Water is the most abundant substance in your body! On average, body weight is 45% - 75% water. This is equal to almost 10-12 gallons of water! Body composition, gender and age affect the amount of water in each person's body but for all people, water is essential! Every organ, tissue and body cell uses water to function.
In addition to providing an aqueous solution for your cells, water helps regulate body temperature, transports oxygen and nutrients, and carries wastes out! It is found in gastric juice, saliva, urine, blood, and keeps exposed organs, like your eyes, moist.
Under normal circumstances, the average adult loses about 2.5 quarts or more of water through activities like sweating, bowel movements, breathing and urination. As soon as you add physical activity or hot weather into the mix, the rate of water loss increases.
Dietary Reference Intakes (DRIs) advise an Adequate Intake (AI) of 3.7 liters or 125 ounces of water for males over the age of 19 and 2.7 liters or 91 ounces of water for females 19 and older. But you get water from a variety of sources, including the food you eat and beverages you drink -- it is even produced as an end product of your body's metabolism. Keep in mind this rate goes up if you are sick, nursing/pregnant, sweating, on an airplane, exposed to extreme temperatures or exercising.
The American Dietetic Association Complete Food and Nutrition Guide estimates that healthy sedentary adults need to replace bodily fluids at about 9-12.5 cups per day, depending on gender. In addition to fluid intake, 2.33-3 cups will be replaced through solid foods (also dependent on gender) and the remaining 1-1.5 cups will be produced from your body's metabolism.
This is where the question on if drinking cold water will help you burn more calories, since we know that your body uses water to help regulate and keep a steady internal temperature. The amount of calories it would take your body to bring an 8 ounce glass of ice cold water up to body temperature is estimated to be about 8 calories. This is very dependent on your body's temperature and how cold the water is. The reality is that this is a negligible amount in the span of your day, and the act of getting up, walking to your freezer, emptying trays, refilling trays, turning on the facet and the ups and downs from urination will use more calories.
However hydration is important for weight management, and many people find that colder water is more desirable than tepid water, and may increase your water intake. But drinking iced water alone will not have huge effects on weight-loss; overall reduction in calories and increasing exercise, in conjunction with good hydration, is still the best method. So whether you decide on cold water or tepid water, monitoring your water intake is a very vital and an important part of staying healthy.
Emily DeLacey MS, RD is a Registered Dietitian and currently working in Jamaica as a HIV/ AIDS Prevention Specialist. She attended Central Washington University for her Bachelor's Degree in Science and Dietetics and continued on after her internship to Kent State University for her Master's Degree in Science and Nutrition, with a focus on public health and advocacy. She served as a U.S. Peace Corps Volunteer in Malawi 2012-2014 working as a Community Health Advisor in a rural village, immersing in the joys of life without electricity or running water. She has been to 20+ countries and 47 of the 50 states in the US. Traveling, adventuring and experiencing new cultures has made her a passionate advocate for the equality of nutrition and wellness for all people.