"The public have been led to believe that everything causes cancer," says Cancer Council Australia CEO, Professor Sanchia Aranda, "but one-third of cancers are preventable by lifestyle factors."

A new study shows this figure may be a conservative estimate and as much as 40 per cent of cancer diagnoses and half of all cancer related deaths can be prevented through changes to lifestyle.

These changes involve: not smoking; no or moderate drinking of alcohol (one drink a day for women or less; two drinks a day for men or less); maintaining a healthy body weight (a BMI of at least 18.5 but lower than 27.5) and moderate aerobic exercise for 30 minutes, five days a week, or high intensity exercise for 15 minutes, five days a week.

These four factors were based on the health outcomes of more than 135,000 men and women, aged between 30 and 75.

Conversely, the study's authors from Harvard, noted: "Smoking contributed to 48.5 per cent of deaths from the 12 smoking-related cancers in the United States. Heavy alcohol consumption has been causally related to increased risk of cancers in several sites, including colourectum, breast, oral cavity, pharynx, larynx, esophagus and liver; and possibly to a higher risk of cancers of the lung, pancreas, stomach and gallbladder.

"Obesity increases risk of cancers in the esophagus, colourectum, pancreas, breast (after menopause), endometrium, kidney and liver; and probably increases risk of cancers in the ovaries, prostate (advanced only) and gallbladder. In contrast, physical activity has been linked to lower risk of cancers in the colourectum, breast and endometrium."

Their findings, "provide strong support for the argument that a large proportion of cancers are due to environmental factors and can be prevented by lifestyle modification".

In similar Australian research published last year, it was found that prevention is better than a cure. And while smoking cigarettes is the largest preventable cause of cancer, cleaning up your diet by simply adding more fresh fruit and vegetables can have a surprising impact, too.

"The association with smoking is well-known, but the study shows that 7000 new cancer cases a year are also attributable to low fruit and vegetable intake, low fibre intake and eating excess red meat," Aranda said in a statement at the time.

"Eating more fruit, vegetables and wholegrains is a positive step we can take to reduce our risk. These healthier choices also reduce obesity, the cause of 3900 cancer cases in its own right, and balance over-consumption of red and processed meat, which account for a further 2600 cases."

It is an empowering message, considering cancer is one of the leading causes of death in Australia.

We can do something about it, Aranda reiterates, noting that only about 10 per cent of all cancer diagnoses are genetic in a "truly inherent" sense.

"All cancer is caused by genetic mutation," she explains," but not all cancer is inherited.

"You can do something other than choosing your parents carefully."

The World Health Organisation's World No Tobacco Day is on 31 May 2016