This Is How Excess Weight Can Fuel the Growth of Cancer Cells

[Guest Nicole]

It’s pretty obvious that carrying around extra weight can make you feel sluggish, affect your self-esteem and put you at increased risk for heart disease and diabetes. But increasingly, researchers are also making connections between obesity and cancer—several different types of cancer, in fact.

Cancer is caused by mutations within cells, which cause those cells to grow and multiply at unnatural rates. Many cases of cancer occur because of genetic traits, or purely because of chance. But for others, obesity can be a big contributing factor.

“We know that a good third of cancers are associated with our lifestyle behaviors, such as what we eat, how much we exercise, and collectively, our weight,” says Melinda Irwin, director of Cancer Prevention and Control at Yale University. “And obesity is now the leading modifiable risk factor, even ahead of tobacco use, that’s associated with cancer risk and mortality.”

How does obesity encourage cancer growth?

High-levels of long-term inflammation—the immune system’s response to injury, illness, or other disturbances in the body—has been shown to fuel the growth of cancer cells. “And we know that obesity is basically a chronic inflammatory state,” says Irwin.

Not only can obesity itself trigger inflammation; so can some of the the eating behaviors that lead to weight gain in the first place—like high-sugar and high-fat diets. Having too much fat around the belly, regardless of body mass index, increases inflammation in the body, as well.

Some cancers are also linked to sex hormones like estrogen. Women’s bodies produces estrogen in their fat cells, especially after menopause. “The higher levels of body fat you have, the higher levels of estrogen,” says Irwin.

Then there’s the way that obesity contributes to insulin resistance—a condition in which the body loses its sensitivity to the hormone and can’t respond normally. This can lead to excess levels of insulin and insulin-related growth hormones in the body, which has been linked to cell proliferation and several types of cancer.

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