This is a huge problem. Way too much diet advice takes the concept of a "balanced" diet for granted, while descriptions of what that means tend to be at least o

This is a huge problem. Way too much diet advice takes the concept of a "balanced" diet for granted, while descriptions of what that means tend to be at least one of: 1) uselessly vague (eat "a variety" of foods, eat sugar "sparingly", get "enough" fiber, and so on; "eat lots of colors" is actual dietary advice that has been given by credentialed dietitians), 2) driven by some fringe/fad theory of nutrition, or 3) based on unrealistic or parochial assumptions of which foods are readily available/affordable.