Which lifestyle factors reduce your cancer risk the most?
Not smoking, a healthy weight, regular exercise and little or no alcohol have the strongest and best-supported protective effect. Combining all these factors lowers cancer risk the most, even when a hereditary predisposition is present.
Not smoking is the most powerful step you can take. Smoking is a proven cause of cancer, not only lung cancer but also colorectal cancer and other types. Quitting substantially lowers the risk, even if you have been smoking for many years.
Maintaining a healthy weight and exercising regularly share second place. Being overweight increases the risk of breast, colorectal and prostate cancer. Physical activity helps both directly, through a beneficial effect on your metabolism and immune system, and indirectly by helping you keep your weight in check. Both factors have been found consistently across large reviews.
Limiting or cutting out alcohol reduces the risk of colorectal cancer, breast cancer and possibly lung cancer. Even moderate alcohol consumption has been linked to an increased risk in several large reviews; there is no established 'safe' amount.
What you eat also makes a difference, although the effect is more modest. A dietary pattern high in whole grains, vegetables, fruit and legumes and low in processed meat offers protection particularly against colorectal cancer. Processed meat increases the risk; fresh produce and fibre lower it. Highly processed foods and sugary drinks count indirectly through overweight and inflammation.
For people with a genetically elevated cancer risk, something notable applies: in absolute terms, a healthy lifestyle delivers greater benefit for them than for people without such a hereditary predisposition. Lifestyle does not cancel out that predisposition, but it does noticeably temper the risk. Vitamin D and calcium have been linked to a lower risk of colorectal cancer, but the strength of evidence is limited and no firm dosage recommendations can be given.
Based on multiple large reviews and a large cohort study (UK Biobank, n=195,822). The claims about smoking, weight, physical activity and alcohol are well supported. Diet has strong support specifically for colorectal cancer. Vitamin D, calcium and tea are based on limited evidence. The coffee result (increased lung cancer risk) is likely distorted by smoking behaviour.
What can I do myself to lower my risk of cancer?
By not smoking, limiting alcohol, maintaining a healthy weight and exercising enough, you can demonstrably lower your risk of several common cancers, even if cancer runs in your family.
Does drinking less alcohol meaningfully reduce your cancer risk?
Drinking less alcohol meaningfully reduces your risk of several cancer types, although it takes years before the full effect becomes visible. Stopping sooner yields greater health gains.
Does exercise lower my risk of cancer?
Regular physical activity is associated with a clearly lower risk of several cancers in large population studies. Alongside that, aim to reduce the number of hours you spend sitting during the day, and use sun protection if you do a lot of outdoor sport.
Does eating less red meat lower your risk of cancer?
Eating less red and processed meat probably lowers your risk of colorectal cancer, and possibly of several other cancer types as well. This concerns risk reduction, not complete protection.
From how much alcohol do I actually face a higher risk of cancer?
Even with light drinking your risk of mouth, throat, oesophageal and breast cancer is already measurably higher. A safe lower limit does not exist.
Does being overweight increase my risk of cancer, and if so, which types?
Excess weight increases your risk of at least 13 types of cancer, including uterine, colorectal, breast and liver cancer. Losing weight reduces that risk, although it remains unclear whether all methods of weight loss are equally effective for immune defence against cancer.