Almost 12,000 men and women had their weight and waist measurements taken in 1993/4. Researchers then compared these statistics with weight and waist measurements in a similar sample taken from the Health Survey for England 10 years later.
People who are overweight or obese have an increased risk of cancer. Male obesity had risen from 13.4 per cent in 1993/4 to 22.7 per cent in 2003/4 and female obesity from 15.8 per cent to 22.4 per cent according to the study published online today in the
Men's waist circumference increased by 3.48 cm and women's increased by 4.35cm.
Researchers also found that the proportion of men and women under 45 who were morbidly obese (with a BMI of over 35) doubled over the 10 year period - as did the proportion of women with a BMI of more than 40.
Professor Jane Wardle, director of Cancer Research UK's health behaviour unit and study leader, said: "We found that weight gain in the population has been unequally distributed. Slimmer adults today are almost as slim as their counterparts 10 years ago but the heaviest people in the population are much heavier than they were 10 years ago.
"These inequalities are greatest among those under 45, suggesting that environmental changes are having a greater impact on young adults. Snacking habits, takeaway meals high in fat and sedentary lifestyles where many people spend both work and leisure time sitting in front of a computer are all likely to contribute to the results.
"It seems that some people are more susceptible to changes in the environment than others and the explanation for this may be partly genetic. It is important for psychologists, geneticists and biologists to work together to discover the reasons for this."
Dr Lesley Walker, director of cancer information at Cancer Research UK, said: "This research adds to the evidence that the UK is in the grip of an obesity epidemic. We know that high body weight increases the risk of a number of cancers and it is important we get this message out to as many people as possible.
"A healthy diet with plenty of fibre, fruit and vegetables as well as regular exercise can help people to lose weight and reduce their risk of cancer. Cancer Research UK, together with the charity Weight Concern, has devised Ten Top Tips to help people control their weight."
Research shows that 12,000 cases of cancer could be prevented each year in the UK if the Body Mass Index of every adult did not exceed 25 - which is categorised as being overweight. A BMI of over 30 is categorised as being obese.
Ten Top Tips
The tips are simple habits that everyone can permanently fit into their daily routines. Keeping up all ten tips in the long term will help you lose weight and keep it off.
1. Keep to your meal routine. Try to eat at roughly the same times each day, whether this is two or five times a day.
2. Go reduced fat. Choose reduced fat versions of foods such as dairy products, spreads and salad dressings where you can. Use them sparingly as some can still be high in fat.
3. Walk off the weight. Walk 10,000 steps (about 60-90 minutes of moderate activity) each day. You can use a pedometer to help count the steps. You can break up your walking over the day.
4. Pack a healthy snack. If you snack, choose a healthy option such as fresh fruit or low calorie yogurts instead of chocolate or crisps.
5. Look at the labels. Be careful about food claims. Check the fat and sugar content on food labels when shopping and preparing food.
6. Caution with your portions. Don't heap food on your plate (except vegetables). Think twice before having second helpings.
7. Up on your feet. Break up your sitting time. Stand up for ten minutes out of every hour.
8. Think about your drinks. Choose water or sugar-free squashes. Unsweetened fruit juice contains natural sugar so limit it to 1 glass per day (200ml / 1/3 pint). Alcohol is high in calories; try to limit the amount you drink.
9. Focus on your food. Slow down. Don't eat on the go or while watching TV. Eat at a table if possible.
10. Don't forget your 5 a day. Eat at least five portions of fruit and vegetables a day (400g in total).