American Cancer Society researchers spent 16 years evaluating 900,000 people who did not have cancer 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 women. They conclude that losing weight could prevent more than 90,000 cancer deaths each year. That’s one in six cancer deaths in the United States.
I think the researchers should have concluded that lack of muscle, rather than having too much fat, causes cancer. Your body produces millions of cancer cells every day that you are alive. However, your immunity must be strong enough to seek out each cancer cell and kill it before it can begin to grow and multiply in your body. As you get older, you lose the ability to kill cancer cells and germs due to a lack of muscle.
When a germ enters your body, it must make cells and proteins called antibodies to kill these germs. However, antibodies and cells are made of protein, and the only place you can store extra protein is in your muscles. When you have big muscles, you have a ready source of muscle protein 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 the loss of protein stores in your muscles comes loss of antibodies and increased susceptibility to cancer.
If you’re overweight, this study should scare you into exercising more and eating less. This is the largest study ever conducted on the association between obesity and cancer, and it is the most statistically significant. The study is more than 10 times more statistically significant than the largest previous research on the subject. It agrees with most previous studies that obesity is associated with an increased risk of cancers of the breast, uterus, colon, rectum, kidney, esophagus, and gallbladder, and adds new associations between obesity and cervical cancers, ovaries, multiple myeloma, non-Hodgkin lymphoma, pancreas, liver, and, in men, stomach and prostate.