Obese and overweight people are in denial about the risks their girth poses to their health and many do not even want to lose weight, researchers said today.

The study by the charity Cancer Research UK found that 87% of obese people and 32% of those who are overweight failed to recognise how heavy they were, with many believing they were a normal weight.

The survey of 4,000 people found that half were overweight or obese but more than a quarter of that group (26%) had no desire to try to lose weight.

The charity found that nearly three-quarters (71%) of the obese and overweight respondents to the survey were unaware that their weight put them at increased risk of developing cancer.

Almost half did not believe that eating healthily could help reduce the risk of cancer, while almost two-thirds (64%) were unaware that regular exercise could also reduce the risk.

More than 80% did not know the importance of maintaining a healthy body weight, while the same proportion failed to recognise the importance of moderate alcohol consumption to reduce the risk of cancer.

Obesity is linked to an increased risk of bowel, kidney, oesophageal and stomach cancers, and also cancers of the womb and breast in post-menopausal women.

Dr Lesley Walker, director of cancer information at Cancer Research UK, said: "It's worrying to think that people are in denial about their weight.

"People who are carrying extra weight face significant health risks including cancer. Obesity is one of the biggest known preventable causes of cancer for those who don't smoke.

"These results show far too many of those at greatest risk are choosing to ignore their weight. They are unaware of their increased risk of cancer and unaware of many of the benefits of a healthy lifestyle."

Cancer Research UK has joined forces with charity Weight Concern to develop 10 top tips to help people maintain a healthy weight.

1 Eat at roughly the same times each day, whether this is two or five times a day.
2 Choose reduced fat versions of foods such as dairy products, spreads and salad dressings.
3 Walk 10,000 steps (equivalent to 60-90 minutes moderate activity) each day.
4 If you snack, choose a healthy option such as fresh fruit or low-calorie yoghurts.
5 Check the fat and sugar content on food labels when shopping and preparing food.
6 Do not eat huge portions and think twice before having second helpings.
7 Stand up for 10 minutes out of every hour.
8 Drink water or sugar-free squashes. Only drink one glass of unsweetened fruit juice - high in natural sugar - per day, and limit your alcohol consumption, as it is high in calories.
9 Eat slowly and at the table, rather than while on the go or watching TV.
10 Eat at least five portions of fruit and vegetables a day.