For people who are overweight, drinking a glass of water on an empty stomach can slightly boost calorie burning, but this doesn’t happen in people with normal weight.

When overweight or obese people drink a glass of water on an empty stomach while sitting still, their body burns a few extra calories, possibly because the water makes their cells swell and wake up their metabolism.

Drinking a large glass of water on an empty stomach can make your body burn a few extra calories, especially if you're overweight, because it tricks your cells into thinking they're hydrated and need to work harder.

When you drink water instead of sugary drinks while resting or walking, your body burns more fat because sugar in drinks tells your body to stop burning fat and start storing it.

When you drink water instead of sugary drinks while resting or doing light exercise, your body burns more fat because sugar in drinks tells your body to stop burning fat.

When you drink water instead of sugary drinks, your body burns more fat, especially if you haven’t eaten recently or are doing light exercise, because sugar in drinks stops your body from burning fat.