There will be those who will hop on here and tell you it's because of the sugars breaking down and your body digesting them quicker etc etc but, in a nutshell, SW's reason for synning blended fruit is because it is way to easy to overconsume and you don't feel as full as if you ate the fruit unblended.
Why are some fruits Free when raw, but have a Syn value when cooked, juiced or pureed?
A: While fruit in its natural form is bulky, filling and often time-consuming to eat, in cooked, pureed, liquidised or smoothie form it makes it very easy to over-consume and is a very effective way of adding a lot of extra energy (calories) in a non-bulky and non-filling way, which doesn’t satisfy your appetite in the same way as eating fresh whole/sliced fruit. Consider eating an orange. Peeling, breaking up the segments and eating just one orange can be a lengthy process. Now think about the juice that orange would produce – it contains a similar number of calories, yet it’s gone in a gulp – in fact it takes 8 oranges to make a small glass of orange juice and it’s not filling in the slightest! It’s all about getting the most (optimum) satisfaction from your foods with Food Optimising. We count juiced, pureed and cooked fruit as Syns to protect your weight losses.