Does sugar cause cancer growth?

Sugar (sucrose) is a type of carbohydrate and is an energy source used by the body. It’s found in many different types of foods including soft drinks, juices, cakes, biscuits and sweets.

Sugar is also found in products where you would not expect to find it. For example, it can be added to soups, sauces, ketchup, and ready meals. The ingredients list on the packaging will show if sugar has been added. Sugar can also occur naturally in food, such as the sugars in fruit and milk – however, we don’t need to cut down on these types of sugar – it’s the added sugar we should try to limit.

All types of sugar, like other carbohydrates, are broken down and then absorbed into the blood. Some sugars are absorbed into the blood faster than others. Sugar that is added to food and drinks is absorbed into the blood faster than sugars from whole foods such as fruit.

Is eating sugar bad when you have cancer?

There isn’t any evidence that eating a diet low in sugar affects cancer in a good or bad way. If you are having cancer treatment and are losing weight, carbohydrate-rich foods such as bananas, pasta and bread can be a good way of giving your body the extra energy it needs.

Otherwise, a diet high in added sugar can lead to weight gain and may lead to you becoming overweight or obese. There is strong evidence that being overweight or obese increases your risk of developing certain types of cancer.

Can you live without sugar?

Every cell in our body needs glucose. However, you don’t need to eat sugar to provide it as our bodies can make glucose from protein and fat. Any carbohydrates, including starchy carbohydrate foods (like pasta, bread and rice) and sugars in the diet, are converted to glucose. If you don’t eat enough carbohydrates, your body will use protein to make glucose. This can be protein from our food or protein from our own muscles. This can cause our strength and muscle to decrease, so it’s best to eat a balanced diet with the right amount of carbohydrates.

Fibre, vitamins and minerals are also found in many foods and drinks that contain carbohydrates such as fruit, vegetables, bread, grains, pulses, and milk and milk-based products (and plant-based milk) – all foods that form part of a healthy, balanced diet.

Our advice

The Government’s Eatwell Guide suggests that starchy carbohydrates such as bread, pasta, potatoes, and rice should make up a third of the food that we eat. People should choose wholegrain versions such as wholegrain pasta and bread if they are able to eat food that is high in fibre. Foods high in added sugar such as biscuits, cakes and fizzy drinks should be eaten less often and in smaller amounts.

If you have a poor appetite due to illness or treatment and have experienced unintentional weight loss, sugar can be useful to help you get enough calories to help you maintain a healthy weight.

> Read more about managing unintentional weight loss

> Should you avoid sugar if you have cancer?

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