Get trim to lower risk of cancer

Excessive body weight has been found to be the No. 2 leading preventable cause of cancer

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The higher the risk.

The WHO grades excessive body weight thus: overweight (body mass index or BMI 25-<30); class 1 obesity (BMI 30-<35); class 2 obesity (BMI 35-<40); and class 3 obesity (BMI ≥40).

For uterine cancer, the risk increases 2.5-fold with class 1 obesity, 4.5-fold with class 2 and 7.1-fold with class 3. For breast cancer, the rise is smaller but still significant about 10 per cent for every five-unit increase in BMI.

The harm may be greater in Asians, who typically carry more body fat at the same BMI compared with Western populations. For this reason, the WHO Asia-Pacific guidelines classify overweight as a BMI of 23-<25, and obesity as BMI ≥25.

WHY DOES EXCESS WEIGHT CAUSE CANCER?

Several biological mechanisms explain the link.

In postmenopausal women, fat tissue becomes the main source of oestrogen, which can fuel breast cancer. Obesity forces the pancreas to produce more insulin, which also acts as a growth factor for cancer cells. Obesity increases pro-inflammatory molecules in the blood, driving genetic mutations and cancer formation.