Whole Food IS Medicine
Wow, there is no short answer. For eons mankind has eaten raw, natural foods. Whole Foods, not processed, no additives, no chemicals, not genetically modified or otherwise messed with. Only in the last 100 years or so have we started to mess with food. Pesticides, especially after WW2, chemical unnatural fertilizers (byproducts of the gasoline refining industry) and now genetically modified 'foods' or organisms (GMO). In addition the meat you may eat (we are Plant Based, so do NOT consume meat, dairy, eggs or fish) is not farm raised (nor is most of the fish) as it was 100 years ago.
Mankind cages up animals and basically force feeds them 'stuff' they would never naturally eat. Grains and fodder in high concentrations that would never be available in nature. These high concentrations of protein and fats cause excessive growth. The growth hormones pumped into the animals make them grow bigger/fatter quicker (faster to market). Because of the overcrowding conditions (meat, poultry, fish farming and dairy industry) the animals develop all sorts of disease, caused by close quarters and often unsanitary conditions, this disease would run rampant if not for the buckets of antibiotics pumped into the animals just to keep them alive. In addition most of the grains (corn, soybean, sorghum etc.) are genetically modified so you get a double bank of dangerous chemical/genes that passes to those who eat these animals and their byproducts (milk, gelatin etc.).
Hungry yet? <smile>! None of this comes close to the natural diet that humankind has eaten for eons.
Now we come to the 'processed foods'. The stuff you get in drive-though, ready to eat meals, most any 'packaged food'. Just read the label! Dyes, additives (who knows what most of that stuff is?) and high sugar (high fructose corn syrup etc.), high fats and protein concentrates. All this is dense food that is LOW in fiber but tastes good because of the sugar and additives (MSG...). In addition the raw materials are usually processed before being used to create the processed/packaged food. The white flour and such is stripped of it's fiber and nutrition. In many cases you might be better off from a nutrition standpoint eating the wrapper than the product! <grin>!
Like I said, no short answer. This is just the tip of the iceberg before you sink; contract diabetes 2, cancer, heart disease or other lifestyle diseases that rarely existed 100 years ago! We are even seeing many of these illnesses in kids!
Before traditional 'modern medicine' there were few drugs or doctors for that matter. Man lived in groups of either agrarian or hunter-gathering communities. Eventually these combined to our current 'civilization'. Medicine men/women and others (soothsayers, philosophers, alchemists, etc.) treated sick people as best they could with herbs and combinations of natural ingredients that often still are the basis of modern medications (aspirin is one great example). Most of today's lifestyle diseases just didn't exist or occur with any frequency. True, due to the dangerous existence or early city pollutions (Dark Ages) most people didn't live long enough to get diseases we now see in geriatric patients. But many of these lifestyle diseases are now being seen in kids before puberty. Diabetes 2, obesity, cancers, even heart disease and coronary artery disease!
WHY? Because you ARE what you EAT! That is your short answer to your question. Food provides the basic nutrition to maintain a healthy body. That includes your natural healing system and immune systems. These are highly complex mechanisms that are barely understood by 'modern medicine'. 99% of medal practitioners today have little or no training in basic nutrition (ask your own doctor how many hours of formal education he/she received in nutritional science in Medical School!).
It is the Healing Systems and Immune Systems that keep you alive! They fight disease, heal cuts, bruises, broken bones (after correct setting) and when/if surgery is called for, help you heal. You cells in your body are constantly being replaced; ALL of them. Diseases, bacteria, germs and viruses and yes cancer, is constantly present in your body. Everyone's bodies. They don't succeed or take over because your body's defenses fights them off. Most of the time very successfully.
Just like any other engine, your body needs fuel. The better the fuel, the better the function and smoothly running engine. Just like a car, the better the gas the better the performance. Change the oil as everyone knows that the oil is the cleansing and lubrication mechanism of the machines. The SAME goes for the body. Provide the proper nutrients and you run smoothly. The fiber in your diet, does the same as the oil in a car, it helps clean the gunk out and flushes it. The oil/gas filter is the same as your kidneys and liver. All these complex bodily systems make a car engine look like a tinker toy. The body is SO vastly complex, 'modern medicine' for the most part has NO CLUE how it really works. Sure they can tinker, take stuff out and patch it up and hope it runs, but if you have a Rolls Royce or a Bentley automobile, do you take it to a local handyman for major repairs? Not so much!
Food is the fuel for the body. Give it proper fuel and you run well. Feed it crap and it knocks and konks out, often leaving you stranded. Your body is much the same, only vastly more complex!
So, really food is not really 'medicine' in the traditional use of the term. It is the PREVENTATIVE that allows you to fire on all cylinders without additives (drugs). If you provide your body with the proper nutrients, you just don't need 'medicine' in the common usage of the term. Only when you mechanically break a part (broken arm, serious injury, etc.) do you need repairs, then thank goodness for your Emergency Room doctors! THEY are wonderful at 'fixing' you up after an accident.
If you take care of yourself, manage to avoid injury (accidents), your body should last 120 years, maybe more. There are plenty of examples of people in their 90's and more living vibrant, active and healthy lives. They eat well, exercise and enjoy life. Unfortunately, there are more and more people who eat poorly (fast food, processed food, GMO 'food', etc.) who's health is failing and they are dying or living sedentary miserable lives.
The WONDERFUL news is, you can CHANGE things for the better. It is NEVER too late! Change the fuel, clean out the engine and the body will repair itself! That is the miracle of the human body. It has the capability to repair itself, heal itself, IFF given the proper fuel/nutrients.