In my early twenties, i was overweight, drinking/ smoking everyday. now i'm fit/eat healthy. but i'm petrified of cancer. are my efforts now pointless?

Nonsense!: You deserve congratulations, not punishing regret. You can't change the past and since you straightened out your bad lifestyle choices early in life, I would like to think it will pay off well for you. Do this: keep your healthy lifestyle, get the proper screenings for your age and risk, and move ahead. No looking back, OK? Be proud of what you've done.

No: Being in good health with proper wt. and exercising is important for cardiovascular health. While it was felt that certain fats would predispose to cancer, most if not all changes in diet will not affect susceptibility. Other for congenital malignancies related to breast or colon, the majority are induced by a series of events many of which are associated with viral or carcinogen exposure.

Your efforts/ useful: Healthy life style at any age is very helpful to keep yourself in good health. So your efforts to eat healthjy and be fit will pay dividends. Cancer can occur in anyone, yet it is uncommon. So most people can abuse their body and often get away... it is just that odds of serious illness diminish with good life style and odds go up with poor lifestyle. That is why 80% of the smokers don't get Cance