In the United States, smoking is undeniably the #1 preventable cause of cancer but still kills over 500,000 people a year. However, researchers have found that obesity has been ready to take the top spot as the #1 preventable cause of cancer, because obese people in Americans have a waistline that continues to expand, making them vulnerable to cancer than smoking.
Dr. Otis Brawley, an oncologist at Johns Hopkins and former chief medical officer of the American Cancer Society, said, “The switch could occur in five or 10 years. The rise in obesity rates could threaten the steady decline in cancer death rates since the early 1990s.”
Unfortunately, about half of Americans are not aware of the link between obesity and cancer. Researchers have been struggling to answer basic questions how obesity increases the risk of cancer and how losing weight prevents cancer.
In recent years, obesity has been associated with an increased risk of getting roughly 13 types of cancer, which include cancers of stomach, pancreas, colon, liver, and breast.
Researchers say that too much body weight is linked to nearly 8 percent of all cancers in the United States and 7 percent of deaths from cancer.
When compared with people of normal body mass index (BMI), obese patients are much more likely to have a cancer recurrence and have a lower rate of survival.
In the United States, young people are developing obesity-related cancers, such as colon cancer, at a very early age than previous generations.
Although the exact link between obesity and cancer is not clear, researchers have been focusing on the so-called “visceral fat” that surrounds the internal organs.
Visceral fat is a “metabolically active organ,” which can produce hormones such as estrogen, increasing the risk of breast and some other types of cancers, according to the American Institute for Cancer Research that focuses on diet, nutrition, and cancer.
The fat is also known to secrete proteins that increase insulin levels, spurring cell growth and increasing the risk of cancer. Visceral fat is also responsible for causing chronic inflammation, another risk factor of cancer.
According to a 2015 article in JAMA Internal Medicine, nearly 7 in 10 Americans are obese or overweight. People are considered obese if they have a BMI of 30 or more and overweight if they have a BMI of 25 to 29.
In women, obesity is strongly associated with endometrial cancer. It has been found that obese women are two to four times more likely to develop endometrial cancer than women with normal BMI, and the risk increase with weight gain.
According to NIH, obese people are about two times more likely to develop liver and kidney cancer and about 1.5 times more likely to develop pancreatic cancer than people of normal weight are.
Furthermore, too much abdominal fat is strongly associated with an increased risk of colon and some other cancers, irrespective of body weight, according to the cancer society.
So, for anyone who wants to reduce their cancer risk, they should avoid gaining weight in the first place, experts advise. Dr. Brawley of Johns Hopkins said, “The goal should be maintaining ‘energy balance’ — consuming no more calories than are burned off through exercise and other activity.”
Dieticians say that the key is to cut down on portion sizes, avoid sugar, and aim for meals rich in vegetables, fruits, whole grains, beans, and light on animal protein. Experts have found that the Mediterranean diet has been linked to improved cancer outcomes and improve the survival rate. The diet emphasizes mainly on plant-based food, whole grains, and olive oil.
