I really suck at this, could use some tips

I finally got my Dexcom CGM. It works great. Now, though, I’ve come to the part where I need to do the work and figure out how to properly adjust my Tandem pump so I’m not having continual ups and downs.

Meals are where I’m really struggling. I’ve read that you can bolus 20 minutes before you eat and that may help prevent the spikes after eating so I’m going to start trying that. Right now I’m thankful that I can track my blood sugar in real time, but, I’m still struggling with getting the dosage right and its frustrating. I’m a grown adult who’s had Diabetes for 20-some years, I can’t imagine being a kid trying to deal with it, even though I was just a kid when I was first diagnosed.

My insulin to carb ratio is probably still too low, but I’ve raised it a couple of times and it still seems a bit too low, but, I’m not 100 percent. My basal rate seems to be good because throughout the night I’m steady. Just meals are what’s throwing me for a loop. If anyone has any kind of advice for how they figured it out, that’d be great. :slight_smile:

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First off, you don’t suck at this! You are using a CGM, you are asking for help and you seem to have a good handle on what the issues are. So you are way ahead of many out there! Give yourself a big pat on the back!

When my doctor asked me what my biggest frustrations were with my diabetes, post meal spikes was one of them. It is a hard one and takes work. For me, I use Victoza to help with those spikes a little. It also helps with appetite suppression so I don’t eat as much, so less spikes.

Another suggestion on carb ratios, it kinda sucks but you need to be eating the same thing every time you are testing your carb ratio. Using a frozen dinner is easiest because those are all automated on the production line. They do this when I am on a clinical trial and they need the same thing for each overnight testing. This way you can see if that 1:8 is correct or if you need less and 1:10 is better.

The other suggestion and it takes work, is watch your CGM. Most people who have nailed their post meal spikes have their pre bolus timing worked out. For me, 15 minutes works well if my blood sugar is in a good spot. If higher than I should be 20-25 works better. If less, 5-10. But if you have time to spend doing this, you just take your insulin and than sit and watch to see when the first dot heads down. When that first dot drops, is usually a good time to eat. And then see where you are 2-4 hours later.

You also need to have good goals that make sense for you and your medical team. Are you striving for 90% in range or are you good with 70% in range. I have found this is a moving target. For many years, I was good with 70% but with the Tandem Control IQ I strive for 90%. I am not making that goal right now, due to stress from work and COVID but that goal was agreed to be a good one for me and my up to now knowledge of the system. My doctor wou,d probably be ok if I said 70% but we both know, we can do better and for the most part we do. So having realistic goals is a must. Don’t try for it all. Just little baby steps. Pick one thing, figure it out and move on to the next.
I would also suggest some books, Think like a Pancreas, Pumping Insulin and when you what some more advance thinking Sugar Surfing.
Good luck! You’ve got this and keep asking questions!


Thank you Sally. Those are some great recommendations. I’ll look at Victoza.
I can check my breakfasts as I’m usually eating the same thing then. Then the other meals I can probably eat the same thing until I get it figured out.
I do need to remember it takes baby steps. Right now it feels like I’m swinging from high to low and back again, but, I haven’t blacked out or anything, and I’m not stuck at 225 like I was a few weeks ago. So, yeah. It’s a process, definitely! I’ll be bookmarking your post so I can refer back to it later. :slight_smile:

What version of Tandem pump do you have and how are you currently using it? Do you have a t:slim x2 with CIQ (Control IQ)? Are you currently using C-IQ? (Is it turned on? )

Frankly, I am not sure how one calculates either their bolus carb ratio or their basal rates when C-IQ is active. Turning C-IQ on means it will be adjusting your basal rate and potentially also delivering correction boluses. I don’t know how you tease out the effect of a bolus or a basal setting while these are potentially changing at the same time you are testing to validate them. :confused:

You did not ask about another important setting. Some people refer to it as your Insulin Sensitivity Factor (ISF). In Tandem’s pump profile settings this value is referred to as your Correction Factor (CF). It the amount your Blood Glucose (BG) is expected to decrease after bolusing 1 unit of insulin.

For example, if your BG is 180 mg/dl and eventually drops to 145 mg/dl after you bolus 1 unit, then your CF would be 35 (180-145).

If your CF setting is too low then your pump’s correction boluses will be too large and it will drive your BG too low. If the CF is too high then your corrections will be too small.

By the way, have you seen the following pinned forum posts?

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Hi John,
I have a T:Slim x2 with C-IQ turned on. It works great at night time, just meals are where it seems to be not working for me yet. My correction factor I’ve adjusted a little, but I don’t quite know what it is. My CF is too high, but I don’t know by how much. I’m not sure about any of this really, but I’m trying to learn. Thank you, though, I’ll check those out!!

What makes you think your CF is too high? What are you seeing in your CGM results which leads you to suspect this?

When I take the correction as they’re set up, my numbers spike after eating. Yesterday at lunch, I took a food bolus of 5.26 for 56 carbs around noon. By 2:30 I was at 220. For dinner, I took 6 units for 60 carbs. By 10 I was at 300. I also had a few override boluses, too.

I’ve also had a few infusion site issues where I’ve accidentally tugged on the site and I wouldn’t be getting enough insulin because it would be leaking. I’ve found a solution for that, I think, but, my numbers are a little altered by that too.

The Tandem t:slim pump setting which determines how much insulin is delivered for a given amount of carbohydrate in a meal is “Carb Ratio”. If abbreviated it would be CR not CF. The Carb Ratio is also referred to as the I:C ratio or the Insulin:carbohydrate ratio.

The CF or Correction Factor determines how much your BG falls for 1 unit of insulin. This settings determines how much insulin to deliver to reduce a high BG to your target BG setting.

Insulin delivered to cover carbohydrates in a meal is called a meal bolus. The amount of insulin for a food bolus is determined by your Carb Ratio. Insulin delivered to lower a high BG is typically referred to as a correction bolus. The size of a correction bolus is determined by your Correction Factor setting.

What advice has your medical team given you for determining your pump settings?

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Really great summary of the basics in your post, and we’ve seen at least one post recently where it seemed like a relatively new T1 (a year after dx) was put on a pump and told almost nothing about these terms and concepts. I’m wondering if there’s a trend developing with these AID pumps where they think the pump is going to do everything for you so you (and they) don’t need to know anything, just turn it on and let it do the rest. Sure would be a lot easier if that were true. It’s not.

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I’ve had some trouble getting in touch with my endo, but I have an appointment on Friday. Hopefully that will help some. I haven’t spoken with him since I started with the CGM, but yeah, I wasn’t aware of some of how it worked. I’ve tried to ask questions and learn more about it, but a lot of it is still relatively new to me. Part of the issue si that there’s been several balls in the air at the same time. I’ve got how many carbs I’m eating, what my meal correction is, what my CF is, what my basal is, whether or not the injection site is properly working, and all of that can affect what my numbers look like and trying to adjust them all at once is a bit overwhelming at times. But, one small step at a time I guess!

Diabetes is 24/7, doctor assistance happens much less often. The solution? You need to steadily build a foundation of knowledge that will make needed consultation with your doctor a rarity.

We still need doctors but for moment to moment assistance you’re much better off depending on yourself. This competence cannot happen overnight but I would recommend the books that @Sally7 listed above plus Dr. Bernstein’s Diabetes Solution and Adam Brown’s Bright Spots and Landmines.

Your personal diabetes knowledge is the human software that runs your glucose metabolism on manual. This is no small task! Invest in yourself and chip away at the list of many fine books on this topic. It will take time but if you prioritize it, after five years you will be the metabolic expert on you. No doctor will ever know your glucose metabolism that well.


Well, I ordered all those books! I’ll be reading them when they arrive! Thank you.

I’ve heard from other people who have had T1 for years and only recently got a CGM, whose initial response was along the lines of “OMG, I had no idea this was going on!” When you go from finger sticks 5x/day or so, little snapshots, and then suddenly see the whole movie it can be quite gobsmacking. Suddenly you see what was going on “in the dark” between finger sticks, and it’s like turning the lights on in your kitchen at 3am and seeing cockroaches scrabbling for the corners. I’ve coined the term “CGM Shock” for it. And then it’s “What do I DO about this!?!”

Pre-bolusing is one thing. Always surprised that Dr’s prescribing CGMs for people don’t seem to know about that. Probably its single most useful application for most of us. Another is, yeah, some of the newer oral meds developed for T2 that can actually be very beneficial for T1. I haven’t tried Victosa, but I can emphatically endorse Jardiance for flattening out your curves. My endo started me on it about 2yrs ago, and it has been spectacular. I credit it with getting me to a sub-6 AIC for the first time since I was dx’d in 1983. It’s off-label for T1 but I think most endos are willing to try patients out on it on a case-by-case basis. Worth asking.

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Remember that if you have turned the pump’s C-IQ feature on, then the pump is attempting to deliver additional insulin by increasing your basal rate when you BG is above your target BG setting. This is also a piece of the puzzle to consider.

Did you get any pump and/or CGM training from your endo’s staff? How about pump training from Tandem? Your endo’s staff should have placed you in contact with a trainer from Tandem.

Have you been uploading your pump’s data to Tandem’s t:connect database? When you do that, you can also sign in to Tandem’s t:connect database portal to review the data uploaded from your pump about CGM results and insulin bolus & basal delivery.

I’ve had a little bit of pump training on how to work everything. I’m all signed up in the Tandem database. I’ve talked with the trainer a little bit, but she’s helped me with some of the basic things. Haven’t gone over much into how to correct my insulin settings, other than to say that the doctor typically is the one to do that and she couldn’t make any recommendations. I’ll get some of these books read and figure out how to better fine tune it myself if I have to, and then the doc can help when he’s able, I guess.

For whatever it’s worth, the Tandem trainer I was in touch with wanted me to review the ebook (PDF) at the link below before doing a training session. It looks like a (possibly too simple) overview of pump training. But maybe it might help put some things into context for you.

Guide to Successful Pumping (Tandem’s pump workbook)


Please talk in depth to your endocrinologist. He will need your blood glucose values from at least the last 2 weeks. Upload on T :Connect if possible. You can print the log book and other reports for your doctor to review. There are formulas that your doctor should know in order to set your insulin to carb ratios and correction factors, and basal rates. These settings may vary from meal to meal and time of day. I have 6 different settings in my profile. I need more insulin at breakfast than dinner for example. My basal rate varies throughout the day. I hope this helps. Jane Gwinn


You have gotten so excellent tips from a number of regular contributors here. I’d like to toss out a few minor, additional thoughts:

  1. Does your endo work with one or more CDEs (Certified Diabetes Educator)? And would your insurance cover appointments with a CDE? A good CDE often has more time to spend with you and often has more hands on experience with a pump and CGM than an endo. If you can find a CDE that is either T1D themselves or has a kid/spouse/sibling that is, you can often learn a lot because they understand the 24x7 nature. While you might think that would be hard to find out, your endo will know …

  2. Setting basal rates, IC ratios, and correction factors is tricky … both because all those values probably vary over 24 hours and because even if you try to run the same experiment 10 different times, at some level you are going to see 10 different results. I was lucky in that I began using a pump 1-2 years before Basal-IQ and then Comtrol-IQ became available. That forced me to try to determine basal rates, IC ratios and correction factors at different times of the day. For me, at least, my basal rates are lowest at night and my IC ratio is the highest then. If I used those values around the clock, I would definitely see big postprandial spikes. Everyone is different, but I think that an argument can be made for turning OFF Control IQ from time to time to check your settings a different times of the day. I think that it was @DrBB who commented that this first generation of closed loop isn’t yet good enough to just let it run. While I expect that we will all see more capable closed loop systems over the coming years, we are still at a point where our settings DO play a significant role.

  3. Finally, meals with lots of simple carbs are hard to make spike-free … at least I can’t avoid that. With CGM, in particular, it makes it easier to also test food and dietary choices. Maybe something with lower total carbs, more complex carbs, or even more fat can more easily flatten a peak than a big slug of insulin.

Best of luck. You are working with some pretty amazing tools … but it does take time and effort to master them. (Actually, I’ve never “mastered” anything associated with T1D … but I am still getting better at using the tools that I have at my disposal.)

Stay safe!


I believe this illustrates the single most important point to implementing effective ongoing treatment. Diabetes doesn’t stand still, neither should we. If you can learn how to detect when changes are needed and how to do the personal experiments that will inform your tactics, that is the key.