Surpisingly, the best indicator for a healthy diet is not calories, or nutrients, but simply: Are you cooking your own food? This video shows the relevant science, along with a frightening look into the food industry.
I like the fact that the author rightly differentiates between processed and highly processed food; I have absolutely no objections to stuff like frozen foods (they are frozen so quickly that the structure is not affected, and they are frozen so freshly that they actually contain more nutrients than the ‘fresh’ vegetables which have been transported all over the place). Things like canned tomatoes are a blessing, milled flour (careful, though, not too much white flour). Puffed pastry -I tried to make my own once, and it’s a huge pain!