From a carbohydrate standpoint, it's not too bad as long as you stick to just one tablespoon. The concern I have with it is the Nutrasweet (aspertame). I really don't think it is all that healthy nor is it very helpful if you are trying to lose weight in my opinion. I've read that just that sweet taste can cause your pancrease to release insulin release in anticipation of a coming bloodsugar rise. And it is the insulin that we are trying to control on a low carb diet. If you are loseing weight and don't have any health problems while using it, then I wouldn't be overly concerned. But if your weight loss stalls or you get headaches, the aspertame would be one of the first things that I would cut out.
Why not use whole unsweetened strawberries instead? You can get them fresh or frozen.
The tragedy of science is the slaying of a beautiful hypothesis by an ugly fact. T H Huxley