Nutrition can be described quantitatively as energy-supplying macronutrients (fat, protein, carbohydrates) or qualitatively as non-energy-supplying micronutrients (vitamins, minerals, trace elements). Macronutrients provide energy, and micronutrients are ingested as components of macronutrients to ensure that the “machine” of metabolism runs smoothly and that every organ and cell receives what it needs to function optimally. Hunger drives the food search and signifies the need for energy. In this context, it does not initially matter in what ratio the macronutrients are consumed. Whether these are primarily protein and fat from animal foods or carbohydrates from leaves and roots is not essential; the main thing is energy. However, different micronutrients are bound to different macronutrients in different amounts. A diet that relies too heavily on one macronutrient may satisfy the appetite, but some micronutrients will be missing. This is still one of the causes of the global undersupply of some micronutrients today. To help individuals know how many macro- and micronutrients they need, recommendations for a healthy diet from professional associations. These are not exact calculations but estimates based on healthy populations of how much is necessary to avoid deficiency symptoms. The required amount can vary from person to person, depending on age or physical strain. What is sufficient usually eludes analysis since before the onset of the classic deficiency diseases (e.g., scurvy, rickets), an inadequate supply can already have occurred, impairing organ functions and, in particular, the immune system, thus affecting a pillar of evolution, survival. The second pillar, reproduction, also reacts sensitively to an inadequate supply of micronutrients.