Sooner or later during your stay in Guatemala, you'll meet traditional Guatemalan refreshing drinks. Usually, they provide them with your daily menu meal in some of the eateries (comedores). There are several drinks of that type: rosa de jamaica (hibiscus cold tea), horchata (rice with cinnamon), tamarind or other fruit juice.
Those refreshments were here way before soda drinks, and many Guatemalans stick to them, knowing high sugar content in sodas. Therefore, when eating out ask if the menu meal is accompanied by some of those and choose. Or even better: look for them in local stores, there are already partly prepared concentrates for a daily use. Rosa de Jamaica comes also in dry flower version, you simply have to put that into a boiling water, add sugar and other spices and you can enjoy.
Photos below: Horchata ready to be used, rosa de Jamaica, the flower of hibiscus.