The basic biochemical function of mitochondria is to produce water. We also recycle the metabolic water to produce energy. Once you recycle your metabolic water to produce energy then you have to drink some water or some oil Dr. László Boros: "The most important function of mitochondria, and that's the basic function of mitochondria, is actually to produce water. […] It's not to produce energy. No, no, no. The mitochondria has very little original biological role in generating energy. In evolution it was actually the sun. The reptiles who actually didn't drink water, they were actually making their own water from food. That's why they could propagate in the desert, and they used the sunlight for energy. "Now as we move to the temperate climate we use the mitochondria, we recycle this water, this is why we can produce more energy. But actually the basic biochemical function of mitochondria, and I'd like to emphasize this, as a biochemist, and as a professor at UCLA, is to produce water. This is why you breathe in oxygen, and this is why you harvest food, hydrogens, and you breathe out carbon dioxide, because you don't need the carbons of food, you need the protons, or hydrogens, from food which you attach to oxygen and you make metabolic, or matrix, water. "Now what happens to this metabolic or matrix water, that decides if your mitochondria is producing energy, ATP, or you use this metabolic water as a chemical solvent and you use it for your body's hydration. That's what the animals in the desert do. But obviously they have sunlight so they don't have to produce ATP as much as like we here in the temperate climate." Luke Storey: "So a polar bear then would be not using sunlight to produce energy. […]" Dr. László Boros: "Yeah. That's why they have to eat those big fatty sea lions, because that's the only way they can survive close to the North Pole, simply because they have to generate ATP from their food, and they have to breathe oxygen in, meaning that they produce their own water in their cells, and they recycle that water. This is why they eat snow, because they still have to have water. Once you recycle your metabolic water to produce energy then you have to drink some water or some oil." Dr. László Boros & Dr. Que Collins with Luke Storey @ 49:14–51:49 (posted 2018-10-02)