That totally makes sense, as we didn't evolve to eat a lot of food products which are common in today's diet. The more we eat foods that are closest to their natural form the generally healthier we will be.

I tend to agree. There's still so much we don't understand about how nutrition works and the delicate, yet flexible balance of the digestive microbiome — so, it seems we can survive a long time on a wide range of food-like substances, but there's a long-term health consequence to over-reliance on heavily processed food items. A few years ago, I switched to a mostly whole-foods, plant-based nutrition plan, and it's astounding how much of a difference it has made. I shed a lot of excess weight, my energy picked up significantly, and the last time I checked my blood pressure it was at the lower end of the healthy range (where it had been at least at the low end of hypertension before that). I still use olive oil (or, occasionally, avocado oil) and salt — though I should cut back on both — but otherwise, my diet is almost exclusively WFPB.

I do think there's more to it, though, and this is where I fall short. Managing stress is important, but many of us have increasingly stressful jobs, financial worries, lack of social support, and so on. Stress has been shown to be a leading cause of chronic disease, possibly because it drives up cortisol levels and results in non-productive inflammation throughout the body (including in the cardiovascular system). How we perceive stress is a major factor in how it manifests, though, so some of this comes down to shifting our mindset from negative to one of seeing stressful situations as positive challenges and opportunities. But I struggle with that, even though I think I'm a lot better than I used to be in this regard. I also fall short on getting enough sleep, and I really do need to make this a priority. Medical studies have shown that lack of sufficient sleep (7½–8 hours) is at least as detrimental to our health as smoking is in the long run, which makes sense when we recognize that our bodies' repair processes take place mostly when we sleep.

I do try to get a good amount of exercise, too, and I think this is important to overall health and quality of life, and that it plays a role in reducing stress, but on its own I think it's less important than a solid diet, stress management, and sufficient sleep. We keep hearing about the importance of getting enough steps throughout the day, and I don't denigrate the idea that physical activity has significant benefits to physical and mental health, but it's also true that one cannot outrun a poor diet.

If I had to prioritize for myself what I think is important to good health, I'd probably say stress management first (with socialization as a primary aspect of this, and how we perceive of and relate to stress as likewise significant), then a whole-foods diet with lots of fiber-rich foods (fruit, whole grains, vegetables, etc.), then sleep prioritization (though I might rank this equally or even a little more important than diet), and then exercise. I think I do well overall, but I have plenty of room for improvement.

@SpikeTalon I think nutritional values have a lot to do with portion sizes. In general, the more processed the food, the less nutritional value it has, although it retains all the calorie content. So in order to get enough nutrition, the body craves larger portions, and hunger persists, often even after a person is "full", because there is not enough nutrition in the food they are eating, as most of the nutrition is destroyed in processing. Processing food does extend shelf life and increase profits, so most food in the grocery store or from "fast food" outlets are processed to some extent.

We have evolved to crave salty, sweet and fatty foods. In their natural states, foods with those flavors also contain nutrient we need. Food processors take advantage and flavor foods to be salty, sweet or fatty, even though they contain very little nutritional value. They do still contain all the calories though. So, our body craves more food to get the nutrients it needs, and we consume massive amounts of calories, because our body is seeking more nutrition, which leads to most Americans being overweight and with other health issues as they get older, because their diet has insufficient nutrients.

I myself try to avoid foods with any kind of processed sugar(s), just as a starting point for getting more nutrition in my food. Next, I avoid hydrogenated oils, which are in most "fat free" food products, because hydrogenated oil tastes like fat. However, it is more harmful to you body than fat would be in its natural form. For anyone who wants to be healthier, those two things are a great start to eating healthier.