The Scientist: Amy Jamieson-Petonic, R.D., is the director of wellness coaching at Cleveland Clinic’s Wellness Institute.

The Answer: Your body is at least 60 to 70 percent water. It circulates through your blood vessels delivering much-needed vitamins, minerals and nutrients to your tissues. As the pressure inside arteries and veins change, fluid moves from inside the vessels to the spaces between tissue cells and back. How hydrated you are, what you’ve eaten, your activity level and where you are in your menstrual cycle (along with a host of medical issues) affect the flow of fluids in this system of dynamic equilibrium.

When you’re approaching your period or have eaten a lot of salt, your body may hold onto—that is, retain—extra water in your tissues, which can make you feel and look bloated. The fluid you don’t need gets excreted in sweat and urine. On any given day, you can fluctuate by 2 to 5 pounds of water.

If you crash diet, exercise like crazy and drop 5 pounds right away, that’s (literally) water weight. You haven’t “lost weight,” you’re dehydrated—and your body will go into conservation mode to reestablish equilibrium. Meanwhile, since your body requires protein to draw water out of your cells, a low-calorie regimen can actually increase water retention. Counter-intuitive as it may sound, if you want to prevent putting on water weight, you need to drink more water. Your body will do the rest.


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