Breakfast smoothie

Hi - wonder if someone can help. I thought I'd found an alternative to protein for my breakfast - a healthy smoothie, which was quick and ideal. However, it pushed my BS way up. It contained low sugar yogourt drink, strawberries, protein powder and lecithin. What could have pushed my BS up to 15? What could I have as an alternative, preferably another type of smoothie? I really can't face meat that early in the morning. Thanks.

I am trying to avoid full fat as I need to lose a lot of weight. Would there be a lot of carbs in a tablespoon of protein powder and lecithin? There doesn't seem to be any carb information on the boxes (I live in Switzerland - very pretty, but a bit behind the times!)