Low blood sugar on low carb diet

I don’t officially have a type yet but it looks like I am a T2 diabetic, currently controlling with diet. My Endo has told me I am confusing, I guess because I don’t fit neatly into one of their categories. I am thin (5’7", 125 lbs), insulin sensitive, and have a family history of adult-onset T1 on both sides around my age (30). But I am negative for ICA and GAD antibodies as well as MODY 1-5. FBG, A1C, c-peptide, and lipids are normal.

I was diagnosed with gestational diabetes in February at 13 weeks pregnant when I failed a 3 GTT (80/216/193/109, A1C-4.8%). After I gave birth my numbers were great for a while and then started creeping back up. I did relax my diet a little, partially to see what my blood sugar would do. Once I saw numbers in the 200s I eliminated carbs again. I also am on a restricted diet for IBS and I am breastfeeding my daughter who has a milk protein intolerance so I am dairy free as well. Basically I only eat meat, certain non-starchy veggies, and small amounts of nuts. I can also choke down an egg about once a week.

I’ve been doing this for a few weeks now and the diet is working well to prevent highs, I’m rarely over 100, but now I am having lows, mostly at night. Generally just in the 60s, but I have woken up as low as 50. I’m not sure why this is happening and how to prevent it. It can’t be reactive hypoglycemia because I’m not going high. I’m not on any meds. The only exercise I do currently is long walks carrying my 4-month old, but I plan to start jogging as soon as I can put her in a jogging stroller.

So, I have some similar experience. I wasn’t “skinny,” but definitely athletic and fit, and have always eaten well. I was diagnosed Type 2 at age 40, and within a couple of months doctors asked questions because of two factors: I was insulin sensitive enough that I would go (true, although not dangerously) low sometimes overnight and almost always during exercise; I didn’t appear to be insulin resistant. Like a lot of Type 2s I was put on a diet and exercise plus Metformin ER regimen, which actually worked really well. A1c dropped precipitously, BGs got to the normal level, and I even lost some weight. Doctors got concerned when I started going regularly low (50s-60s) during exercise and occasionally in the night and morning on a low-carb diet. Also, I have very, very low fasting insulin levels. My last test, two days ago, for example, had fasting insulin below the measurable floor for the test.

So, here’s the deal: my first antibody test came back negative on all counts. My second set of tests had positive results for GAD and IAB, but at low levels. Conclusion: I’m very slow onset LADA, which is consistent with my original diagnosis. It hasn’t changed my daily treatment much at this point. I take Metformin ER to help with Dawn Phenomenon and exercise-highs. I eat relatively low-carb and exercise to help keep my A1c down. I eat carbs when I go low during exercise (under 65 mg/dL) and if I wake up low (under 70 mg/dL). My most recent A1c (two days ago) was 4.8%, which is obviously very good control. I even wake up some days and think “maybe I’m not actually diabetic and it was all just a bad dream.”

So, as for the lows, here is my routine: carry my testing kit on hikes, runs, and bike rides. Test always at 45-60 minutes into intense exercise. Eat a 24g carb Clif-shot (1/2 dextrose and 1/2 starch of some sort) if I’m below 65 mg/dL or feeling dizzy. That’ll bring me reliably back up to about 100 mg/dL, and I will have to eat more carbs than normal later in the day. Just happened to me yesterday, in fact, and I ended up eating 102 g of carbs (including fiber), about 60g “net,” over the coarse of the day in order to stay above 70 mg/dL. The joys of being insulin sensitive and having a pancreas which provides just enough insulin to go low during exercise but not enough insulin to have a normal “phase 1 response” to eating carbs :wink:

That’s interesting that you tested negative for antibodies before testing positive. I wonder if I may still be early enough in the disease progression that I could be LADA and still test negative for antibodies since my FBG and A1c are still good.

It’s nice to see that I’m not the only one who goes low with low carb. Everything I was reading made it seem like it’s not possible to go low on LCHF, so I’ve been feeling like I must be doing it wrong.

I guess I need to add some more carbs back in, I just have to overcome the psychological hurdle. Ever since I was diagnosed I am so afraid to eat any carbs. They feel so forbidden to me and I always feel really guilty when I do eat them. It was something I struggled with a lot during my pregnancy when I couldn’t sustain a very low carb diet.

I have read studies that showed many non-diabetics will often go below 70 mg/dL for up to an hour or more each day, usually in the early morning. Do you have physical symptoms when you fingerstick check and the number is in the 60s? Do you sweat, feel irritable, and confused? Does your appetite spike when you measure these “low” numbers? If your meter shows a number in the 60s and you don’t feel any symptoms then your body could be telling you that, indeed, you are not actually hypoglycemic.

You should also remember that the current fingerstik accuracy is not that great. A measurement in the 60s could easily actually be in the 70s.

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When I wake up in the 60s I just feel hungry and I have a difficult time sleeping. During the day I just feel hungry, a little fuzzy and it’s a little harder to concentrate. I get hypoglycemia symptoms in the 50s though, like I didn’t feel comfortable picking up the baby because I felt I would drop her. I feel shaky, weak, lightheaded, like I’m falling even though I’m laying in bed, kind of nauseous but also like I need to eat everything in the house.

I do know the accuracy of my meter may not be great. When I was in labor the hospital meter kept reading ~60 and mine mostly read ~75.

Commenting on your initial post . . . being at a good weight and very insulin-sensitive is actually a perfectly valid T2 presentation, and not as unusual as your endo believes.

Type 2 is not a diagnosis in the true meaning of the word. It’s a diagnosis of exclusion. When it’s not possible to definitively nail down a specific type diagnosis using available tests, the result is that the patient is classified as Type 2. Type 2, therefore, is actually a catch-all category for diabetes that can’t be precisely classified any other way. Consequently the “Type 2” bucket includes a variety of different presentations. While obesity accompanied by insulin resistance is the most common, it’s certainly not the only one.

For the record, I am type 2 with normal body weight and BMI and no insulin resistance to speak of. (And before people jump in and say, “are you sure you’re really not Type 1?”, yes, I’m quite certain. I have had diabetes since some time in the early 90s, and until fairly recently it was controlled with diet and ever increasing doses of sulfonylureas. If I were truly T1, I’d be dead now.)

So don’t put complete faith in those stereotypes. In any case, the bottom line is that I don’t care whether I am type 1, type 2, or type 37. What matters at the end of the day is good control, whatever that requires. Eyes on the prize!


In my opinion there is almost no such thing as true hypoglycemia without medications inducing it ( or at least it is extremely rare)… unless you just delivered a baby, are bleading out, or other very specific scenario any case of such otherwise is an example of the shortcomings of such definitions and not of an actual physiological state

Breast feeding will affect your blood sugars and other metabolic mechanisms. That’s normal.

You may have earliest stages of diabetes onsetting but unless you’re taking meds for it, hypoglycemia need-not be one of your worries.

Except I havw woken up in the middle of the night with the symptoms of hypoglycemia and blood sugar readings in the 50s so I don’t know how to not worry about it.

Well, I wouldn’t trust my opinion either if I were a stranger on the internet… but for whatever it’s worth I think you will not be harmed by hypoglycemia any time in foreseeable future

I know this seems logical, and I know why it seems important (dangerous lows seem almost impossible without taking exogenous insulin or an insulin-promoter). I mean, the conversation in the “how low have you gone” thread kind of says it all: there are lots of Type 1s on insulin who have experienced BGs down in the teens and twenties, and they’re still here talking about it.

Having just gotten out of a two-hour conversation this morning with my doctors (two of them) very concerned about my regular, “mild” lows (in the 50s and 60s), I take a bit of umbrage at the idea that “it’s no big deal.” Not because I think I’m in danger of keeling over dead from a non-insulin induced low. I don’t think I’m in danger of that. However, there are some serious issues that people have with hypoglycemia that aren’t injecting insulin:

  • chance of getting into a car (or bike) accident go up considerably when you dip into the 50s

  • the “unknown” factor: my GP and metabolic specialist just insisted, less than an hour ago, that I start seeing a real endocrinologist as soon as we can get an appointment, largely because they don’t know what my blood sugars are doing and why they’re doing it

  • even “mild” hypoglycemia is really uncomfortable, and sometimes scary: getting nauseous, lightheaded, blood pressure drops, sweats, waking up, untreatable hunger pangs, etc. on a regular basis is rather annoying at best, and can be debilitating at worst

  • for someone like me, who has “regular” mild lows (50s and 60s) on the order of 4-5 times a week, without exogenous insulin, it’s more than a bit annoying: it seriously impacts my lifestyle

So yeah, I get it. I am not in danger of accidentally killing myself through an insulin reaction. I don’t envy those of you that have that to worry about. But minimizing what other people are going through isn’t the way to make that point. There are degrees to many things in life, and hypoglycemia happens to be one of them. Most of us of any type can remember the horrible feelings after diagnosis and treatment when we first felt “low” at normal BGs. I thought I was going to die. Well, here six months later, when my A1c was 4.8% as of this morning, I get to experience that “I’m going to die” feeling four to five times a week. It has my doctors concerned, it has my wife concerned, and it has me concerned (to an extent).

So hypoglycemia is certainly one of my worries, and it’s quite narrow minded and selfish of you to suggest that it shouldn’t or needn’t be. I know that’s not your intention, but that’s absolutely the way it’s coming across. OP is asking for experience, and you’re suggesting her experience is no big deal. Well, for some of us it’s a deal. I’m sure at some point I’ll look back on my days of mild hypoglycemia inconvenience and laugh at how ridiculous and stupid I was in the early days and years after diagnosis. But for now, it’s a legitimate problem for me. Not the same as your problem, but it’s a legitimate problem for me.


I agree that it looks like I am probably T2, I think my Endo’s hang up is the family history. My father, aunt, and grandfather all developed T1 around my age. I don’t think that necessarily means anything though.

That’s not how I intend to come across and if I was in your or her shoes I’d likely be worried as well. My hope is to reassure her (and you, for that matter) that your worry on this particular matter is not going to result in a major health problem in your life in the immediate future, in my opinion. My hope is that you’d both find relief in that, not entirely understanding why anything else is found…


Oh I know it’s not really serious, my dad is T1, I’ve seen what lows in the 20s look like. I’d still like to figure out a way to fix it if I can. Just like I know 160 is not high for a lot of people but I’d still like to avoid it if I can.

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I know the biochemical reason it happens: at times during my regular week, I have more than sufficient insulin, “normal” BG, and nothing in my stomach. The “more than sufficient” can come from exercise, or it can occasionally (once or twice a month) be completely mysterious where I wake up in the 50s or 60s. What I don’t know is how it fits into the whole being a diabetic thing. That’s what the endocrinologist is for.

And I know you aren’t trying to be dismissive, just wanted to give you a heads up that it can come across that way. I greatly appreciate your comments and even advice, generally speaking! Even mild, clinical hypoglycemia can be a horrible thing to deal with. I wish I wasn’t dealing with it now.

incidentally, my doctors have asked me to do something I find completely bizarre until I can see an endo in January: eat many small meals throughout the day in an effort to maintain a constant BG by always “having something in my stomach.” I really don’t like the idea of eating that way, but I’m willing to give it a try. Something something “euglycemia.”

What evidence there is suggests that heredity can be a factor in some cases of T1. But the link is not as strongly or definitely proven as it is for T2. At least 8 or 10 of the genes that predispose one to T2 have been positively identified.

It is possible that 60 is quite normal for someone not on insulin and hypo inducing meds. I can get that of an afternoon when doing keto. my FBG is 80-100
The 50 is getting low and may be a strip error?

The taked about 70 is a safety margin for those on hypo inducing drugs, so that it is treated before it gets to hypo levels
as always if I feel hypo at any BG level, I should eat something.

It may be the keto diet? have you put your diet through a food counter to see if the percentages of CPF is right and you are getting enough calories…this is what I think is the problem, you may be getting enough protein, but just aren’t eating enough fats to replace the carbs, fats convert 10% to glucose is a steady rate over 8 hours.

but…There are other reasons for a low BG reading besides diabetes meds and RH… It needs checking, A medical hypo for a woman in under 45, so you aren’t at the critical level

also, there is TOFI …thin outside, fat inside. it seems the liver and pancreas fat. is the more important measure. (I don’t agree with a very low calorie diet)

So it looks like I’m eating ~75% fat/20% protein/5% carbs, carbs are only non-starchy veggies and a handful of nuts. 1600-1800 calories.

How would I know if I am TOFI? I’m not insulin resistant, good blood pressure and lipids and my waist:hip ratio is 0.73, but I haven’t been getting enough exercise since the baby was born.other than going on walks for a couple hours most days I haven’t figured out how to fit it in.

If “a lot of people” don’t consider 160 high, I believe these people should pursue further education in the “basics” of diabetes. While 160 may not be rage-bolusing high, it is high…

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While Type 2 may be genetically linked to a greater extent than Type 1, these genetic links do exist. If I were you, I’d be pushing for complete autoantibody testing to rule out Type 1 in light of the fact that 3 other family members were diagnosed with “late-onset” Type 1.

Well I wouldn’t say most of the diabetics I know IRL are well controlled. My dad’s last A1c was 7.4% and he’s definitely not the worst. I still don’t think that just because 50s aren’t dangerously low doesn’t mean it isn’t low enough to want to do something about it.