“A 10-pound weight loss is mostly from water or stool being eliminated, and is not body fat loss,” says New York-based nutritionist Millie Shedorick, R.D. “Water weighs approximately eight pounds a gallon, and this rapid loss of fluids can lead to dehydration.”
H2O, of course, is crucial for physical function. It eliminates toxins, delivers nutrients, facilitates digestion, etc. When your stores of agua are depleted, you’ll likely have to contend with side effects like headaches, constipation, muscle cramps, and low energy. All of which hinder your ability to work, exercise, and enjoy life in general. (Work towards your weight loss goals with these moves from Women’s Health’s Look Better Naked DVD.)
“You’ll naturally find that you move around less—fidgeting, standing up, and anything other than purposeful exercise decrease,” says DeFigio. Your calorie-torching power, in the meantime, will suffer.