For overweight and obese men and women forty years of age and older, drinking a pint of water just before eating will reduce the amount of food they eat. When combined with a reduced-calorie diet, drinking water before meals results in more weight loss than only dieting.
These results were reported by Professor Brenda M. Davy PhD, RD, at meetings of the American Chemical Society in Boston, Massachusetts in August, 2010. The study followed 48 overweight and obese men and women for 12 weeks. Those who drank water before meals lost about 15.5 pounds while the others lost only 11 only.
Drinking cold water with a meal slows digestion until the stomach contents reach normal body temperature. Food in the stomach delays gastric emptying and traps water taken with a meal for several hours. Stomach acid is diluted by water taken with meals. Acidic stomach fluids can easily rise in the esophagus causing heartburn symptoms.
It is best to stop drinking water 15 minutes before a meal. This lets the water to leave the stomach before food is eaten. Ellen White, a 19th century health reformer gives this advice about drinking water with meals:
“Many make a mistake in drinking cold water with their meals. Food should not be washed down. Taken with meals, water diminishes the flow of saliva; and the colder the water, the greater the injury to the stomach. Ice water or ice lemonade, taken with meals, will arrest digestion until the system has imparted sufficient warmth to the stomach to enable it to take up its work again. Masticate slowly, and allow the saliva to mingle with the food. The more liquid there is taken into the stomach with the meals, the more difficult it is for the food to digest; for the liquid must first be absorbed”. (Counsels on Diet and Food, 106)