Most people seem to believe nutrition consists of objectively good or objectively bad foods. They miss that it’s all contextual. If you just finished a workout then sugar is really beneficial to you since it’s consumption foes directly to the muscles and doesn’t rise insulin levels. Gatorade is great if you’re working out, it’s horrible for your health if you’re sedentary. The same can be said with simple carbs and fats. Complex carbs and proteins (such as casein protein) are also best consumed when you’re resting (both brain and muscle benefits), but if consumed after a workout it will cause you harm since it will take hours for the body to absorb it when you need immediate nourishment.
Another aspect of it is that you need to know how to combine foods since they’ll have a different nutritional effect. For example: Most people eat salads as a way to avoid fats and hopefully lose weight. Many of the nutrients from vegetables can only be accessed with saturated fats however, therefore high fat dressings, olive oil or nuts will actually increase your nutritional absorption of foods. Or combining calcium with zinc will cancel out the absorption of zinc.