So if these 40% of cancers were eliminated, what's the chances that the survivors would have ended up with one of the remaining 60%?
You have to die of something. What's important is years of high-quality life, rather than merely avoiding death from any specific ailment. And of course, quality is ultimately a subjective measure. All the behaviours that you must conform to, to avoid these specific deaths, may themselves detract from your quality of life.
That seems like it depends heavily on what you consider "quality of life". In any case, it needs a lot more data to determine (alcohol in particular seems to have both complex health effects, and complex, culture-dependent sociological/psychological effects).
I could just as easily assert the opposite: eating fewer steaks and drinking less reduces your quality of life, right now.*
* But may increase it in the future, depending on various factors.
Almost all food advertised or described as "healthy", I've found to be neutral at best, to actively unpleasant. High fibre, lots of vegetables, fruit, etc.; I actively dislike almost all of it. My favourite foods are lamb, butter, cheese and freshly baked goods, to the point that my morning ritual, before breakfast, involves a (scooter) trip to a bakery.
Similarly, I've never enjoyed exercise. I used to cycle to and from school every day, about 6 miles, fairly high intensity (due to my laziness, I'd start late). My aerobic capacity was certainly higher then; I could run for perhaps 30 minutes, where I'd hazard a guess that I'd be out of breath after 10 minutes now. I'm not overweight, have no difficulty walking, jumping, running, climbing hills etc. when I get the occasion to on vacation and such. But the thought of actively exercising fills me with weariness. Not enjoyable.
What I'm getting at is that I have a lifestyle that I massively enjoy, and it took a lot of experimentation and experience to discover the things I like best. Whether it is specifically healthy or not is secondary, by a long way, to how enjoyable it is.
Some of that falls into my "healthy" category, some not. As to palatability, much depends on preparation. I like fruit and vegetables, but you'll find that some herbs and spices, heating (especially roasting) and a bit of oil (olive oil, butter) really bring out flavors. Mostly for me it's veggies, a few whole grains, some fruit, ample protein (from clean sources) and healthy fats (good mix of saturated/unsaturated & Omega3) from meat, dairy, fish, olive oil, coconut, and grapeseed.
My list of unhealthy foods is largely: processed/highly processed foods, industrially raised meats/eggs/dairy, processed carbs, sugar, HFCS, soda, flour, baked goods (sorry), trans-fats, white rice/potatoes. Few vegetable fats (corn, canola, soybean, etc. oils). Allowable in very small quantities, but frankly few of these appeal to me at all after a few years of eating clean.
And the quality-of-life benefits are huge.
The other underappreciated element to fitness is strength training. One article that's been featured at HN before that's particularly good at highlighting what's wrong with conventional wisdom on fitness is "Everything You Know About Fitness is a Lie": http://www.mensjournal.com/everything-you-know-about-fitness...
A still useful definition of eating healthy is to eat approximately the correct amount of calories.
Obviously the what is also going to have impact, but it is easy to observe that the great majority of people are not walking around with severe nutritional deficiencies.
Debatable. They clearly have enough calories, but you need more than just that to live and be healthy. I would strongly argue that omega-3's and vitamin D3 are essential nutrients that a substantial portion of the population are deficient in.
I said severe because there are clear complications for severe deficiencies (rickets, scurvy, etc.). The science surrounding correct levels and consequences of not quite correct levels of such nutrients is much less settled.
So among the group of people that are not basically falling apart from a nutrient deficit, the ones that eat about the right amount of calories tend to be (quite a lot!) healthier than the ones that eat far more or far less calories.
You have to die of something. What's important is years of high-quality life, rather than merely avoiding death from any specific ailment. And of course, quality is ultimately a subjective measure. All the behaviours that you must conform to, to avoid these specific deaths, may themselves detract from your quality of life.