Woman holding a glass of water.
By now, you know that drinking water and staying hydrated is great for you: Your skin looks better, your digestive system is more regular and it helps you stay generally healthy. But did you know water can also act as a magic elixir for weight loss?
Well, not quite. While water isn't quite at, say, Ozempic levels of weight loss aids, staying adequately hydrated can play a key role in your weight loss goals.
Find out exactly how hydration factors into weight loss, and how much water you should aim to drink to lose weight.
Related: The Best Fat-Burning Foods
How Does Hydration Factor Into Weight Loss?
There are several reasons why staying hydrated can help you shed pounds. In technical terms, Costa says, "Increased water consumption can aid in weight loss in two ways: by reducing hunger and promoting the breakdown of fat (lipolysis)."
One way that hydration can help curb hunger is by preventing your brain from tricking you into thinking you want a burger when the real issue is thirst.
"Dehydration and even mild thirst can often mask as hunger, sometimes resulting in overeating," Werner explains. "Drinking enough water may suppress the appetite and keep you full, which leads to eating less. This is particularly true when consuming water before a meal."
Additionally, staying hydrated with water instead of other sources can provide a boost to weight loss in another way.
"By replacing some of our favorite high-calorie beverages, such as sodas, juices, sports drinks and alcoholic beverages, with water, we will naturally start to decrease the overall calorie intake we get daily, assisting with weight loss," Kristen Wright, RD, Employee Wellness Dietitian, Houston Methodist Willowbrook Hospital, says.
However, don't expect a miracle overnight just because you're filling your coveted Stanley tumbler with agua. "Increasing water intake is just a small piece of the puzzle for weight loss," Mussatto notes. "You will still need to have some calorie restriction along with increased physical activity as simply drinking more water will not be the biggest factor for a major change in weight loss."
How Much Water Should Someone Drink if They're Trying to Lose Weight?
This depends on how much you weigh, so it varies from person to person—but there is a great general guideline to figure out your perfect amount of H2O daily.
"Many health authorities suggest a minimum of eight 8-oz. glasses of water (around two liters) daily, but this is not a one-size-fits-all rule," Kelsey Costa, RD, registered dietitian for the National Coalition on Health Care, tells Parade. "Another general rule of thumb is to consume 0.5 to 1 ounce of water per pound of body weight."
In terms of general water intake, Costa says that aiming for a baseline of one to two liters a day can be helpful, especially if you chug some of that before meals. Brittany Werner, RD, registered dietitian and director of coaching at Working Against Gravity, cites a specific study that notes that drinking water before eating can help your stomach feel fuller, thereby helping curb your appetite somewhat.
"This equates to a minimum of approximately 34 to 67 ounces of water per day," Costa notes. "However, these are only general guidelines, and it's important to individualize your hydration based on your unique needs and lifestyle."
Some may need even more water, registered dietitian and author Kim Shapira, RD, notes.
"If you're somebody who works out in extreme heat for two hours or more, or even lives in extreme heat, you're gonna have to increase your water intake," she says. "Drinking this amount of water every day will help you lose weight. When you don't drink enough water, your body doesn't properly filter and hold onto weight. I like to call water 'the secret sauce.'"
Also, don't forget that water isn't just for drinking. "Water and other beverages should make up 80% of our fluid intake," Cheryl Mussatto, RD, registered dietitian at Eat Well to Be Well says, "with the remaining 20% coming from water-rich foods such as fruits and vegetables."
What Are the Signs That Someone Is Not Drinking Enough Water?
Staying hydrated isn't just good for your weight loss goals (and your supple skin!)—it's also crucial for your basic functioning. According to experts, signs that you may be dehydrated can include:
Bad breath: If you have halitosis, it can be from not drinking enough.
Brain fog and confusion: Dehydration can hinder your attention span, focus and cognition.
Constipation: If you're dehydrated, your bowel movements may be irregular.
Cramps: You may experience muscle cramps if you're dehydrated.
Dark-colored urine: If you're drinking enough water, your urine will be clear to pale yellow.
Dizziness: You may feel dizzy or light-headed if you're experiencing severe dehydration.
Dry mouth: This one is a bit obvious, but if your mouth is persistently dry, you'll want to whet that thirst to wet your mouth.
Dry skin: Your skin may feel tight, flaky or itchy if it's noticeably dry. If it's caused by dehydration, no amount of moisturizer will fix it unless you get hydrated from the inside first.
Elevated heart rate: According to Werner, dehydration can lead to an increase in heart rate as the body works harder to pump blood with reduced blood volume.
Fatigue: You may feel tired or lethargic.
Frequent headaches: If you have headaches that won't go away often, try drinking more water and see if that helps.
Reduced urination: If you aren't drinking, you aren't peeing!
Thirst: Feeling thirsty is a sign that you're already mildly dehydrated, so drink up.
Weight gain: If you're chronically but mildly dehydrated, Costa says you may gain weight due to an imbalance of the hormone angiotensin II, which regulates body fluids.
Drinking Too Much Water Can Have Serious Consequences
Yes, it is. And in fact, drinking too much water can have very serious consequences.
"Overconsuming water can be a life-threatening event that can lead to hyponatremia, or water intoxication, causing brain cells to swell. That puts pressure on the brain," Mussatto says. "Water intoxication is a dangerous dilution of the body’s fluids resulting from excessive ingestion of plain water. The mineral sodium is the electrolyte affected most by water intoxication since sodium is essential for keeping the body’s fluid and electrolyte balance."
Initial signs of hyponatremia can be tricky since they mimic symptoms of a lot of other conditions, but they may include confusion, disorientation and headaches—all symptoms of dehydration! Other symptoms include nausea and vomiting. If untreated, hyponatremia can cause seizures, coma and even death, Costa warns. If you think you've overhydrated, seek medical attention immediately.