Why not drink yogurt on an empty stomach? This is because the PH value of human gastric juice is usually between pH 1-3, and the fasting pH value is below 2, while the pH value of active lactic acid bacteria in yogurt is above pH5.4. If you drink yogurt on an empty stomach, lactic acid bacteria are easily killed by gastric acid, and their nutritional value and health care function will be greatly reduced. If you drink yogurt after meals, the gastric juice will be diluted and the pH value will rise to 3-5. This environment is very suitable for the growth of lactic acid bacteria, especially drinking yogurt within 2 hours after meals, and the effect is the best. The best time to drink yogurt is within two hours after a meal. From the perspective of modern nutrition, the best time to drink milk is before going to bed at night. Medical chronograph tests show that the concentration of growth hormone in human plasma will reach its peak after deep sleep at night 1 hour, when the human body is often in a hypocalcemia state. In order to supplement blood calcium, the body should adjust the nutrition in the body and transfer some calcium from bones into the blood. In the long run, bones will become loose due to calcium deficiency, especially in the elderly. If you drink milk at night, you can supplement the demand for calcium in the second half of the night and avoid the loss of calcium in your bones. In addition, there is a biochemical substance in milk that makes people sleepy-L-tryptophan, and a substance similar to morphine has sedative effect, so milk has hypnotic and sedative effects. If you drink milk half an hour before going to bed, it will help you sleep. According to the research of foreign medical scientists, drinking fresh milk before going to bed can effectively prevent the formation of gallstones. Its principle is that milk can stimulate gallbladder emptying, making it difficult for bile to accumulate and concentrate in gallbladder, thus avoiding the formation of small crystals in gallbladder and preventing gallstones.