The second biggest preventable cause of cancer: being overweight.
While most people are aware of the biggest cause of cancer – smoking – many are unaware of the second biggest: being overweight or obese. In fact, three in four people aren’t aware that obesity causes cancer. The evidence linking bodyweight and cancer has been building for decades, with new evidence still emerging.
It’s important to remember that although cancer risk is increased in people who are overweight, this doesn’t mean they’ll definitely develop cancer. Cancer risk is affected by many different factors – including whether you smoke, how much alcohol you drink, and your genes.
How does weight affect cancer risk?
Researchers are still trying to figure out exactly how carrying extra weight causes cells to become cancerous, but it’s likely down to the chemical signals that are released from the extra body fat.
Some body fat is essential. It’s our back-up energy store and it makes chemical signals that help keep our bodies in check. But when we have too much body fat, it can have harmful effects.
We’ve blogged about the three main theories in detail before. In a nutshell, the extra fat we carry releases hormones and other growth-promoting signals around our bodies. It also causes inflammation. And each of these has an effect on how often our cells divide. And it’s these changes in cell division that are most likely behind the increased risk of cancer.