Unfortunately the very process of making a smoothie tends to destroy the natural dietary fibre in the fruit that slows down the digestion process of the fructose in the fruit. Thats what makes them taste so good. The downside is that a smoothie has higher GI load than just the fruit, and will lead to higher and faster bgl spikes.
Warning: Inocent smoothies are now marketed by the Coca Cola company. We no longer know what gets put into them. A serving of Innocent smoothie has (typically) 43.3g carbs, and 36.5g of sugar.There is apparently very little else in it. some salt, some fibre, a tiny amount of protein, and no trace minerals or vitamins listed,
The Daily mail gave an analysis of an innocent smoothie that apparently shows it has 30% more sugar per 100 ml serving than standard coke.