White kidney bean extract can act as a carb blocker directly upon its appearance in your body. However, it would take at least a week for your body to start blocking the amylase action and giving less sugar to your intestine to absorb and metabolize. Carb blockers have high effects in blocking long-chain carbohydrates taken by foods and beverages. You need to follow a healthy diet with lots of proteins and less fat to start seeing feasible weight loss results. Carbohydrate blockers work better when Ketones are present in your blood so consider taking the Raspberry Ketones supplement for faster results.