Contrary to what other people are saying, what worked for me was to use my meter. When I ate lower amounts of protein, my FBG dropped by quite a lot. I went from 100-110 FBG to 70-80 FBG, just depending on the amount of protein. I was still eating quite a lot of carb (but mostly fiber). Net carbs were around 20-30g.

I'm not positive about what happens if you drop it all at one meal. I know BG and insulin both go up to deal with the protein, but nowhere near the amount of carbs. However, they stay up longer. So perhaps the best time to meter is just before your daily meal.

Now, don't obsess over the meter, but it is helpful to track what is happening in your body when you make changes. Just... be rational with its use. Day to day fluctuations happen and meters aren't all that precise. If you're the sort to get knotted up over that, then this advice isn't for you.