It’s that time of year again–when people make New Year’s resolutions about eating healthier. Reading more books. Starting a garden. Jogging around the block every day. Here’s an important resolution for everyone: drink more water and less coffee.

Why? There's plenty good reasons.

Drinks such as coffee, milk and juice all require water from the body to be properly digested. Alcohol and some medications can lead to increased fluid loss as well. In the end, there is no substitute for water in providing the body what it needs for optimal cellular function.

The body is made up of about 70 percent water, which plays a vital role in nearly every bodily process; water is essential for proper digestion and circulation, numerous chemical reactions, nutrient absorption, waste elimination and flexibility of the blood vessels. It regulates body temperature and benefits the skin by acting as an internal moisturizer, keeping the skin moist, supple and clear, as well as preventing premature aging due to toxic buildup.

In many cases, when people are ill, eating or drinking anything is probably the farthest thing from their minds. Yet it’s vital to maintain a good level of hydration to help the immune system fight off infection and assist in eliminating byproducts of any illness. Dehydration weakens the body’s overall immune system and leads to chemical, nutritional and pH imbalances, which can eventually cause sickness and premature aging.

No matter what your New's Years resolution might have been, a nice simple one to keep is to simply drink more water. Sure, it's not as fun as some of those other resolutions, but it will keep you healthier, which should help keep you happier.