One serving is three blocks, or half of a tube. During your workouts lasting longer than an hour, we suggest eating 2-3 blocks every 20-30 minutes. If you tend to have stomach issues with chews, eating less than 3 blocks at a time may be more manageable. The key is once you begin eating blocks, or any fast-acting energy, you need to continue consuming them throughout your workout. The sleek packaging makes them easy to slip into your jersey pocket and eat them on the go!