First I buy a big container of plain, non-fat yogurt, brand or size doesn't matter to me. You can either sweeten it as you eat it, or just sweeten the whole container at once. These directions are for sweetening it by serving, which is 1/2 a cup for me. So to 1/2 c of yogurt, I add about 1 tablespoon of no sugar added fruit preserves. Now you have to read the ingredients since some no sugar added jams add in artificial sweeteners since they're technically not "sugar". Some names they go under are "sucralose" "aspartame", "acesulfame k", "acesulfame potassium", and "saccharin". To me, if you buy those types of jams, why not just buy the presweetened yogurt? So I buy the all natural fruit spread, such as Polaners all fruit spread. Those contain no sugars, but rather fruit juice as a sweetener. The jam pictured here is a natural berry jam from The Maine Diner. But pick a flavor you like. My favorite is blueberry.
Also, I add some frozen berries too. i chose frozen since when you micrwave them for about 20 seconds, it makes some extra juice, which I find makes the yogurt look, well more like flavored yogurt. If you prefer fresh berries, or they're in season that would work too. For a serving I use about 3 tablespoons, or a little less than 1/4 cup.
Mix it all in and enjoy. Now you can play around with different flavors and amounts to your liking, but I feel adding your own sweetener makes it just the right amount of sweet, and your not using the artificial sweeteners which personally, I feel are just ....chemical? Anyway I prefer to stay away from them.
Now for a half cup serving of the yogurt i made here has about 100 calories, 0g fat, 15 g of sugar (all natural, remember that), 4 g of fiber, and 6 g of protein.
For comparison, the average fat free flavored yogurt has about 100 calories, 0g fat, 14 g of sugar ( that is not including all the artificial sweeteners added) 0 g fiber, and 5g protein.
Hope you enjoy and experiment with new flavors!