Laura Schoenfeld: Yes, is the short answer. The longer answer is that I’ve seen a lot of people have fasting blood sugar increase on low carb, and the reason for that is because basically everywhere, except for your brain and your red blood cells, cannot use glucose to function, so you need some glucose for your brain, you need glucose for your red blood cells, and when you’re on a very-low-carb diet, your body basically wants to conserve all that glucose for your brain and your red blood cells. Your other areas of your body things, especially your muscles and some of your other organs, become more insulin resistant to protect that glucose, so a lot of times we’ll see an increase in fasting blood sugar. I see a lot of numbers between, like, 95 and 105 for fasting blood sugar for people that have been on a long-term low-carb diet. And once they start increasing their carb intake, I’ll see that drop to, like, 80 to 90, which is hypothetically better.
Then as far as just day-to-day blood sugar, so if somebody’s been on a very-low-carb diet for a long time and then they have some kind of food that has more carbs in it, because of that systemic insulin resistance, they’re going to have a much stronger blood sugar response to any sort of carbohydrate intake in the short term. They will regain that insulin sensitivity as they start to consistently eat more carbs. Usually there’s a little bit of a sort of scary couple of days, maybe a week or so, that the person is freaking out that their blood sugars are going high after reintroducing carbs, but after some time, the body gets used to it and it gets more physiologically normal as far as their response to carbs is concerned.
This is something that is especially important with any pregnant women that are low carb that are going to be doing the oral glucose tolerance test. Most women on a low-carb diet, if they do that test for gestational diabetes, they’re going to fail it because they’re not going to be able to tolerate that level of carb intake if they’ve been doing low carb for a long time.