A recent article published in Science looked at the effect of gut microbiome and prostate cancer. Obesity alters the gut flora. It has been known for some time that obese men are more prone to prostate cancer. Now, it seems there is a cause and effect.
A current treatment for prostate cancer is castration (to remove the driving force of testosterone) either chemical via anti-androgens or surgical. This almost uniformly leads to a very good clinical response. But in some patients this response is short lived because their gut flora alters to bacteria that can produce androgens (testosterone). This switch phenomenon is more likely to occur with obesity. Currently research is ongoing to find an antibiotic therapy to eliminate these mischievous microbes or a form of probiotic to displace them.
While that research is being completed another approach is via self-reliance. It is known that even modest weight reduction (10 to 15 pounds) has a favorable impact on the gut microbiome. In addition, adding a probiotic and selecting foods to support the probiotic (pre-biotics) can reduce the bad gut flora.