Because flavored yogurt has tons, tons of sugar!! It is better to buy plain and then stir in your own fruit, granola, etc. and count those calories and macros separately, and/or flavor it with stevia. Greek yogurt has much more protein per serving than regular "diet" yogurt that might have artificial sweeteners, which is why Greek yogurt is recommended.

Compare the sugars in plain yogurt vs. flavored. You will be amazed how much sugar is added!

I eat Liberté vanilla greek yogourt 0% fat...which is 140 calories for 175 g. It's 40 cal more that the nature one.Usually, I eat about 120 g that gives me around 100 cal like the plain one. It's ok to stick at a diet exactly, but if you dont like what you eat, you will not continue. 40 calories is not a big deal... and I chose to eat that one... But, dont add extra calories like that on every thing, because the diet will not work. lolll But because yogourt is very important part of the diet for me (I love yogourt), I prefer it like that.

The nature yogourt, you can mix with a table spoon of low fat dressing, that will gives you your fat and your protein in a salad that will look like a lot of dressing and you will not taste the plain yogourt. Or I mix a can of chick peas with 175 g of greek yogourt, 25 ml. of lemon juice and Mrs. Dash spice. Splited in 2 parts, it makes a kind of hummus that taste very good with veggies. It gives you proteine and carbs, almost no fat.

I dont use any stevia or other false sugar. I dont like the taste. I prefer to put no sugar.