Does Drinking a Gallon of Water a Day Have Benefits? Here’s What Experts Say

5 Health Benefits of Drinking a Gallon of Water a Day

1. It Might Improve Your Metabolism

Anyone who’s ever tried to drop a few pounds knows that, alongside a healthy diet and consistent exercise, hydration is key. Drinking water (approximately 16 ounces) can increase your metabolic rate by 30 percent, according to a 2003 study in the Journal of Clinical Endocrinology and Metabolism.

2. It Might Prevent Headaches

Dehydration is one of the leading causes of that throbbing pain in your skull. Think of a constant stream of water as a measure that helps prevent a headache from developing. (Just be sure you keep sipping throughout the day.)

3. It Can Help Your Kidney Flush Toxins from Your Body

Water helps the kidneys remove wastes from your blood in the form of urine, per the National Kidney Foundation, which notes, "Water also helps keep your blood vessels open so that blood can travel freely to your kidneys, and deliver essential nutrients to them. But if you become dehydrated, then it is more difficult for this delivery system to work."

4. It Helps Clear Brain Fog

According to a 2019 study published in the International Journal of Environmental Research and Public Health, research shows that dehydration has “negative effects on vigor, esteem-related affect, short-term memory and attention” and, “rehydration after water supplementation improved fatigue, TMD, short-term memory, attention and reaction.” Makes sense, considering water makes up 73 percent of the brain.

5. It Helps Keep You Regular

According to the National Council on Aging, water is necessary to keeps things flowing through your gastrointestinal tract to prevent constipation. Why? "It aids in breaking down soluble fiber from your diet to keep your digestion process on track."

Do You Need to Drink a Gallon of Water a Day?

Hydration is crucial, but a gallon is, for most folks, a little more than necessary to stay hydrated. While drinking more water than your body technically requires shouldn’t be bad, a 2010 Dutch study found that drinking more than your body’s required amount of water didn’t have any more benefits than drinking just enough. You should drink when you’re thirsty, and if that means drinking a gallon a day, great. If it means a little less, that’s also great. If you’re not sure how much water you should be drinking, consult your doctor.

Can Drinking a Gallon of Water a Day Be Harmful?

According to the experts at Cleveland Clinic, drinking a gallon of water a day isn't harmful—with a few exceptions. "[For] those who have congestive heart failure or end stage kidney disease, sometimes water needs to be restricted because the body can’t process it correctly." If you or anyone in your care falls into one of those groups, talk to your doctor about how much water you should (or shouldn't) be drinking.

Also be aware of water intoxication, a disruption of brain function, per researchers at the Cleveland Clinic, caused by drinking too much water.

5 Things That Might Happen if You Drink a Gallon of Water a Day

1. You’ll Have to Pee All the Time

This one isn't too shocking: Drinking more water will mean more frequent urination. You’ll also be doing that other bathroom business regularly, now that your body is breaking down its food more easily. And the last bonus? Those frequent bathroom breaks ensure that you’re moving around more throughout the day.

2. You Might Eat Less

OK, so this one might depend on your age. A 2010 study by researchers at the Department of Human Nutrition, Foods and Exercise at Virginia Polytechnic Institute and State University found that, for middle-age and older adults, drinking water before each meal could decrease appetite, while a second study published in 2008 showed that it increased weight loss by 4.4 pounds over a 12-week period.

3. You Might Have Better Workouts

Per a 2013 paper published in the American College of Sports Medicine's Health & Fitness Journal, "Water acts as a transporter of nutrients, regulates body temperature, lubricates joints and internal organs, provides structure to cells and tissues and can help preserve cardiovascular function." Make sure to drink frequently two hours before your workout, every 20 minutes during and directly afterward to keep your body properly hydrated.

4. You Might Lose Weight

"Studies of individuals dieting for weight loss or maintenance suggest a weight-reducing effect of increased water consumption," according to a review in the Journal of American Clinical Nutrition. Think about it: You’re peeing away the extra bloat, you’re eliminating waste regularly, you’re eating less and you’re working out more efficiently. While drinking more water in itself won’t make you lose weight, the positive side effects just might.

5. You’ll Find Yourself Craving More Water

The more you drink it, the more you’ll want it. Luckily, the stuff is free, pure and as evidenced above, the absolute best for you.