Researchers at the American Cancer Society spent 16 years evaluating 900,000 people who were cancer-free when the study began in 1982. They found that excess fat may account for 14 percent of all cancer deaths in men and 20 percent of those in women. They conclude that losing weight could prevent more than 90,000 deaths from cancer each year. That’s one of every six cancer deaths in the United States.
I think the researchers should have concluded that lack of muscle, rather than just having too much fat, causes cancer. Your body produces millions of cancer cells every day that you are alive. However, your immunity should be strong enough to search out every cancer cell and kill them before they can start growing and multiplying in your body. As you age, you lose your ability to kill cancer cells and germs, because of lack of muscle.
When a germ gets into your body, you must make cells and proteins called antibodies to kill these germs. However, antibodies and cells are made from protein and the only place that you can store extra protein is in muscles. When you have large muscles, you have a ready source of protein from muscles to make antibodies and cells. When you have small muscles, you have a very limited source of amino acids to make protein, and your immunity is often inadequate to kill germs.
In the same way, you need antibodies to control cancer cells, so with loss of protein stores in your muscles comes loss of antibodies and increased susceptibility to suffer cancer.
If you are overweight, this study should scare you into exercising more and eating less. This is the largest study ever on the association between obesity and cancer, and it is the most statistically significant. The study has more than 10 times greater statistical significance than the largest previous research on the topic. It agrees with most previous studies that obesity is associated with increased risk for cancers of the breast, uterus, colon, rectum, kidney, esophagus, and gall bladder, and adds new associations between obesity and cancers of the cervix, ovaries, multiple myeloma, non-Hodgkins lymphoma, pancreas, liver, and in men, the stomach and prostate.