If you must learn from harsh experience, make sure it's the harsh experience of others. Insofar as your health goes, you only get one shot at living a long and healthy life as best you can. Why cut yourself short in ways that are shown to reduce lifespan? From JAMA: "High grip strength and avoidance of overweight, hyperglycemia, hypertension, smoking, and excessive alcohol consumption were associated with both overall and exceptional survival. In addition, high education and avoidance of hypertriglyceridemia were associated with exceptional survival, and lack of a marital partner was associated with mortality before age 85 years. ... probability of survival to oldest age is as high as 69% with no risk factors and as low as 22% with 6 or more risk factors. The probability of exceptional survival to age 85 years was 55% with no risk factors but decreased to 9% with 6 or more risk factors. ... avoidance of certain risk factors in midlife is associated with the probability of a long and healthy life among men."

Link: http://jama.ama-assn.org/cgi/content/abstract/296/19/2343