From my understanding: we extract many micronutrients from food by having bacteria in our digestive tract pre-process the food.
When you eat primarily eat junk food for a long time, the bacteria die of starvation. Once this happens it's hard to get them back and you are crippled by not being able to fully digest healthy food to its full potential.
TL;DR humans need to consume more than just calories and protein
why use a forever pan when you can have forever chemicals?