According to Dr. Mike Israetel, a sports nutrition consultant and former professor of exercise science at Temple University in Philadelphia, PA, most fruit juices are rich in carbohydrates, making them nearly hard to consume on the keto diet. For example, eight ounces of cranberry juice has 30 grams of carbohydrates. However, he said that if you're drinking the juice as an antioxidant supplement and not so much for its flavor, then it's fine to include it in your diet. Cranberries have antioxidants called flavanoids that have been shown to help reduce urinary tract infections by inhibiting the growth of bacteria that cause these infections. However, according to Dr. D'Agostino, there is no evidence supporting the idea that drinking cranberry juice can prevent or treat urinary tract infections. He also noted that although the fruit contains antioxidants, they aren't present in significant amounts. The best way to get nutrients is through healthy food choices, not supplements. If you choose to drink cranberry juice, do so in moderation. One recommended amount is one ounce per day for adults. That's about two tablespoons worth of pure juice.