Although generally used to maintain healthy weight, a carbohydrate blocker can affect your energy, concentration, sleep, and blood sugar. Keto diet plans are a good example of a metabolic boost. Atkins is another diet that aims to work as a protein world carb blocker. Guava leaves aid in maintaining a healthy weight by preventing the complex starches from being converted into sugars. It’s a metabolic booster for this purpose. The carbs must be broken down in the liver for use by the body and guava leaves prevent the transition of carbohydrates to usable compounds.