There's 20 ounces in a G2. They list a serving size as 8 ounces. Meaning there's 2.5 servings per each bottle. 8+8+4=20. But, somewhere, their calorie math got lost.
If there's 20 calories per 8 ounce serving, that leads me to believe that there would be 10 calories per every 4 ounces, right? So...the first 8 ounces has 20 calories. The second 8 ounces has another 20 ounces and the last 4 ounces *should* have 10 calories. That adds up to 50, right?