Combine the juice, avocado, yoghurt, xylitol, tahini and lemon juice and puree until smooth. Adjust the colouring with a drop of green food colouring, if preferred.
Divide the berries between 12 ice lolly moulds. Pour the prepared mixture into the mould and use a skewer to release any air bubbles inside each lolly mould that might have been caused by the berries being piled inside.
Freeze for 40 minutes. Add an ice lolly stick to the center of each lolly and freeze for at least 5 hours or overnight.
To easily release the lollies from the moulds, quickly dip each mould in some hot water for 2-3 seconds. This will slightly melt the outside of each lolly and allow it to slide out easily.
Smaller berries like raspberries and blueberries can be used whole but if you are using strawberries then cut them up into bite-size chunks.