Chapter 32 in "The Code of Jewish Law" ("קצור שלחן ערוך") formulates Torah's directives regarding illness. It pinpoints the main cause for disease:
"Most illnesses visited upon man is for no reason other than from bad foods; Or, because one fills his gut beyond moderation even with good foods." (In Halachah 3)
Note this assertion's incisive, unequivocal and emphatic tenor -
"is for no reason other than"!
Similarly, Maimonides states categorically, "Most illnesses originate from what man ingests." (Mada 4:15).
(Maimonides was a doctor of sultans and princes. Even gentiles know of him; In Archives of Internal Medicine (Sep. 1999), it says, "Fittingly, the great physician and father of modern medicine Sir William Osler wrote that Maimonides was 'not only the Physician of Princes but also the Prince of Physicians.'")
Although the above law does not explain the word "most", we can reasonably assume at least 95% of illnesses have as their primary cause for culpability the above canon, otherwise the term would have been qualified.
"Ingestion" of course includes prescribed drugs, drinking fluoridated water, skin absorption of cosmetics, or of chlorine during swimming, inhaling deodorant spray or engine exhaust, etc., or taking into your body anything unnatural. Although environmental toxins can debilitate under high exposure, most exposure remains less than traumatic, although it certainly augments toxicity. This leaves improper food intake as the main cause of ill health.
According to Torah, then, the single most important cause of illness is improper intake of food. Either what is ingested is bad food ("toxic"), or, what's worse, believe it or not, eating good food beyond moderation. However, because our present culture is so far removed from the soil and fresh organic produce, the most common cause for illness has probably become - eating bad food beyond moderation.
This means people knowingly or, more likely, unknowingly, have themselves to blame for diseases they acquire! Similarly, knowingly or not knowingly, grown-ups are to blame for a child's onset of disease.
One might argue, how can that be; We hear about diseases of the liver, of the eyes, of the nerves, of blood sugar, blood pressure, the digestive tract, the joints, migraines, asthma, etc., so how can the simple, unitary act of food ingestion give rise to such a wide variety of sicknesses? This question, however, does not negate the truth of the aforementioned singular, main cause of illness. It is a good question and there is a good answer, but the question does not change the fact, which lays the blame for disease squarely on the individual himself - for eating improperly.
(But to answer the question briefly: The body's "weakest link" in the body's myriad networks of physiological functionalities breaks first.)
In Western culture, when a person becomes sick, his first thought usually is - "Which doctor or hospital do I go to?" Given that contemporary society regards medicine diametrically opposed to the Torah view, one where pill-taking is the norm rather than an exception, it's a shame. Only in case of emergency is that attitude understandable. But for an illness that crept up, or for one that's long chronic, the very best way to think should be - not "What doctor do I go to?", but rather - "How do I change my diet?". Such thinking, and subsequent corrective dietary action, are what conform to Torah's prescription for how to deal with at least 95% of illnesses.
You would think doctors themselves know the main cause of disease. Unfortunately most do not. For the last century or so, becoming a doctor meant following educational guidelines fixed by the pharmaceutical industry. Since then, this industry aggressively affiliated itself with many more industries that fell in line with it, or were bought out. Today, therefore, everything from medical education's curriculum, admission requirements, provision of licenses, the practicing slots available, administration of graduate tests, medical publishing, insurance claims, laws against alternative persuasions, pesticide regulation, artificial fertilization, hormonal supplements, sale of seeds and their genetic modification, cancer charities, etc. brainwash and enforce today's medical perspective and "knowledge". Which is why today's medical approach evolved into attacking symptoms, rather than the root cause - in order to push patentable drugs and advance invasive treatment. For example, a woman would be denied insurance for osteoporosis, unless and only if she got it from radiation treatments!
In contrast, that the body can take care of itself given an adequate supply of nutrients, while eliminating toxicity, makes no sense to today's medical practitioners. There's no money to be made going this natural way, so they just buried the evidence. What's worse, they also try to bury the practitioners who dare cure with alternative methods or with unpatentable herbs or diets.
There seems no way out of this anti-Torah attitude because "Big-Pharma" controls even governmental regulation of the medical establishment; Bribed overseers of medical practice sit in key governmental seats. The medical mafia is now huge, well-entrenched and outright ruthless. Any deviation from their declared policies invites harsh retribution.
Remember back to the time you last visited a doctor's office. Did he ever ask you what foods you eat? (At least some do ask about exercise, another important Maimonidic principle of health). In fact, when the doctor prescribes a pill, he knows full well you'll be eating the same things you've been eating up until now. In his mind, he makes no connection between food intake and disease. Walking out of a doctor's office without a prescription in hand is today practically unheard of. Which means, in effect, the doctor expects you to continue with the diet you've had until now, making no change to it, when, we know from Torah, that's the very reason you had to came to him in the first place!
Doctors know very little about nutrition and diet; They never learned such material in medical school. They were taught to follow blindly. For example, that fluoride in the water is "good for the teeth", that vaccinations help boost the response against future microbial attacks, or that pills of such and such help against so and so, they learn to accept with no good science to back these claims. These are educational slogans in their textbooks, which they later go on to "practice", blindly.
Even shopping for good organic food has become an enormous problem. We shop at huge supermarkets that contain practically all the food we eat. Since over 90% of the supermarket's foods are canned, jarred, frozen, pickled, colored, preserved, flavored, heated, processed, cleansed, filled with additives, etc., good foods are hard to come by. That's only part of the problem. The other part is its agriculture. Most fruits and vegetables today lack vital and adequate mineral content due to from chemical or artificial fertilization. This - besides the pesticides and other poisons they contain. Meats contain hormones and preservatives too.
Don't overestimate medical professionalism. They mocked Dr. Semmelweis (until he became insane) when he urged them to wash hands between patients. Until today they mock, legislate to death, or actually poison practitioners who hold firm in fighting disease in an "unorthodox" manner. This list of abused practitioners is very long indeed and even contains Nobel Prize laureates and prominent caregivers.
The public, in turn, gets its daily propaganda blared at them constantly by advertisements from Big-Pharma. It is almost impossible to avoid their barrage of disinformation, on radio, TV, print media, billboards, etc. Society is being brain-washed by this propaganda. And, if you hadn't yet noticed, they've gone after "diagnosing" and "treating" many of our youngsters too, effectively hooking these children on drugs for their lifetimes. And once they are labeled as "psychotic" they are forever at the mercy of abusive "doctor psychiatrists" (if ever there was quackery!).
The cruelty of medicine today is easily palpable. If a person comes down with cancer, the medical policy is to FRIGHTEN the victim into immediate action, because time, they say, is of the essence. The real reason for the medical push for early "treatment" is because the sooner the patient can be labelled and started on "treatment", the better his chances of lasting 5 years in life. Seeing it needs to come up with better statistics, the better to hide their failure in fighting this disease, modern medicine has managed to legislate into definition a new value for "cure"; If a patient lasts 5 years, he can be considered to have been "cured". They have twisted minds to accept their "progress" against this disease, when, in fact, they have failed. Taking NO cancer treatment in 98% of cases yields better results than taking them.
The only 3 legal ways to treat cancer in America today, chemotherapy (poisoning), radiotherapy (burning) and surgery (cutting). They've been at it now, with these often invasive, if not lethal or disfiguring, "treatments" nearly 100 years. Doing it otherwise, they keep saying, is "quackery".
Another reason to frighten the patient into quick action is to prevent the patient from seeking alternative forms of therapy. Their urging for quick action is certainly not for the sake of a better chance to cure the patient because under standard treatment (the 3 aforementioned) there is NO advantage to achieve a CURE! Most of the time, if the chemo- or radio-"therapy" has not killed the patient, the side effects these have often do.
Anyhow, with health education bereft of nutritional thinking, the public is generally left to know no better. The public does not realize that the body has enormous resourcefulness given a correct diet and detoxification. Just as sure as a skin bruise, or broken bone, can heal (with correct management), so too can cancer or most any other chronic degenerative disease. There are many great people who came up with brilliant strategies and simple means to CURE degenerative diseases who have been wiped clean from historical journals, let alone practice, because of the medical mafia.
Okay - let's get back to why disease happens in the first place. It's because of the food we eat. And so, if the person becomes sick, the first thing to rule out is a faulty diet. After all, as good doctors know, what is common is common. People should NOT be looking for OTHER reasons why they are sick. As good medicine reminds practitioners, when you hear a clatter of hooves, don't think "zebras", think "horses" - because that's what's common! Therefore, the very first thing to investigate as the cause of disease is - the food you put into your mouth!
Maimonides tells how to regain health; When to eat, how to eat, what to eat, what else to do and what not to do, to get well. Not once is mention made of ingesting some sort of elixirs certainly not pills.
But brainwashing has powerful influence. Many Jews (and Gentiles) today could read the above number-one-reason-for-illness even 100 times, and still will not "get it". This is my small way to try and make a dent in that naive trust.