For successful intense training or competition you should top up your energy levels before you start and refuel during exercise with carbohydrates thatrsquos why powerbar invented the first energy bar in the world back in 1986 suggested usage consume 1 wafer within 60 minutes before sport andor consume up to 90g carbohydrates per hour during sport depending on the intensity and duration 1 powerbar energize wafer delivers about 27g carbohydrate