You hear it all the time: “Drink eight glasses of water every day!” Adequate water intake is vital to everyone, but it’s even more important when you’re trying to lose weight. If you’re wondering what all the fuss is about, check out these five reasons that drinking water will keep you healthy and help you shed pounds.

You will consume fewer calories. Most of the things you drink probably contain calories, and if they contain calories you’re in for insulin spikes and crashes. Replace sodas, juices, and sports drinks with water, and you’ll consume fewer calories throughout the day.

You can exercise longer and harder. If you’re adequately hydrated before and after a workout, you can often avoid muscle cramping. You might find that you can get through your workouts more easily, or even add time or difficulty to your exercise routine.

You will feel full longer, and eat less. The brain often mixes up thirst and hunger signals, making you believe you’re hungry when you’re really just dehydrated. This can lead to over-eating at meal time or snacking when you aren’t really hungry. Plus, if you drink a full glass of water before each meal, your stomach will register as “full” sooner, saving you calories at each meal.

You will improve your digestion. Water keeps your digestive system running smoothly, by helping to break down food and move it efficiently through your intestines. In particular, you need extra water if you’re following a high-fiber diet, because fiber depends upon adequate water for digestion. Fiber keeps you feeling full longer, and helps to prevent constipation, so make sure to include plenty of fiber and water in your diet.

You will stay sharp and focused. Water helps to transport oxygen to the brain, to ensure that it functions at its best. When you become dehydrated, you feel cranky, fatigued, and stressed. Since these emotions often lead to overeating or avoidance of exercise, staying hydrated is often the key to keeping your focus on healthy eating and exercise goals.

So how much water do you really need? Each of those eight daily glasses should contain about eight ounces of water. But if you’re working out heavily, or it’s extra hot outside, add an extra glass or two. Keep a reusable bottle near you at all times, and sip throughout the day, and pretty soon hydration will be an automatic habit that you don’t have to remember anymore.