Pure water is the ideal liquid for hydration. However, if you drink pure water along with an unhealthy diet, it may have some disadvantages. For example, if your diet consists primarily of unhealthy food and snacks, drinking pure water will not benefit you much due to the lack of vitamins and minerals in your diet.
Purified water can also be a disadvantage if you exercise in high temperatures, and you are on a no sodium diet. In this rare case, drinking pure water will absorb the salts in your body which can cause serious complications. Always consult a physician prior to exercising on a no or low sodium diet.
As a general rule of thumb, always be sure to eat a healthy diet, including fresh fruit and vegetables. If fresh food is not available, then supplement with the proper daily vitamins so that water can be designated for the job it was meant for – hydrating your body in its purest form.