How Water Weight Affects Weight Loss

From MyFitnessPal, written by BY TRINH LE, MPH, RD

When you’re working toward a weight-loss goal, stepping on the scale and discovering you’re a few pounds lighter can motivate you to keep focusing on healthy habits. However, fluctuations on the scale could be due to water weight and not fat loss.

Here’s how to know if your efforts are paying off and why you should be mindful when you step on the scale.


What we see as a decrease in body weight is a change in muscle, fat and water. Water makes up 60% of your body weight, and it’s one of the first things you lose.

Fat mass doesn’t change overnight, but you can lose as much as five pounds of water in a day. Average 24-hour urine loss ranges from 800–2,000 milliliters of fluid or about 1.8–4.4 pounds because water is heavy. It sounds drastic but as you lose water, you’re also replenishing it through food and drink. By contrast, it’s virtually impossible to burn off a pound of fat in a day. Let’s do the math: A pound of fat is 454 grams, and assuming each gram of fat yields 9 calories, you’d need to burn 4,086 calories to lose one pound. Few activities can stimulate that level of calorie burn.


Most people with a weight-loss goal eat fewer calories, carbs or both and exercise more often. When you cut calories and carbs for weight loss, the first place your body dips into for extra energy is glycogen (Think: stored carbohydrates), which is housed in the liver and skeletal muscles. Glycogen is usually stored with lots of water, so tapping into it releases a lot of water. Exercising more often will also cause you to lose water weight through sweat. You’re still losing fat, but at a slower rate than water.


Certain foods and nutrients can shift your body’s water level short-term. They include:1


As mentioned above, cutting carbs releases water because it causes your body to tap into its glycogen stores.2


If you bump up protein intake to enhance weight loss, you will lose more water through urine. Protein breakdown creates urea and other nitrogenous wastes that require water to remove them from the body.

3 – SALT

Your body retains water to dilute excess sodium from a high-salt diet. While this has a small effect on water weight, it can harm your health over time. Holding onto excess sodium and fluid increases your blood pressure. Your heart has to work harder, causing wear and tear on your cardiovascular system. Whether or not water weight is on your mind, it’s a good idea to eat less sodium.4


Caffeine is a mild diuretic, meaning it increases urination and water loss. Research shows this effect is strongest in individuals who are new to or deprived of caffeine. If you regularly caffeinate, drinking coffee and tea does little for your water weight.5


The classic hangover headache is partly due to dehydration. Alcohol prevents the release of vasopressin, a pituitary gland hormone that regulates how much water is lost through urine. Water loss (and dehydration) is a side effect of drinking alcohol, though it’s definitely not a good solution to get rid of water weight.6


Intense workouts, especially those in hot and humid weather, increase our sweat rate and water loss. This is why some long-distance runners weigh themselves pre- and post-run to determine how much fluid they should drink to replace sweat loss. It’s known that even mild dehydration can negatively affect exercise performance.


Water weight can be annoying since no one likes feeling bloated, but it’s thankfully a short-term issue. It’s normal for your water weight to fluctuate from day to day. This is why weighing yourself weekly is better than weighing yourself daily when you want to gauge progress. Long-term changes in body weight result from change to lean muscle or fat, which is what you want to see. Finally, abstaining from water won’t help you lose weight — the opposite is true. Good hydration aids your weight-loss efforts by curbing hunger and enhancing fat burn.

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