What does that mean? It means something very basic, and very interesting to me. It means that if you're sick, and your doctor discusses diet, exercise, and some supplements, either the doctor, or modern medicine does not understand what made you sick yet.
The best illustration of this? Well, when I was younger, I used to know people who had ulcers in the duodenum. They drank large amounts of milk, were told to stay away from acidic foods, were advised on how to stay away from stressful situations, they consumed a lot of tranquilizers, and were big fans of the over-the-counter stomach remedy Pepto-Bismol. The result? They still had the ulcers, but were "living with it" -- the ulcer was better that way than if they didn't do that. People published papers on the effects of dysfunctional family patterns on ulcer creations, and speculation was rife about such general causes.
That was a "lifestyle" management technique. Like "public health", lifestyle management is a powerful tool for coping with disease agents and reducing either their opportunity for infection or the severity of their infection. In 1982, the agent that caused the ulcer was found
, "helicobacter pylori", a bacterium that was specifically adapted to life in the stomach. If you follow the link, you'll get a really exciting story about its discovery and the adaptation of the medical profession to science. But the story has another meaning, as well: that if physicians don't know the cause of a disease, they will generally ASSUME it is a matter of lifestyle, attitude, and diet and go about trying to change that for you, and that assumption will work.
Why does it work? Well, because a healthy lifestyle which reduces opportunity for infection and/or severity of infections usually improves your general health, and allows your body to fight fewer things at once. You're improving, so you attribute it to the physician's advice, and are willing to pay the bill. But there's a limit on how far public health measures and a healthy lifestyle can take you, and that limit is different for each infectious agent. What becomes more interesting is when the medical profession gets sufficiently interested in removing the cause, and cooperates with research schools and pharmaceutical companies in getting the cure out there. Then actual knowledge slowly replaces lifestyle management, and a prescription is written that will clear it up within a reasonable period of time. Not all diseases have such useful causes: some, like high blood pressure and high cholesterol, are merely symptom management in an effort to improve things. But we need to look for the bullets.