While non-impact carbs don't affect FitSpresso bloodstream sugar levels levels, they still contain calories (except fiber, which isn't digestible). A person who eats lots of non-impact, carb-containing foods is still getting all of the calories a good equivalent number of regular carbohydrate food! 
https://www.mid-day.com/amp/lifestyle/infotainment/article/fitspresso-reviews-customers-latest-update-and-warnings-is-fitspresso-coffee-23344928