Thanks Scott am Mel, guessing I actually have to tell the libre how many carbs and how much bolus, something I dont do at moment. I simply use the libre to tell me my interstatial fluid reading
The gingerbread man is definitely useful for keeping track of iob, but the other good reason for entering bolus and carbs on the libre reader or the phone app is that, although it isn't that useful "in the moment" for seeing what is going to happen in the next few hours, it's very useful when you download it to the libre program on the pc. It produces a whole lot of reports and you can view daily graphs which show peaks after meals.
I spent a bit of time looking at mines, had a look at the ones which showed the smallest spikes, looked at how far I'd pre-bolused, how much insulin, how much carbs, and also looked at the ones which went way wrong.
Doing that made it a lot easier to say, ok, the graphs from my recent past involving real actual food, show that a meal of that size with x u, y minutes before the meal worked out well, so I'm going to keep that in mind for other meals. Of course, it doesn't always work all the time, but it gives a lot of pointers we wouldn't otherwise have.
If you bling libre up with one of the transmitters we've been talking about, entering carbs and bolus is also really useful "in the moment".
The apps do a "predictive simulation" based on your ratios, correction factor, bolus and carbs, so as well as seeing the live 5 minute blue dots, it projects the graph out into the future with purple dots and makes an educated guess as to where you're going.
They can be a bit hit or miss, takes a while using it to decide which projections to trust or not, it's a bit like calling an election result at 2am, they will update every 5 mins, but all in all, they provide some useful clues on where we might be going. I've often corrected or eaten based in part on what the prediction is saying.
I've put a pic below to show what it looks like - remember that this isn't from some really expensive sci-fi gadget, it's from a libre sensor, which I now get free on script, with a 100 quid transmitter on top which has now lasted for a year, sent to a free app on a 95 quid phone.
The graph show 7 u about 25 mins before a 75 g meal at noon, pretty sure there was some low gi wild rice in that, and a yoghurt, hence the dip down to touching 4 before a rise back up to 4.5 at 12:45.
The prediction then kicks in, the purple dots. They're suggesting it'll flatten out at 5.5 before a rise to about 8 starting at 14:00. Nothing dramatic there, it'll probably change again in 5 to 20 mins time after the rice has started being absorbed, so I'm not paying too much attention to it, but there's enough to suggest watch out for that possible 8 and definitely review it again if a sharp pop up happens around 13:30.
Does it take more of my time? Yes, it does, but after being practically blind on strips for decades, the novelty of actually being able to see this stuff and learning from it hasn't worn off yet.