You must be from the school that believes that each "disease" has one unique "cause" and one unique drug to cure it.
I'm from a school that believes that all "disease" has a single cause "toxemia" although toxemia can be caused by a number of unhealthy practices. The cure is to stop the unhealthy practices, start the healthy practices and allow the body to detoxify itself and return to homeostasis.
Either you didn't mean to write that, or you have poor short-time memory

.
You believe that disease has a single cause with a single cure, unlike the people who believe disease has a single cause and a single cure?
You're overlooking the word "each."
Conventional medicine's paradigm is that
each disease has its own specific cause and a specific cure none of which includes your diet except possibly as aggravating circumstances. They go through elaborate diagnostics to establish what disease you have so that they can decide the appropriate treatment to prescribe. In practice, you wind up a with a cocktail of medicines for various symptoms and a number of those are to counteract the side effects of the main drugs.
In Natural Hygiene, there's no need to wait for a diagnosis because if you're unwell, you start a complete rest including a water fast and when you've recovered you return to (or transition to) a healthy lifestyle in accordance with the laws of Nature.
(Just in case this seems at odds with my previous answers,) living a healthy lifestyle as such supports ultimate health but unfortunately, each person's ultimate health potential can vary based on how good a start they got in life as well as any indiscretions before adopting a healthy lifestyle. For example, if you shot your liver full of holes with alcohol before cleaning up your act, you will have to survive on whatever liver functionality remains when the body has repaired what it can. That can significantly affect your quality of life.
If you were born without hips, you're unlikely to spontaneously generate them regardless of how long you fast. And eventually, you will pass on to the great internet forum in the sky and the quality of your lifestyle will no doubt influence the quality of your death. It's your choice.
For those confused about healthy lifestyles, please note that vegan doesn't mean raw fruit and veg. Vegan means abstention from eating or using animal products although many vegans follow a raw food diet. Other vegans eat unhealthy grains and legumes, processed oils and cooked foods of various types complete with added salt. High fat, high-protein, high-sodium, high-sugar and all cooked to boot. Just what the doctor ordered.
I'm bowing out now so for answers to your burning questions, please just [insert favorite internet search engine here] Natural Hygiene and start reading. Good luck.