How much to bolus for vegetable broth?

I think you might be expecting a bit much of your meter - remember, it thinks it's testing blood & working out your glucose, that's completely different to working out the carbohydrate content of soup/broth.

@mahola is right, if you are doing a home made recipe, you need to weigh your ingredients and work it out as you go. Or there's an app called cook & count which is supposed to be quite helpful for home cooking - http://www.drwf.org.uk/news_uk/new-...hydrate-content-home-cooked-food#.Vy9OsdR4WrU

Potato carrot and onion are very carby and even more so when cooked. Perhaps strain the broth part into a bowl, weight the veggies alone and then throw them back in the broth. At least you'll get a better guesstimate. I always weighed the food while making it but every ladle holds different amounts so it's hard to judge but you can at least get closer weighing the veg

I've been told that the meter can be used to, for example, check if a drink in a pub is full-sugar or not. However, I understand the guidance is that you can never use it as an exact figure. You could maybe use the carbs and cals app/book to get an estimated figure. I believe they have vegetable soup in there. It means you'd just have to weigh the whole meal which should make life easier. If I was doing this, I would weigh the potatoes I use before I add them in (raw potato = ~17g/100g) and then maybe add a few grams on for the lower carb veg like the carrots.