The direct link between water intake and weight loss is a topic of debate. While past beliefs that water flushes fat from the body lack scientific support, some studies do show that water can influence your weight in other ways. These are a few things we know about water, hydration, health, and weight loss.
About 55-60% of your body weight is water, which helps with temperature regulation, cardiovascular function, waste removal, and metabolism. To function at its best, the body needs to be well-hydrated.
Due to water loss through sweat, dehydration can quickly set in during exercise – especially in hot and humid weather. Dehydration leads to fatigue and poor exercise performance. This reduces the amount of time and the intensity at which you can exercise, decreasing overall calorie burn.
Drinking large amounts of water can result in hyponatremia (low sodium). When drinking too much plain water, electrolytes (especially sodium) are transported from the blood and tissues into the small intestine, resulting in a dangerous electrolyte imbalance.
One small study showed that following water intake, metabolic rate increases and remains elevated for over an hour. One reason for this increased calorie burn is thought to be the energy needed for the body to heat the water.
Another study, published in the journal Obesity, found that increased water intake was linked to decreased weight, waist circumference, and body fat in overweight women who were on a weight loss plan.
Thirst can sometimes be mistaken for hunger. Water may help reduce hunger, which can reduce overall calorie intake.
Sipping water provides a distraction to reduce mindless snacking.
Replacing beverages that contain calories with water will lower total calorie intake.