Look, whether you like it or not, you can’t live forever. I bring this up because there is always a new book or new add purporting to have “the answer” to long life and good health, which never includes modern, evidence-based medicine. Still, perhaps some of these books contains good advice. Or not. Let me explain.
First let me disabuse some of you of the thought that doctors don’t “do” nutrition and life-style advice. In fact, we do. And as attractive as the idea seems, life-style modification will never be the answer to all of (or even most of) our medical problems. Leaving aside the fact that many people cannot make permanent and beneficial changes in their life-styles, there are many other reasons. Human health and disease is complex. Most diseases are multifactorial. For example, type II diabetes is caused by a combination of genetic factors and diet. Some patients can remain off medication using diet and exercise. Some cannot, as even with a good body mass index, good diet, and good exercise habits, their blood sugars are still out of control. Another example is hypertension. Dietary sodium reduction has been shown to reduce blood pressure, but many patients will not have significant enough improvements in blood pressure through diet and exercise alone.
Another reasons that lifestyle changes aren’t the whole answer is that sometimes drugs provide benefit that diet and exercise cannot. For example, beta blockers reduce blood pressure, but they also prevent sudden and premature death in certain groups of patients (i.e. those with significant heart failure), independent of the effect on blood pressure.
Finally, many purely genetic diseases are not amenable to lifestyle modification. No amount of diet and exercise will fix cystic fibrosis or congential adrenal hyperplasia.
Living healthy is important, but there is no miracle to maintaining health and treating disease. No one book is going to help you live forever. Lifestyle modification is not the answer to every medical question, no matter how much we all wish it were.