People should cut out alcohol and bacon entirely to slash their risk of cancer, says a global blueprint on preventing the disease.
Its authors say if people avoid sugary drinks and "stick to water", they can cut the risk by 40 per cent.
A 10-point plan issued by the World Cancer Research Fund follows a study of 51 million people - the most comprehensive analysis yet of cancer's causes. It links excess weight to at least 12 cancers - more than twice as many as its assessment a decade ago - and has specific advice on how to cut the risks.
Researchers say that evidence linking unhealthy lifestyles to cancer had grown since 2007, prompting them to issue the tough recommendations.
On current UK trends, obesity could overtake smoking as the leading cause of cancer within 20 years, they add.
Several studies have linked alcohol and processed meats to increased risks of cancer. Alcohol is most closely linked to breast cancer, and processed meats such as bacon increase the chance of bowel disease. The report says "alcohol is strongly linked to an increased risk of six cancers".
"No level of intake" of processed meats will reduce cancer risks, and experts recommend only a limited intake of red meat. The recommendations, launched at the European Congress on Obesity in Vienna, highlight the risks caused by obesity. The 10-point plan sets out a package of lifestyle changes to reduce the risk of cancer; such as being a healthy weight, physically active every day, and eating a varied diet, with plenty of fruit and vegetables.
Fund director Dr Giota Mitrou said the only drinks carrying no cancer risk were those containing neither sugar nor alcohol. "Sticking to water is best," she said.
The research warns that unhealthy lifestyles will fuel an increase in cancer cases globally by about 60 per cent in the next 40 years.
The review, led by Imperial College London, tracked all published studies involving 51 million people, 3.5 million of whom developed cancer.
"This is very robust evidence of what affects and doesn't affect cancer risk," Mitrou said. "With more countries adopting a westernised lifestyle, new cancer cases are predicted to increase to 24 million annually worldwide by 2035."
Mitrou said: "Our recommendations work as a blueprint to beat cancer, because they are based on evidence that has now proved consistent for decades."
The study says those in sedentary jobs should take "special care" to build exercise into everyday life.
Professor Linda Bauld, Cancer Research UK's prevention expert, backed the findings but said that people should not worry about the occasional glass of wine or bacon sandwich.
The "Mediterranean diet" hailed by health experts now barely exists in southern Europe, where the spread of junk food is fuelling a soaring obesity rate, researchers have found.
Cutting cancer risks: The 10 recommendations
Be a healthy weight. Keep your weight within the healthy range and avoid weight gain in adult life.
2. Be physically active. Be physically active as part of everyday life – walk more and sit less.
3. Eat a diet rich in wholegrains, vegetables, fruit and beans. Make wholegrains, vegetables, fruit, and pulses (legumes) such as beans and lentils a major part of your usual daily diet.
4. Limit consumption of 'fast foods' and other processed foods high in fat, starches or sugars. Limiting these foods helps control calorie intake and maintain a healthy weight.
5. Limit consumption of red and processed meat. Eat no more than moderate amounts of red meat, such as beef, pork and lamb. Eat little, if any, processed meat.
6. Limit consumption of sugar-sweetened drinks. Drink mostly water and unsweetened drinks.
7. Limit alcohol consumption. For cancer prevention, it's best not to drink alcohol.
8. Do not use supplements for cancer prevention. Aim to meet nutritional needs through diet alone.
9. For mothers: breastfeed your baby, if you can. Breastfeeding is good for both mother and baby.
10. After a cancer diagnosis: follow our recommendations, if you can. Check with your health professional what is right for you.