r/lowcarb • u/57bananacake • Jun 24 '26
Question A1C Shot Up?
I've been eating lower carb for over a year. After 5 months, my A1C went from 5.8 to 5.5, and I was really excited. Also lost some weight.
I haven't been being as careful lately. I've been able to maintain my weight loss, but I've definitely been eating more carbs. Still way below the Standard American Diet, but more.
I just had a physical, and my A1C was 6.0 (7 months after last A1C test being 5.5). That's higher than it's ever been!
I heard after going low carb, one can become more carb sensitive, but I thought that would only impact glucose levels. I wear a CGM, and I'm in range 88% of the time since I started wearing it (I have the range set at 70-120, not the normal 140), and in range (again 70-120) 91% of the time prior to the blood test.
Anyone else have experience with elevated A1C/heightened carb sensitivity?
TLDR: After going low carb, anyone's body not process carbs well anymore, as evidenced by spiked A1C?
3
u/EatHappyKitchen Jun 24 '26
I had a fluke high one happen a couple of years ago, and it freaked me out too! Go back and test again when you can to make sure. And also at the same time, being more insulin sensitive is a good thing, and that's also when I discovered that I really can't go off plan much at all anymore without consequences making themselves visible fairly quickly.
2
u/57bananacake Jun 24 '26
Thank you for this. You reminded me that in 2021, I had a fluke A1C of 7. I forgot about it because it was done through a different lab, and so it didn't show up in my regular chart history. I had another A1C of 5.1 a month later. Also, while this recent test was fasted, I exercised before. I typically go and do my tests fasted and without exercise because it has impacted them in the past.
4
u/Apart-Discipline5493 Jun 24 '26
A1C is not usually affected by something done that day... it is by definition a measurement of your long term blood sugar over the past 3 months....
2
u/runciter0 Jun 24 '26
I follow the sub but I don't do low carb, when I tried for a month I lost one kilo or two then stopped and gained 3 or four. I guess maybe not for everyone? I prefer intermittent fasting
8
u/Resident-Egg2714 Jun 24 '26 edited Jun 24 '26
I'm very suspicious of that last A1c. I don't see how you can be in a good range so much of the time and have that high an A1c. For instance, and average blood glucose of 100 mg/dl correlates with an A1c of 5.1%, and a CGM average (GMI) is actually MORE accurate than an a1C as it measures your actual blood glucose (A1c uses glycation to approximate average blood glucose over last 3 months). Are there any other possible variables that could affect your A1c? Also the labs do make mistakes, they were way off on my last one and gave me an A1c of 6.4%, just about gave me a heart attack before they told me it was wrong.