Does blueberry juice make you fat?

No: Excess calories can cause you to gain weight. Blueberries are no more calorie dense than other fruits. Juice, in general, is high in sugars. Consider just eating the blueberries, and measure your portions to count calories.

Too much might.: Whenever we make a given fruit easier to ingest, such as when we drink blueberry juice as opposed to eat actual blueberries, the convenience leads to overdoing it. I'd imagine that calorie-wise you're taking in more in the juice than you would in the actual fruit if you were just eating blueberries.