Losing weight requires a consistent commitment to several lifestyle choices: Eat healthier, exercise more, get 6-8 hours of sleep a night, and drink lots of water. Not only will choosing water over caloric and sugary beverages save you calories, but water is also essential for sharp brain function, keeping your organs working properly, and exercise recovery — to name a few important reasons. And if you’re reaching for detox water, it can help boost your metabolism and flush out toxins.
But just hearing that you need to drink “lots” of water can be confusing. For some people that could be the standard eight 8-ounce glasses, but others could need a lot more (or perhaps less). We tapped dietitian Jim White, RD, ACSM, and owner of Jim White Fitness and Nutrition Studios, to find out just exactly how much water you should be drinking for weight loss.
For the Average Person
Although everyone has different needs, White says sticking to the oft-recommended amount of eight 8-ounce glasses (64 ounces total) should suffice and can help boost weight loss for the average person or someone just looking to drop a few pounds.
It doesn’t sound like an overwhelming number, but the challenge for most people is drinking enough water in the first place. According to a study by the CDC, 43 percent of adults drink less than four cups of water a day, with 7 percent reporting they don’t drink any glasses of water — yikes!
In general, you should let your thirst be your guide. If you’re still thirsty after chugging 64 ounces throughout the day, make sure you adjust your intake accordingly. But if you’re feeling quenched, be sure not to overdo it; drinking too much water could lead to hyponatremia, also known as water intoxication, where the sodium levels in the body become overly diluted and can lead to swelling in the brain, seizures, and coma. There’s a reason this dangerous practice is one of the 16 Ways You’re Drinking Water Wrong.
If You’re Working Out a Lot
If you’re a big time gym rat or endurance athlete, you’ll need more water than the standard 64 ounces. After a serious sweat sesh, you could be depleting your body of proper hydration.
“The American College of Sports Medicine recommends to drink 16 ounces of extra water before you exercise, and to sip on 4-8 ounces during exercise, and another 16 ounces after exercise,” White explains. “You can also weigh yourself before exercise and see how many pounds you lose. Drink 16 ounces afterward for every pound lost.”
If You’re More Overweight
For overweight or obese people, their water needs are different. White says they’ll need to drink even more water to stay properly hydrated and aid in weight loss. A simple math equation for this is to drink half of your body weight in ounces of water. So if you weigh 180 pounds, you should aim for 90 ounces of water a day.
A study published in the Annals of Family Medicine found that people with higher BMIs were the least hydrated. The study suggested that water is an essential nutrient and may play as big of a role in weight loss as food and exercise. Another study published in Obesity found that overweight adults who drank 16 ounces of water a half an hour before their meals lost three more pounds than those who didn’t, and 9 pounds at the end of 12 weeks.
Replacing caloric and sugary beverages such as soda, fruit juice, and sweetened iced teas with water can also help boost weight loss, White says.
Bottom Line: Shoot for 64 Ounces
Although everyone has their own individual hydration needs, shooting for 64 ounces is a good place to start. Let your thirst be your guide; if you’re still parched after 8 glasses, feel free to drink more (just don’t go overboard).
Another indicator for if you've have enough water is the color of your urine: A pale yellow or almost clear color means you are properly hydrated. Anything darker than a pale yellow, and you need to drink more H2O.
“Remember the signs of dehydration: Thirst, dry mouth, headaches, and in extreme cases dizziness and feeling lethargic,” White explains. “Just a 2 percent dehydration in the body can negatively impact athletic performance.”
There are other factors that could impact just how much water you should be drinking: Sweating more, being outside in the heat, taking certain medications, or drinking alcohol. White recommends to drink one 8-ounce glass of water for every alcoholic beverage you consume, and get plenty of hydrating foods such as watermelon, cucumbers, and celery.
Regardless, a weight-loss program should include around 64 ounces of water — more if you've got a lot of weight to lose or your program involves a lot of working out. So grab a reusable, BPA-free water bottle, keep refilling it, and sip your way slim.