Drinking More Cold Water Burns a Few More Calories

You will see advice from almost every source that you should ensure you are drinking enough water when trying to lose weight. Substituting plain water for sugar-containing beverages is one way to cut calories. Some studies say water, especially cold water, has additional weight loss effects in reducing the calories you eat and helping you burn fat.

Cold Water and Burning Calories

One theory is that your body must burn calories to bring cold water or room temperature water up to body temperature. This heat creation process is called thermogenesis.

A small study from 2003 claimed drinking water may help you burn a few more calories each day. The study authors calculated that people burn 50 calories per 1.5 liters of water. This would be about 17 calories per water bottle (0.5 liters), the equivalent of 4 M&M candies. The authors estimated that a third of the calories burned after drinking are due to thermogenesis (5 to 6 calories per water bottle).

A follow-up study disputed the impact of thermogenesis. Researchers found no difference in calories burned at rest versus calories burned after drinking room temperature water. Participants did burn more calories after drinking cold water (37 degrees F), around 15 calories per water bottle, which was much lower than anticipated for the temperature difference.

Both studies suggested that the number of calories burned after drinking water is only partially influenced by temperature. Most of the energy expenditure seems to come from the body working to balance fluid, salt, and sucrose levels after the influx of extra water.

With all things being equal, if you prefer cold water, go ahead and chill it. Few people find room temperature water as palatable, and you may drink less of it. The most recent American College of Sports Medicine guidelines on hydration recommend that athletes and people engaged in exercise drink cooled water, as they will want to drink more of it.

How Much Water You Need Each Day

How much water you should drink each day, regardless of dieting, is a common question. Apart from the water you get in food, medical references say women should drink between 11 and 12 cups of beverages each day (2.7 liters) and men should drink between 15 and 16 cups (3.7 liters) of beverages. With exercise, you should replenish the water you lose through sweat.

Why Should You Drink More Water When Dieting?

Many diet plans advise you to drink more water when you want to lose weight. Drinking more water doesn't simply "flush fat" as is sometimes claimed, but there are weight loss-related reasons to drink water.

• Drinking a big glass of water whenever you feel hungry and before a meal or snack fills the stomach briefly and makes you feel fuller and perhaps stop eating sooner. Research has sometimes found drinking water to reduce the calories people eat during a meal, but results depend on the context.
• Breaking down body fat and muscle during weight loss produces wastes that must be eliminated through the kidneys. Drinking enough water is important to keep the kidneys functioning to remove these wastes.
• Popular high-protein diets produce more waste products from digestion in addition to breaking down stored fat. Kidney function is even more important when on a high-protein diet.
• If you're drinking plain water, you are less likely to be drinking something with calories in it. What you drink is often a big source of calories. The key is to replace those calories with food that is high in nutrition.

Dangers of Drinking Too Much Water

Don't start drinking an extra gallon of water a day. That can kill you—especially if you are fasting or eating very little. Water taken in must be in balance with body salt—electrolytes. The body needs to maintain salt balance or risk hyponatremia, which can result in a heart attack and even death.

Drinking too much water has resulted in the deaths of healthy athletes. Drinking sports drinks during endurance exercise is meant to replenish salt lost in sweat. People should not plunge into drinking gallons of water a day in hopes of burning a few more calories. Drinking an extra few glasses is fine, but a gallon is too much.

Drinking and Exercise

Exercise such as walking causes your heart rate and breathing rate to rise, and you lose body water through increased respiration and sweat. According to the American Academy of Family Physicians, you should drink a glass of water 30 minutes before a workout, then drink about a cup of water every 20 minutes during exercise. When you finish exercising, drink a glass of water within 30 minutes.

Intense endurance exercise may require a different approach. To prevent hyponatremia, guidelines for the marathon and half-marathon often say to "drink when thirsty" rather than pushing water. Be sure to have access to enough water during exercise so you can drink when you feel thirst.