Energy Gels and Bars are popular as they are a potable, easy to consume and provide the energy requirements needed during training or racing. They contain a mix of carbs & electrolytes and may contain caffeine. If your gel is isotonic it can be consumed with out water as is the case with the Stealth Advanced Isotonic Gel.
Once consumed your body starts to break it down almost immediately within the digestive system. Glucose is released in to the blood stream triggering the insulin hormone which allows the body's cells to absorb it quickly. (or store it for later)
This process happens fast- you should begin to notice the effects of the gel within 20mins of taking it. Consuming a gel with water helps it to be digested while keeping the mouth moist.
Energy bars such as the Stealth Juice Bar
Very similar to gels with a more concentrated dose of carbs making them slower to digest and more suitable for sustained longer efforts. They must be consumed with water and can be used pre-work out to top up glycogen stores. Due to the slower digestion, athletes will find these much kinder on the gut making them the preferred choice for long workouts.
They may also contain a higher carbohydrate content making them a tactical choice for longer races such as marathons or Ironman events where an athlete can a carry a higher amount of carbs using non-isotonic bars in comparison to isotonic gels.