It matters a lot how good is the food you eat, and how efficient is your digestion. But it still isn't enough to guarantee health. It is the smallest piece of the puzzle - your cellular metabolism - that ultimately determines how good you feel, and how long you live. As your cells assimilate small molecules of proteins, fats and carbohydrates broken down by digestion - i.e. amino acids, fatty acids and monosaccharides - the question of whether they will be able to use them efficiently for…