Losing weight can be quite the challenge. And if you’ve recently lost some weight and you want to maintain that hard-won loss—or you want to lose some weight in the future—you definitely don’t want to unintentionally sabotage yourself.
Could drinking more water for weight loss help? And if so, how much is enough?
No one questions that water is important. As Lena Beal, MS, RDN, LDN, a spokesperson for the Academy of Nutrition and Dietetics notes, “Water is an essential nutrient.” It prevents dehydration and helps keep all your bodily functions humming along.
How Much Water Should You Drink for Weight Loss?
But how much should you drink when weight loss is the goal? A common piece of advice is to drink eight cups of water every day. (Remember, you may need more fluids than that, but you can also get fluids from the food that you eat. Research suggests that for most people, about 80% of their fluid intake comes from fluids that they drink and the remaining 20% from the foods they eat.)
So … is that true? Do you need to drink eight cups of water every single day—especially if you want to lose weight? Not necessarily, Beal says, but it’s also not a bad idea to use that as a general goal.
“There’s no one-size-fits-all recommendation for how much water to drink,” says Michelle Cardel, PhD, MS, RD, director of Global Clinical Research and Nutrition at Weight Watchers.
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In fact, she says, you might need to drink more than eight cups of water per day. Some evidence suggests that women should aim to consume about 11 cups of fluid per day—and men about 15 cups. The specific amount of water that you should drink each day will vary, based on factors like your size, your diet, your activity level and even the climate where you live.
So you do want to prioritize drinking water if weight loss is the goal. “It’s important to drink enough water, whether you’re trying to lose weight or maintain your weight,” says Taylor Stolt, RDN, LD, a functional medicine dietitian for Plate and Canvas.
However, you don’t want to go overboard on drinking water in an attempt to trick your body into feeling less hungry so you’ll eat less, either, says Stolt. “Undereating may result in weight loss at first, but over time, your metabolism will slow down, and you’ll have trouble keeping the weight off. Instead, focus on staying adequately hydrated, honoring hunger cues, exercising to boost metabolism and choosing healthy foods that will support sustainable weight loss.”
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Am I Thirsty or Hungry?
About those hunger cues: Could you theoretically mistake your thirst for hunger? Maybe, although experts say there’s not a body of research about it.
Anecdotally, however, some people might confuse hunger and thirst, even though the initial physiological symptoms are different. However, you can wind up with similar symptoms as a result of being hungry or thirsty—like a headache or irritability. You’re grouchy and you have a headache, so you might not be sure if you’re just dehydrated or maybe a little hangry. Or both.
What that means, however, is that it might be easier to start with addressing your possible thirst. “In general, if you’re not sure, it’s not going to hurt you to go for that glass of water,” says Cardel.
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And if you feel better after guzzling some water and don’t feel like you need to eat a snack, that could work in your favor if you’re trying to watch your calorie intake.
If I Want to Lose Weight, Should I Only Drink Water?
When you’re trying to cut back on calories, water’s always your best bet for quenching your thirst and making sure you stay hydrated without adding any unnecessary calories. If you don’t like plain water, try sparkling water or water flavored with fruit like lemon or lime.
Cardel’s current favorite is water flavored with a medley of cucumber, strawberry, and mint. “You still feel like you’re getting something fun or new and different while still hydrating without the calories,” she says.
But some say calorie-free drinks aren’t a bad option, either. A study in the journal Obesity found that water wasn’t superior to non-nutritive sweetened beverages when it came to helping a group of men and women lose weight during a 12-week program.
What you really want to avoid are sugary beverages that contain a lot of calories.
“Common mistakes I see are using sports drinks or other sugary drinks to quench your thirst,” says Stolt. “These sugary drinks will make weight loss and weight maintenance really challenging. Choose unsweetened drinks to stay hydrated and help you reach your health goals.”
Sports beverages were formulated to replace electrolytes lost during intense exercise, but a lot of people drink them when they’ve just been engaging in some mild or moderate activity levels. You definitely don’t want to give up the exercise, but you may be better off drinking water in those situations, according to Beal. “Otherwise, all we’re doing is adding extra calories that we don’t need,” she says.
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Watch out for alcoholic beverages, too, since they can often contain a lot of calories and are notorious for contributing to weight gain—and potentially contribute to dehydration. “People often don’t register the calories that come with alcohol,” says Cardel.
Other ways that people may unintentionally sabotage their own weight loss efforts by drinking their calories:
- Ordering high-calorie coffee drinks and smoothies
- Drinking sweet tea
- Choosing a large drink, instead of a smaller version with fewer calories
- Drinking a high-calorie drink with a meal
Before you grab a bottle of sugary soda or order a mocha Frappuccino, consider whether or not that choice will help you achieve your goals.
“Water can support the weight loss journey when it takes the place of sugar-sweetened beverages,” says Cardel. “It dan deliver hydration without adding calories to a person’s overall diet.”
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- Lena Beal, MS, RDN, LDN, a spokesperson for the Academy of Nutrition and Dietetics
- Michelle Cardel, PhD, MS, RD, director of Global Clinical Research and Nutrition at Weight Watchers.
- CDC. Water and Healthier Drinks.
- Current Obesity Reports. Alcohol Consumption and Obesity: An Update.
- The National Academy of Sciences Engineering Medicine: “Dietary Reference Intakes for Water, Potassium, Chloride, and Sulfate”
- Obesity. The effects of water and non-nutritive sweetened beverages on weight loss during a 12-week weight loss treatment program.
- Taylor Stolt, RDN, LD, a functional medicine dietitian for Plate and Canvas.