“Together, (physical inactivity and unhealthy eating) are responsible for at least 400,000 deaths each year (CDC, 2004).”
Scientific evidence suggests that about one-third of the cancer deaths that occur in the US each year are due to poor nutrition and physical inactivity factors, including obesity. For the majority of Americans who do not use tobacco products, dietary choices and physical activity are the most important modifiable determinants of cancer risk.
Evidence also indicates that although inherited genes do influence cancer risk, heredity alone explains only a fraction of all cancers. The majority of the variation in cancer risk among populations and among individuals is due to factors that are not inherited. Behavioral factors such as cigarette smoking, certain dietary patterns, and physical inactivity can substantially increase one's risk of developing cancer. These factors modify the risk of cancer at all stages of its development. The introduction of a healthy diet and regular physical activity at any time, from childhood to old age, can promote health and impact cancer risk.
Physical inactivity and unhealthy diet contribute to the risk of other diseases as well. CDC (2004) states that physical inactivity and unhealthy eating contributes to obesity, cancer, cardiovascular disease, and diabetes. It continues to conclude that people who are overweight are at an increased risk for heart disease, high blood pressure, diabetes, arthritis-related disabilities, and some cancers.
Overweight and Obesity in the United States
The American Cancer Society (2003) researchers say current patterns of overweight and obesity in the U.S. could account for 14 percent of all cancer deaths in men and 20 percent of those in women.
A study by the American Cancer Society (2003) showed that stomach (in men), liver, pancreatic, prostate, non-Hodgkin lymphoma, multiple myeloma, cervical, and ovarian cancer is linked widely to unhealthy body weight. The same report also “substantiates previous studies linking overweight and obesity to cancers of the colon and rectum, breast (in postmenopausal women), uterus, kidney, esophagus, and gallbladder.”
The National Cancer Institute (2005) also suggests the same correlation; that as overweight and obesity trends increase and physical activity decreases the risk of developing many cancers rise. Obesity and being overweight are caused largely by diet and physical activity; therefore, making the promotion of healthy lifestyles important and vital in the prevention of cancer and other diseases.
Researchers predict that the epidemic growth in rates of obesity and overweight will cause cancer rates to soar 50 percent worldwide by 2020. Their conclusions are partly based on findings that simply being overweight and inactive produce hormonal and metabolic changes that create favorable conditions for cancer to begin.
Why? Cancer is a complex disease, and many factors probably explain the increased cancer risk excess weight causes. New findings, based on new technologies, suggest that fat cells constantly secrete a variety of hormones and other growth factors into the bloodstream.
In obese and overweight individuals, greater amounts of these hormones and growth factors are continually pumped into the bloodstream. Cells are urged to grow and divide at an accelerated rate. Thus, according to this theory, the random mutations that can lead to cancer are more likely.
In order to control weight and prevent obesity, physical activity is an important component that should be a part of one’s daily lifestyle. “A comprehensive 2002 international review by the International Agency for Research on Cancer (IARC) summarized, for the first time, the compelling evidence that prevention of obesity reduces risk for many of the most common cancers such as colon, postmenopausal breast, uterine, and renal cell cancers (2002).”