Obesity and Cancer: What You Need to Know
Obesity is now one of the leading causes of cancer. It also appears to play a role for survivors, including their risk of other chronic diseases.
There are several ways in which scientists are seeing that extra body fat may increase cancer risk. Fat tissue can cause chronic inflammation, which links to increased cancer risk. Being overweight and obese also increases blood levels of insulin and related hormones that can spur the growth of cancer cells.
As researchers continue to unravel how extra body fat spurs tumor growth, there are some things that are becoming clear.
1. Getting to and staying a healthy weight could prevent 320 cases of cancer each day
AICR estimates that carrying extra body fat will cause approximately 117,000 cases of cancer in the United States this year. The latest government statistics show that approximately two thirds of U.S. adults are overweight or obese; one third of children are overweight or obese.
Overweight and obesity are linked to increased risk of seven cancers: colorectal, post-menopausal breast, esophageal, endometrial, kidney, pancreatic and gallbladder.
2. There's a good chance your friends and family do not know obesity is a cause of cancer
A 2013 AICR survey found that more than half of Americans – 52 percent – are unaware that overweight and obesity link to higher cancer risk. That’s a drop in awareness from the 2009 survey, and represents the first time awareness of this major cancer risk has dropped since the survey began in 2001.
Cancer was also among the least known health problems related to overweight and obesity, according to a Associated Press-NORC Center for Public Affairs Research: 8 percent knew it affects risk of death; 21 percent knew it affects high blood pressure, and 14 percent knew it affects arthritis and joint problems.
3. Not all fat is the same
At one time, researchers thought fat was fat and it didn't do much. Today, scientists know that body fat is a metabolically active -- and essential -- tissue. There are also distinct types of fat, each with its own characteristics and functions.
For example, the fat located deep within our belly or abdomen is called visceral fat. Visceral fat is an independent risk factor for cancers of the breast and colorectum. It also may indicate higher risk of metabolic abnormalities that can play a role in type 2 diabetes and other chronic diseases.
4. Losing small amounts of weight may make a real difference
AICR's expert report and its continuous updates found that the more overweight people were, the higher the risk. That means for those who are overweight and obese, losing weight and keeping that weight off may lower risk.
Some biological indicators for higher cancer risk are similar to those of heart disease. Major new heart health guidelines published in November stated that when patients lose just 3 to 5% of their weight and keep it off they will achieve meaningful health benefits. Previously, the standard was a 5% weight loss.
BMI is a standard way to measure your body fat: here's our BMI calculator.
AICR's online weight loss program launches this month: Join the New American Plate Challenge (for free) and be part of the NAP community.