This is what I satisfy my sweet tooth with in this hot weather. It tastes so good and refreshing I could not but post it.
100g no-fat Greek yogurt
Juice of a lemon wedge
2 kiwi fruit, cut into small cubes or pureed
5 medium size cubes watermelon (I used frozen as the yogurt freezes faster with them), smashed
4-5 drops stevia extract
Mix everything, put into freezer, stir from time to time till gelato consistency.