As you know if you’ve been following my blogs here on Epicurious, August’s Doable Challenge is to make a series of five small dietary changes that contribute to overall health and may even help you lose weight. On Monday, I covered the first change — eating more fruits and vegetables — and today I want to talk about water. As registered dietitian Ellie Krieger explained when I interviewed her for the challenge, staying properly hydrated can fight fatigue, headaches, and health problems like urinary tract infections. Studies suggest that drinking plenty of water can help you stay slim, too, especially if you swap water for soda, sweetened juices, or other sugary drinks. Krieger says that most people need about 9 to 13 8-ounce glasses of water a day, with half of that coming from straight water — the rest can come from other sources, like milk, smoothies, 100 percent juices, and soups. Even caffeinated drinks, such as coffee and tea, provide some hydration. Watery fruits and vegetables, such as watermelon (91% water) and cucumbers (96% water), and even yogurt (85% water), can contribute to your fluid needs, according to a sidebar to an August 2013 Runner’s World article about hydration. So, here’s your challenge for the next five days: Simply swap one of the healthy hydrators below (or a glass of plain water) for one serving of any less-healthy drink you’d normally have. And tune into your thirst, which Krieger says is an accurate indicator of your need for water (in other words, listen to your body!). Ginger Green Iced Tea Watermelon and Grapefruit Agua Fresca Mango, Berry, and Banana Smoothie Cucumber-Lime Agua Melon Coolers (pictured) See more healthy drink recipes on Epicurious and share your favorites in the comments section (my current fave is seltzer with a splash of pure cherry juice, and I also love Krieger’s suggestion of adding chunks of wateremelon to a jug of water).