A "healthy diet" above and beyond the basics cannot be defined and never will be defined because adequate nourishment can be obtained in so many ways. Much of the science of nutrition is dubious and, anyway, nobody reading this website is in any danger of being malnourished. Overnourished, more likely. Americans probably pee out more vitamins and minerals in a week than malnourished African kids get in a year.
In other words, Americans are the last people in the world who ought to fetishize the idea of "healthy" food. That is probably why we are the only people who do.
The nutritional science which has the most value involves diseases of malnutrition, which are absent in the Western world. The knowledge that has general applicability concerns the roles of protein, carbs, and fats in the diet, perhaps the role of vitamins, and the new information about how people become fat.
Furthermore, some foods are disparaged as unhealthy for no reason. Consider steak and burgers, ice cream, and so forth. People say "Eat fruits, greens, and vegetables." Why? They are just sometimes-tasty fillers with minimal nutrients but which can be fun to eat if done right. Is orange juice "healthy"? Depends what you mean. It's flavored sugar water and some people prefer it to plain water. Is chocolate "bad for you"? Of course not. It is wonderful food.
People talk about what foods are "nutritious." In the Western world, that is an absurd notion. Lots of guys in the NBA were raised on Frosted Flakes, Doritos, hot dogs, Coke, MacDonalds, and school lunch slops. Highly nutritious. The only people who should eat brown rice and whole wheat bread are people who prefer the flavor. The only people who should pay any attention to nutrition are parents of growing kids, people who are overweight, and athletes and others with heavy physical work.
In the prosperous Western world, you are not what you eat - so people ought to eat what they like and what they can afford and ignore the health marketing hype and ignore the health superstitions. I can tell you why our family meals consist of what they do: Tradition, preferences, and nothing more.
Does Classifying Food as 'Healthy' or 'Unhealthy' Miss the Point? A handful of experts weigh in on a survey of nutritionist and consumer perceptions.
What do/did traditional cultures eat? One quote:
Modern investigators find it hard to accept the fact that groups exhibiting superb physical development and perfect health ate liberally of the very dietary component that modern nutritionists have demonized: Saturated animal fat.
Also, the traditional English country diet: Bread, cheese, and ale
