How does a poor diet cause ill health, and what diet-related conditions and intolerances should I know about?
Diet-related health: how poor diet causes obesity, cardiovascular disease, type 2 diabetes, tooth decay, bone health problems and some cancers, plus food allergies and intolerances and how diets are adapted.
A focused answer to the WJEC Food Preparation and Nutrition diet and good health topic on diet-related conditions, covering obesity, cardiovascular disease, type 2 diabetes, tooth decay, bone health and cancer risk, plus food allergies and intolerances and how diets are adapted.
Reviewed by: AI editorial process; not yet individually human-reviewed
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What this dot point is asking
You need to know how a poor diet causes ill health, the main diet-related conditions (obesity, cardiovascular disease, type 2 diabetes, tooth decay, bone problems and some cancers), the difference between a food allergy and an intolerance, and how diets are adapted.
How a poor diet causes ill health
The main culprits are eating too much saturated fat, salt, free sugar and energy, and too little fruit, vegetables and fibre. Over time this leads to several conditions.
The main diet-related conditions
- Obesity
- Caused by regularly taking in more energy than you use, so the excess is stored as fat. Obesity itself raises the risk of the conditions below and strains the joints.
- Cardiovascular disease (CVD)
- Too much saturated fat raises blood cholesterol, which builds up in and narrows the arteries; too much salt raises blood pressure. Together these increase the risk of heart disease and stroke.
- Type 2 diabetes
- Linked to obesity and a diet high in free sugars and energy; the body can no longer control blood glucose properly. It can often be reduced by losing weight and eating well.
- Tooth decay
- Caused by free sugars, which bacteria in the mouth turn into acid that attacks tooth enamel.
- Bone health problems
- Too little calcium and vitamin D weakens bones: rickets in children and osteoporosis (brittle bones) in later life.
- Some cancers
- A poor diet, obesity and too little fibre are linked to a higher risk of some cancers, including bowel cancer.
Reducing the risk
The dietary changes are the reverse of the causes:
- swap saturated for unsaturated fat,
- cut down on salt and free sugars,
- eat more fruit, vegetables and wholegrain fibre,
- control portion sizes and stay active to keep a healthy weight,
- get enough calcium and vitamin D for bones.
Food allergies and intolerances
- Allergy examples: nuts, shellfish, eggs. Sufferers must avoid the food completely and may carry an adrenaline pen. There are 14 allergens that must be declared on food labels.
- Intolerance examples: lactose intolerance (difficulty digesting milk sugar), causing bloating and stomach pain; coeliac disease is an immune reaction to gluten that damages the gut and needs a strict gluten-free diet.
Exam-style practice questions
Practice questions written in the style of WJEC exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
WJEC style6 marksExplain how a poor diet can lead to cardiovascular disease and type 2 diabetes, and suggest dietary changes to reduce the risk.Show worked answer →
A 6-mark question. Mark it for the link between diet and each condition, plus sensible changes.
A diet high in saturated fat raises blood cholesterol, which can build up in the arteries and narrow them, increasing the risk of cardiovascular disease (heart disease and stroke). Too much salt raises blood pressure, adding to that risk. A diet high in free sugars and energy, leading to obesity, raises the risk of type 2 diabetes, where the body cannot control blood glucose properly. To reduce the risk, swap saturated fats for unsaturated fats, cut down on salt and free sugars, eat more fruit, vegetables and wholegrain fibre, control portion sizes, and be active to maintain a healthy weight.
A top answer links saturated fat and salt to cardiovascular disease, and excess energy and sugar (via obesity) to type 2 diabetes, then gives matching dietary changes.
WJEC style4 marksExplain the difference between a food allergy and a food intolerance, giving an example of each.Show worked answer →
A 4-mark question. Award marks for the distinction and correct examples.
A food allergy is a reaction by the body's immune system to a particular food, which can be rapid and severe, sometimes life-threatening (anaphylaxis), for example a nut or shellfish allergy. A food intolerance does not involve the immune system; the body has difficulty digesting a food, causing unpleasant but not life-threatening symptoms such as bloating and stomach pain, for example lactose intolerance (difficulty digesting the sugar in milk). People with an allergy must avoid the food completely and may carry an adrenaline pen.
Markers reward: allergy involves the immune system and can be severe or life-threatening with an example; intolerance does not involve the immune system and is not life-threatening with an example.
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Sources & how we know this
- WJEC Eduqas GCSE Food Preparation and Nutrition specification (from 2016) — WJEC Eduqas (2016)