Drinking plenty of water is essential for overall health, and is a great way to boost your weight-loss efforts. But if you’re getting your H2O from cheap bottled water, the bottle itself could pose a problem; Bisphenol A, commonly referred to as BPA, has been linked to obesity, and it’s still found in many cheap plastics. A 2011 Harvard study found that adults with the highest concentration of BPA in their urine had significantly larger waists and a chance of being obese than those without as much of the chemical in their systems. So if you must drink store-bought bottled water, check to see if the bottle is BPA-free. And whatever you do, don’t reuse the same bottle; constantly refilling the same plastic bottle can cause BPA to leak into the water.