Poor diet and cancer risk

Can unhealthy eating give you cancer?

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What you eat can have a big impact on your risk of developing cancer.

One of the biggest risk factors for cancer is being overweight or obese. Eating 'fast foods' (such as chips and fried chicken) or other processed foods that are high in fat and sugar (like chocolate, crisps and biscuits) can make you gain weight, and there is strong evidence that being overweight or obese is a cause of 12 types of cancer.

However, diets that are high in plant foods – such as fruit, vegetables, wholegrains and beans – can help you stay a healthy weight, and may also protect against certain cancers.

Benefits of eating more fibre

Diets rich in fibre (eg wholegrains, vegetables and fruit) can protect against bowel cancer. This may be because fibre helps to move food more quickly through the bowel.

There is also strong evidence that eating a fibre-rich diet that is high in wholegrains can protect against weight gain, being overweight and obese, which are linked to an increased risk of 12 cancers. This makes it one of the most important ways to help protect against cancer.

Benefits of eating fruit and vegetables

Vegetables and fruit can protect against cancers of the mouth, throat and digestive tract.

Vegetables and fruit provide your body with vitamins, minerals and other substances known as phytochemicals, which might help protect cells in the body from damage that may lead to cancer. Different types of vegetables and fruit contain different phytochemicals, so it is best to eat a variety every day.

cancer prevention icon for fast foodOur recommendation is to limit 'fast foods' and other processed foods high in fat, starches or sugars – find out how

cancer prevention icon for wholegrainOur recommendation is to enjoy more wholegrains, vegetables, fruit and beans – find out how 

Do we eat too much fat and sugar?

This table shows the recommended proportion of food energy that should be made up of fat, saturated fat and free sugars, compared to the proportion of food energy that is made up of these nutrients in the UK population, on average.

  % of food energy, by age group
Recommendation (% of food energy) 4–10 11–18 19–64 65+
Fat  <35% 33.4 33.9 34.7 34.9
Saturated fat <11% 13 12.4 12.5 13.8
Free sugars <5% 13.5 14.2 11.7 11.5

Figures from 2014–16

How many portions of vegetables and fruit do we eat?

We should all aim to eat at least 5 portions of fruit and vegetables a day. The table below shows that most of us are not reaching these recommendations.

Age group Average fruit and vegetable portions consumed per day % of people achieving 5 A DAY
11–18 2.7 8
19–64 4.2 31
65 and over 3.9 26

Figures from 2014–16. One portion is equivalent to 80g.

On the blog: diet and nutrition

Statistics on high-calorie foods and fruit & vegetables come from the National Diet and Nutrition Survey results from Years 7 and 8 (combined) of the Rolling Programme (2014/2015 – 2015/2016). Information on food portion sizes comes from the Ministry of Agriculture, Fisheries and Food's Food Portion Sizes, second edition.