A niche is a small, protected area where one can reside and develop, primarily protected from competition. The ecological niche represents a space designed to ensure survival and reproduction, while the nutritive niche ensures the supply of essential nutrients for survival and reproduction. Evolution has helped living things adapt to niches that have advantages in the search for food because they contain essential nutrients. Such niches are either already present or adapted to their inhabitants’ needs, also called niche construction. The rainforest of our early ancestors was such a niche that allowed them to live and survive there for a long time. The supply of micronutrients was secured, albeit in significantly smaller quantities than would be sufficient for today’s people. Insects, such as those still consumed by indigenous peoples in Africa, were an important source. But how could the supply of micronutrients be ensured? Here, too, evolution has played a role by leading to the selection of traits that could specifically recognize micronutrients (provitamin A) or favor their biosynthesis (vitamin D). Unique micronutrient niches also developed when an originally possible biosynthesis was no longer available (vitamin C) or when a micronutrient had to be particularly protected (folic acid). More recently, lactate tolerance made it possible for adults to consume milk. However, a niche can also harbor the risk of losing adaptation due to reduced food, which is typical of the niche due to climatic changes or competitors. Still, the adaptation of the niche inhabitant to this food will not change. The consequence is that diseases or particular vulnerabilities arise, and this niche inhabitant becomes extinct, as Neanderthals’ example shows. Or he manages to adapt and accept new food, as the development of humans shows. What is the significance of niches that appear to have been formed by natural selection for humans living today? Are they harmful, and should they be actively changed, or is there an advantage behind them that we are unaware of? What are the arguments for or against outsmarting evolution by using modern methods (genetic engineering) to correct niche constructions we interpret as “harmful” (e.g., disadvantages of fat storage modification, differences in folic acid metabolism)? The reason for such niche constructions may not yet be apparent, but it could also have advantages.