According to the text, glycine is an amino acid that can be found in various foods such as cabbage, asparagus, watercress, dried seaweed, spinach, dairy products, legumes, meat, soybeans, pork salami, coffee, tea, soups, oatmeal, protein shakes, yogurt, pudding, carob seeds, sesame seeds, pumpkin seeds, and pistachios. It is estimated that the average person consumes about 2 grams of glycine per day from food sources. Some of the highest sources of glycine include gelatin (from swine, soy protein, and skipjack) and gelatin desserts. Additionally, glycine can also be added to foods and drinks such as coffee, tea, soups, oatmeal, protein shakes, yogurt, and pudding as a supplement.