Does Low Carb eating increase carb sensitivity?

Some people claim that when they adopted a low-carb diet they became more sensitive to carbs. What do you think? Is it the low-carb eating, or is it the progression of the disease? Hey, I thought that carb-sensitivity is what diabetes is all about!

When you adopt the low carb lifestyle, your insulin requirements naturally settle to an amount that covers the few carbs that you do eat. If you all of a sudden add several slices of pizza, you are going to need a mega bolus and probably some extra basal for a day or two to cover it. You won’t have had enough insulin on board from the low carb eating to cover the carbs associated with that kind of meal. I believe it’s a simple case of insulin supply and demand. That’s been my experience with it.

I agree with Cinderfella. If I attempt to increase my carb consumption (with non veggie type food) I notice that even if I calculate/guess accurately and my 3 hour post meal number is within range, 2 hours later I am sky high. It is just further proof to me that my body has adjusted to the low carb diet and when I deviate, it doesn't respond well.

That's not exactly how I understood Cinderfella. I think he's saying that because we are low carb, and do not take a lot of insulin, our body does not have the insulin to deal with a large amount of sugar. I guess maybe there is some sort of longer-term effect of the insulin we take - both the basal and the bolus? (That's why they say when you are trying to adjust the basal insulin, wait 3 days to see how your adjustment worked).

No No's just supply and demand... A small dose of insulin is adsorbed into the system faster than a mega dose, it's more efficient, it's duration is shorter, and there is less error.

On the carb side a small dose is easy to process, and a massive dose overwhelms the system. The body quickly uses up small amounts of carbs and sugar, but if it's swamped with mass amounts everyday, then the body cannot use it and we cannot handle excess sugar, we have to use it, store it, or pee it out.

It's supply and demand. Pure and simple. When they adopted a low carb diet they started counting their carb intake more carefully.

Well, we do become carb intolerant on a low carb diet. I am sure part of it is related to adjustments our bodies make in digestion. In fact, you are advised to "carb up" in the days leading up to an Oral Glucose Tolerance Test. Here is what LabCorp advises:

Patient should be active and eat a regular diet that includes at least 150 grams of carbohydrate daily for three days prior to the test. The patient should be instructed not to eat or drink anything except water for at least eight hours and not more than 14 hours before the test. Patients should also be advised to discontinue, whenever possible, all nonessential medication that can affect glucose metabolism at least three days before testing.

Yeah, if you low carb to the extent that you become "fat-adapted", it does change your physiology to favor fat-oxidation and gluconeogenesis of protein to glucose over the use of dietary sources of carbs.

This makes complete sense and is not a bad thing if you stick to your low-carb diet.

Another factor: When you go low carb your basal/bolus ratio shifts rather sharply and unless you are counting total available glucose there is a good chance that your daytime basal may be covering a bit of your meals. If you go back to a medium carb meal, the ratio won't work because your basal won't be sufficient to cover.

I'm always a little confused as to the number of total (not net) daily carbs constitute a low carb diet. And what TDD would be considered low for Type 1 and Type 2? I know everyone is different, but is there a good guideline?

Good question, Kim! We debate the definition of low carb a lot. But here is my take on it: True "Low Carb" with capital letters is Bernstein Low Carb which is 30 a day. But people often use it to mean anything say under 100. To me under 100 is "moderate low carb".

The second is harder because we are all different. Basically whatever insulin dose works for a person is the right dose whether it's teeny or humongous! But for a Type 1 I would say anything under 15TDD is pretty low, though certainly not rare, especially if the person is low carb. I have no idea for Type 2, but I know if someone who has been diagnosed Type 2 posts that they are taking say 25 units a day, I might suggest they get tested to see if they are, in fact, Type 1.

Yeah, not sure what constitutes low carb but Zoe's explanation is reasonable. More specifically, if you want to be "ketogenic", there is an absolute minimum number of daily carbs that will get you fat adapted. Bernstein's guideline of 60 g/day will probably get you there.

As far as a guideline for TDD of insulin, a good way to look at insulin dosing is to determine your "mass specific" TDD by dividing your insulin dose by your weight in kilograms. I've seen references that say diabetics typically fall between .4 Units/kg and .8 Units/kg. Low carbers typcally fall on the lower end of that range.

As always, YMMV.

When you say "more carb sensitive" do you mean that we need more insulin to cover a gram of carb? I have not found that to be true, but I am always surprised when I get serious about my diet how much insulin I need just to cover protein. When I'm eating SAD level carbs, its like the protein is practically a free food bc its overwhelmed by the carb.

So I can imagine someone thinking "my meal only has X grams of carb but I still have to do all this insulin" not realizing that the insulin is necessary to cover the big whopping steak sitting next to the 2 grams of carb worth of spinach next to it.

And I think if anything, I become more sensitive to insulin while eating LC, which I think must be the opposite of being more sensitive to carbs.

I thought when people wrote that they became more 'carb sensitive' that their BG goes up more than it used to, when eating carbs. (I guess the way you put it is really the same - "need more insulin to cover a gram of carb").

Are you saying that you now need MORE insulin to cover the protein part of the meal, or that it strikes you suddenly that you ALSO need insulin even if its just protein?

Insulin sensitivity and carb sensitivity are not necessarily the same thing and are related only in the context of having to cover your carbs with insulin and lowering BG levels.

Insulin is actually a very powerful hormone that does a whole bunch of other things besides play a role in BG maintenance. Off the top of my head, it's essential for fat storage, glycogen storage, and building amino acids into proteins.

I can see being on a low carb diet may increasing insulin sensitivity because having insulin on board actually inhibits fat oxidation for energy, protein usage for energy, and the gluconeogenesis from protein to glucose. All of those processes are very important for extremely low carb diets to work. All those metabolic processes have to be upregulated to maintain energy and BG levels in the absence of dietary carbs and if you're shooting up with lower amounts of insulin, you're helping those processes.

At the same time, if you decide to take a big carb load while on an LC diet, you'll probably see a bigger spike because the metabolic pathways to use dietary carbs that have absolutely nothing to do with insulin use have been downregulated.