Reactive hypoglycemia before diagnosis?

Hi everyone - I’m 28f with BMI 19.8. I’ve read through so many posts on this forum that have been very informative but I wanted to share what I’m going through to see if anyone has had a similar experience.

I’ve been dealing with what I thought was low blood sugar for about 9 years now but it’s gotten worse recently so I finally went to a doctor about it and was officially diagnosed with reactive hypoglycemia. If I don’t eat for awhile after eating a lot of carbs (especially pure sugar, like candy), I will drop to the 50s around 3-4 hours later and feel terrible. She prescribed me a CGM to keep an eye on it but I’ve found it pretty easy to manage as long as I eat every 2-3 hours.

This is my first time really following my blood glucose numbers and I’m having a hard time knowing if mine are typical or not (it’s really hard to find consistent info about healthy glucose levels in non diabetics). I regularly see numbers anywhere from 150-190ish (highest was 208) on my CGM after I eat anything with more than 40~ carbs.

The majority of the time it’s under 140 at two hours though, with a few exceptions. I had a bagel once and was at 149 at two hours, and the other night I had crackers before going to bed and I got to 161 at one hour, 116 at two hours, but after I went to sleep (around 3 hours after eating) it went back up to the 160s and stayed there for an hour before coming back down to the 80s. Occasionally it’ll be above 140 until around 100 minutes after eating and then it starts to drop.

It’s all so inconsistent and confusing so it’s hard to determine any sort of pattern. One day I’ll only get to 135 after a meal but then when I eat the same thing 2 days later it’ll be over 170.

My question is - did anyone else experience reactive hypoglycemia and/or something similar to this before being diagnosed with diabetes? Is this something that’s seen before both Type 1 and 2? I don’t have any family history of diabetes or any other immune conditions although I have a very mild autoimmune condition myself as well as several allergies. I’m very active and at a healthy weight.

I know of course that the best thing would be to bring this up to my doctor but I’m pretty sure they’ll tell me that I don’t have anything to worry about, which is probably true, so I wanted to ask people who may have been through this.

Thanks in advance!

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Hi from someone who experienced reactive hypoglycemia from childhood. I thought it was normal hunger and didn’t realize it was hypoglycemia until I was diagnosed as type 2 and given tools and classes.

For the years before I would self treat with a Coke and/or candy bar. I know now this was the absolute worst thing to do.

Worse I have a friend who was diagnosed with reactive hypoglycemia and I gave him good dietary advice while not recognizing I was RH as well.

We don’t handle carbs well. Our blood glucose levels will spike high with accompanying high insulin which causes a drop. This yo-yoing of BG is very unhealthy.

I was diagnosed with Type 1 (a fast onset) at age 24. As I experienced lows with diabetes, it made me remember how awful I frequently felt in the late afternoon back in high school. Shaky, sweats, severe hunger, etc. So my guess is that I had hypoglycemia for many years before my diabetes diagnosis.

I think the post meal numbers you are seeing are abnormal and indicative of diabetes. But it may be a very slow onset with no particular treatment required yet. But I would try to get a referral to an endocrinologist and have an expert evaluate your situation.


At age 30 I was diagnosed with T1D that was slow onset. I actually had several symptoms up to a year earlier. I distinctly remember more than one episode of reactive hypoglycemia that was cured by a candy bar. These episodes often occurred a few hours after a bowl of breakfast cereal in the morning.

Your numbers seem high to me and their inconsistency can be explained by an inconsistent insulin release. If I were you, I would wear a continuous glucose monitor, in an effort to learn more. A low carbohydrate diet may help.

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Thanks for your response! I’ve been wearing a CGM for the past 8 weeks or so which is where I’m getting these numbers from. I’m having a hard time discerning any pattern from it though - my numbers will be “normal” for a few days and then all over the place for the next few. Very confusing.

Yes, I overlooked your wearing of a CGM in your already posted action. I think your metabolism is erratic and that is consistent with many reports of people whose pancreases ultimately failed.

Getting an expert to agree, like an endocrinologist, is unfortunately not an automatic thing. You may be working with an enlightened one, however, since you needed the cooperation of a doctor to get an Rx for a CGM.

Hi, this is exactly what I experienced. I had my GAD-Antibodies checked with UCSF, which is when they enrolled me in a Trial Net study and told me I was in the very early stages of type 1.
Basically they told me I was “pre diabetes” with type 1 so I wear a dexcom and monitor carbs while waiting for my beta cells to give up to finally go on insulin. My endocrinologists told me to wear a medical ID that says type one on it too. Apparently I’m one of the few (and growing) that has gotten a diagnosis before needing insulin and going into DKA. They say with the TrialNet testing and research they’re doing it’s getting more common to see “dysglycemia” before a diagnosis of type one because they’re catching it earlier than when someone comes into the ER with DKA.

All the tests I’ve done-
-hypoglycemia gene panel
-complete islet AB screen
-CBC with differential
-Whole exome sequencing
-Thyroidglobulion antibodies
-Thyroperoxidase antibodies

Other information:
-I’m 22, male, 5’8” and 160 pounds. I was adopted and have no knowledge of family history. I play baseball, wakeboard, hike and bike often. I have a endocrinologist, diabetes educator, and diabetes dietitian who all follow my care. I think I got lucky because I was still with my pediatrician so they fast tracked me into the pediatric UCSF endocrinologist to do testing.
To try and answer your question of healthy blood sugar levels, I’ve been told my multiple doctors ““Healthy” blood sugar levels are considered 80-120 fasting and less than 140 two hours after eating”.

Currently my “treatment” is wearing a dexcom, counting carbs (not restricting, I’m supposed to be getting at minimum 45 carbs a meal [preferably whole grain] and 20 carbs a snack [WG preferred]. I was losing way too much weight restricting carbs), making a point to seek out whole grain carbs over white carbs (but not always, I still eat white bread and crackers and stuff), pairing fat, fiber, protein and carb especially when before I exercise (think avocado toast with bacon or an egg on whole wheat sourdough), drinking watered down Gatorade while heavy or extended exercise or when I’m out in the sun all day to help refill my glycogen stores in my muscles. I treat lows starting with 8g carbs with a BG under 75 and 15g under 55, followed by a protein.

My doctor wrote me a letter for school(college) that tells them I’m seeing UCSF for diabetes management and I need to have access to treatment and dexcom.


Wow this is really cool that you have such a grip on the ups and downs of very early diabetes and what seems to work for you. Maybe some of the other people here who have reactive hypoglycemia will be able to make use of your experience. I wish more Dr.s would be willing to run these simple tests when their patients start complaining of BG issues. It could give the medical and patient community so much insight.

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I am a 72 yo with type1 for 49 years. Two or three years before I was diagnosed and was in college I would eat the breakfast buffet and about two hours later would get severe hypoglycemia with sweating and shaking. Never saw a doctor for this but was absolutely certain it was hypoglycemia and there was no glucose home testing in 1971 much less a CGM. Three years later I develop classic type 1 with weight loss etc. ( my c peptides have always been near zero). I have researched this is literature and have asked my endo and no one has heard about reactive hypoglycemia as a precursor of type 1 diabetes. I have also blogged about it and you are the first one to bring up this subject. From what you say, you have some mild glucose intolerance and sometimes this can progress into type 2 diabetes but the hypoglycemia part is very interesting and you are doing the right thing by following your blood sugars. Reducing carbs will probably reduce the low sugars

Yea, I was diagnosed on 3/29/22. So hopefully it will start becoming standard to run these tests soon.

I also had reactive hypos before diagnosis.
It was a time I was working at night and my schedule was all mixed up. I was playing volleyball in a community center, often I would skip breakfast and play a few hours.

A few times my legs went wobbly like I couldn’t control them and I would sit out but it heat coming back. Some how I knew I needed to eat so I would grab a candy bar and a coke and I felt better. It was a month before I started having obvious diabetes symptoms. Which came on very fast ended with dka.
I wish I had known what to look for.
I was 21 and pretty much didn’t see doctors because I didn’t need to


@TDThrow20 ,
Most definitely. I had two extreme hypos as a child. both after eating a lot of sweets with no real food on a very hot day (though I don’t know if the heat is really relevant), and after some vague but unpleasant complaints (and some blood tests) when I got to college I was diagnosed as having reactive hypoglycemia.

I was correctly diagnosed as a Type 2 in late middle age.

I read somewhere that this is all typical of metabolic syndrome, but I don’t feel like hunting the source right now. Maybe later. I’ve got a few other things too, and both my endo and my GP agree that I do have metabolic syndrome.

Two of my kids had some serious hypos under the same circumstances. They are now 30-ish.

I have warned all of my kids many times.

Good luck, and welcome,

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Yes! I was diagnosed at 29 with type 1, but I remember on many many occasions where I has low sugar symptoms. To the point where my diabetic grandpa tested my bloods when I was about 15 and I was 54. Anytime I would eat something very sugary this would happen.