While whole grains contain more micro-nutrients, they also contain more fat as well. What one is trying to achieve health-wise is really what should dictate the details of their diet. If you really want a wallop of micro-nutrients, you could just eat meat, as animal tissues store them in abundance. Given that many realize eating meat has its drawbacks, "eating less is better" can't always be fully accepted based on what is known through epigenetics. There are people living in poverty who easily fit the mold of "light" eaters because of circumstances beyond their control, but in poverty situations people are also often malnourished in the sense of being unhealthy, not just underweight. It may be the case for many people that because of genetic predisposition, what they've eaten in their past, or environmental conditions; no amount of "whole" foods can supply their micro-nutrient needs if the overall amount of food is low. Selective human dependance on naturally derived medicine is one example where even a "normal" amount of healthy food isn't enough, let alone a small amount.
These days I eat about 18 meals a week with 3 of them having a major meat component (chicken or fish), 4-6 of them being pizza (2-3 having a single meat topping), and the rest is a combination of whole and processed grain products (e.g. noodles, rice, flatbread, cereal) and vegetables (mostly legumes).