Why is keeping a normal body weight so important to cancer prevention?
We know that being overweight or obese is strongly linked to an increased risk of several common cancers – like cancers of the colon, breast, kidneys, esophagus, endometrium, and pancreas to name a few. We think there could be several reasons why.
Excess body fat, especially around the waist, is linked with insulin resistance and high insulin levels. Although people associate insulin with blood sugar and diabetes, researchers think that high levels of insulin may promote the growth of cancer cells. Excess fat also seems to trigger inflammation throughout the body, which seems to encourage cancer growth.
Excess body fat can pose a specific risk to older women. After menopause, excess weight is associated with higher levels of estrogen. That can promote the development and growth of estrogen-sensitive cancers of the breast and endometrium.
How does physical activity affect a person’s cancer risk?
We now think that physical activity has a vital role in lowering cancer risk. It can directly reduce insulin resistance, inflammation, and the levels of reproductive hormones. Indirectly, it can help achieve and maintain weight loss, as well as prevent the weight gain that many adults experience as they get older.
The current recommendations from the American Institute for Cancer Research are at least 30 minutes a day of moderate physical activity. And if you can, you should aim for 60 minutes a day – or 30 minutes of more vigorous activity. You’ll achieve even better cancer protection and weight control.
Does meat or any other type of food contribute to the risk of cancer?
There’s a pretty convincing link between red meats and colon cancer, and possibly other cancers as well. It’s not just the fat. Although choosing lean meat is good for nutrition, it’s not enough to reduce the cancer risk.
However, you don’t have to give it up completely. Eating up to 18 ounces of red meat a week seems to be safe. You just want to make meat an occasional food instead of one that you eat daily.
Eating processed meat -- which is salted, cured, smoked, or treated with preservatives -- seems to have an even greater risk of colon cancer. So you should try to limit that as much as you can.
You should also be careful of how much sodium you get – more than 2,400 milligrams a day seems to increase the risk of stomach cancer. Eating fewer processed foods can help with that. Alcohol also increases the risk of several cancers, so from a cancer perspective, the less you drink the better. Women should have no more than one drink a day and men no more than two.