturated fat (grill or steam instead of frying, trim fat, choose unsaturated oils) and staying active.
Type 2 diabetes
Type 2 diabetes is when the body can no longer control its blood sugar properly. It is linked to being overweight, a diet high in free sugar and inactivity. It is reduced by cutting free sugar, eating wholegrains for steady energy, losing excess weight and exercising.
High blood pressure
High blood pressure (hypertension) is linked to eating too much salt and to being overweight, and it raises the risk of heart attack and stroke. It is reduced by using less salt, eating fewer salty processed foods, and keeping to a healthy weight.
Osteoporosis
Osteoporosis is a disease of weak, brittle bones that break easily, linked to a long-term shortage of calcium (and vitamin D). It is reduced by eating enough calcium-rich foods (milk, cheese, tofu, small fish with bones) and getting enough vitamin D, especially while bones are still building.
Anaemia
Anaemia is a shortage of healthy red blood cells, often from too little iron, causing tiredness and a pale appearance. It is reduced by eating iron-rich foods (red meat, dark green leafy vegetables, beans) with a vitamin C food to aid absorption.
Examples in context
Example 1. Choosing a healthier hawker meal. Swapping a regular order of deep-fried chicken with white rice and a sweet drink for steamed fish with brown rice, extra vegetables and plain water cuts saturated fat and free sugar while adding fibre. Made a habit, this kind of choice lowers the risk of heart disease and type 2 diabetes, showing prevention through everyday food.
Example 2. Reducing salt to protect blood pressure. A person with high blood pressure who cuts back on salty foods such as instant noodle seasoning, salted fish and heavy soy sauce, and asks for less salt when ordering, reduces their salt intake. Lower salt helps bring blood pressure down, showing the direct link between a single dietary factor and a disease.
Try this
Q1. Explain how a diet high in saturated fat can lead to heart disease. [3 marks]
- Cue. Saturated fat raises blood cholesterol, which builds up in the arteries and narrows them, reducing blood flow to the heart.
Q2. Name the disease linked to too much salt and suggest one way to reduce the risk. [2 marks]
- Cue. High blood pressure (hypertension); reduce salt in cooking and eat fewer salty processed foods.
Q3. Suggest three changes to diet or lifestyle to reduce the risk of type 2 diabetes. [3 marks]
- Cue. Any three of: cut free sugar, lose excess weight, eat wholegrains and fibre, exercise regularly.
Exam-style practice questions
Practice questions written in the style of SEAB exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Original8 marksMr Raj is overweight, eats a lot of fried and sugary food, rarely exercises, and his doctor warns him about type 2 diabetes and heart disease. (a) Explain how his diet and lifestyle raise his risk of these diseases. (b) Suggest four changes to his diet and lifestyle to lower the risk. (Section C style)Show worked answer →
(a) Eating a lot of fried food (high saturated fat) raises blood cholesterol, which can clog the arteries and lead to heart disease. Eating a lot of sugary food and being overweight with little exercise raise the risk of type 2 diabetes, because the body becomes less able to control blood sugar. The excess energy from fatty and sugary food is stored as fat, causing the overweight that worsens both conditions.
(b) Any four of: eat less fried and fatty food and grill or steam instead; cut down on sugary drinks and snacks; eat more fruit, vegetables and wholegrains for fibre; reduce portion sizes to lose excess weight; exercise regularly; and reduce salt to help blood pressure.
What markers reward: linking saturated fat to cholesterol and heart disease and excess sugar plus weight to type 2 diabetes, and four genuine, separate diet or lifestyle changes that target these risks.
Original4 marks(a) Name the disease linked to eating too much salt. (b) Name the bone disease linked to a long-term lack of calcium. (c) State one diet change to reduce the risk of each. (Section B style)Show worked answer →
(a) High blood pressure (hypertension).
(b) Osteoporosis (weak, brittle bones).
(c) For high blood pressure: reduce salt by using less in cooking and choosing fewer salty processed foods. For osteoporosis: eat more calcium-rich foods such as milk, cheese, tofu and small fish with bones (and get enough vitamin D).
What markers reward: correctly naming high blood pressure for salt and osteoporosis for low calcium, and one realistic, correctly matched diet change for each.
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