Weddingbee boards

How do you make a smoothie low calorie? Seriously, all the "good" stuff I put in it makes it like a 400 calorie meal. For that I can have a turkey sandwich! Here's what I had this morning:

Frozen mango+raspberry (unsweetened), 170 calories

Low fat vanilla yogurt, 120 calories

Soybean protein powder, 1 scoop, 120 calories

Sugar free tang powder+water, 5 calories

Last night I had the same thing but threw in 1/4 of an avocado for some fat. It was post-workout and it just sounded good at the time.

I know these are all "low calorie" items...but am I dissolusioned into thinking smoothies are good meal replacements? Cuz last I checked my traditional bowl of oatmeal has 150 calories and holds me over just as long. Am I missing any key ingredients/ways to cut calories? Any good flavor mixes you want to throw my way? I don't know why I'm craving these lately but I kinda am. Maybe b/c summer is so far away =]