They found that processed meats and alcohol increase a person's risk of cancer, even in small amounts. High weight gain (defined as an increase of 10kg or more in 6 years) was associated with a 36% increased risk of postmenopausal breast cancer, a 40% increased risk of endometrial cancer.
This is despite the fact that no link was found between BMI and the likelihood of developing pancreatic cancer.
These cancers include cancer of the liver, ovary, advanced prostate, stomach (cardia), mouth and throat, bowel, breast (post-menopause), gallbladder, kidney, oesophagus, pancreas and womb (endometrium).
The experts advice that only moderate amounts of red meat should be consumed, and alcohol consumption should be limited.
The largest increase was seen in endometrial cancer, with obese women more than twice as likely to develop it, compared with women of normal weight. "While following each individual recommendation is expected to offer cancer protection benefit, the most benefit is to be gained by treating them as an integrated pattern of behaviours relating to diet and physical activity, and other factors, that can be considered as a single overarching "package" or way of life", the report reads. "But for cancer prevention, we are confident that for most people eating the right food and drink is more likely to protect against cancer than taking dietary supplements".
"We are making for the first time separate recommendations on sugar-sweetened drinks and the recommendation is to drink water and unsweetened drinks and to limit consumption of fast foods and other processed foods", said WCRF director of research Dr. Giota Mitrou, as cited by the Mirror. However, a healthy diet rich in wholegrains, fruit, vegetables and pulses, and low in red and processed meat, reduces the risk.
The authors of the report said that approximately 40 percent of cancers are actually preventable, but despite that the number of new cases is expected to rise by 58 percent to 24 million globally by 2035.
People should reduce their consumption of fast food and those high in fat, starches and sugars to help control calorie intake, it states.
To assess the impact of this intervention on cancer outcomes, investigators merged the data from the Oslo study with data from the Cancer Registry of Norway and the Norwegian Cause of Death Registry from 1972-1973 to the end of 2015. "Our cancer prevention recommendations work together as a blueprint to beat cancer that people can trust, because they are based on evidence that has now proved consistent for decades". She also called on the government to act to curb junk food marketing.