Low-Carb Diets and Cycling

[onimity]

Hi Triskieliongirl,

A few responses...

"No one is asking anyone to do anything without the help of a medical professional. With that being said, many medical professionals, my endocrinologist included, appreciate when patients bring them data that can often be more informative than that provided for a lab."

It looked a heck of a lot to me that when Dianyla recommended this to sundial:

"You might want to try your own oral glucose tolerance test that TriskelionGirl told me about a few posts back, and measure your response."

I agree that it can be very useful to test and measure your response to different types of food, especially the sorts you are actually likely to eat, for your own use or your doctor's use. But to do that you need to know how to use a meter properly, how to interpret the results and what sort of tests give you meaningful feedback. You *know* that you have glucose tolerance issues, it is WONDERFUL that you are active and on top of your health, my sister does those sorts of tests/experiments all the time, and they help a lot, but I don't think it is appropriate to recommend homegrown GTTs to someone that doesn't have a known issue/isn't working with an endo. Yes, Dianyla is working with an endo, but is sundial? Self-diagnosis of any condition can be dangerous and misleading IMO. It isn't my intention to be critical of anyone, I realize that we are all here to discuss issues and help one another. I just disagree with the advice I quoted.

"We are not talking about 'a reaction'"

sundial was, it seemed to me. She stated that she is sensitive to refined carbs and that is what I was responding to...

"what is the source of this information...The human body is amazingly adaptable, and can run on many different fuel types."

There are countless studies that recommend rough macronutrient guidelines for people in general, for athletes, and for diabetics. Very few recommend that the majority of calories consumed be from protein and fat. Some do, of course. A lot of type 1.5s seem to have good luck with the Bernstein diet but the 'paleo' diet isn't necessarily good advice for someone that 1) wonders if she's taking in enough carbs 2) has no known BG issues and 3) has said that she tried a low-carb diet for weight loss without much success.

IMO a variety of foods (and I mean real foods here, not different brands of processed/fast foods) is good in that it gives you a variety of nutrients. I assume that you are being very careful about getting your daily requirements but low carb diets can have a detrimental effect on your health if you aren't getting your basic nutritional requirements. You have chosen a specific diet for a specific reason, it works for you and I don't argue with that. However, I would encourage people reading this thread that DO NOT have glucose tolerance issues to investigate other alternatives.

It is true that human body is remarkably adaptable, but that doesn't mean that all means of fueling the body are ideal. Protein does not provide a readily-accessible form of energy like carbohydrates do and that is important to realize if you are exercising regularly.

"Before, even on the bike, I would go through swings of hyperglycemia and hypoglycemia, all the while not being able to access fat stores that was definitely not performance enhancing. That is because when my blood sugar was high, even though I would have insulin turned on, it would be too little to get the glucose into my cells, yet with insulin on glucagon was off and I couldn't get my fat out of storage, so I would be literally starving on the bike, despite having glucose coarsing through my veins and plentiful fat stores. This bugged me for years, because while I understood this, I didn't know what to do about it."

It is kind of hard to tell from the description, but it sounds a lot to me like you are using the insulin that you do produce to maintain your needs apart from food, and compensating for your lack of ability to produce adequate insulin in response to food intake by avoiding carbohydrates. It makes logical sense that this would result in lower BG readings, assuming you still produce adequate insulin to meet your daily needs and that you are taking in enough sources of energy to maintain your needs. Before my sister was diagnosed she lost a ton of weight and we were very worried. Now she thinks that she had issues with her BG in the year leading up to her diagnosis from the feelings she has come to recognize as high blood sugars, ketones, etc. But it was literally as you describe, that she was starving in spite of the food she took in and the fat she'd had previously. Her body just couldn't use it without insulin. If you can get your necessary nutrients, maintain your activity and glycemic control by diet alone, more power to you.

"Anne, I just clicked on your homepage and saw you have first hand experience riding with a type I diabetic. Please get her to read Dr. Bernstein's book. This diet is also advocated for type I diabetics, because by eating lower carb, they won't need as much insulin, and won't experience the kinds of blood sugar fluctuations you described your friend going through, which is better for their long term health."

Sara's my sister (& roommate) & we've both read a lot of Dr. Bernstein's articles but the logic, while it makes some sense, doesn't really work for her. My sister keeps in very good control (her top priority) but doesn't want her life to be dictated by the disease; keeping a well-balanced diet is critical to that. By the same token, neither of us eat a lot of refined anything with the exception of fast-acting carbs for exercise. Our meals tend to have a good balance of protein, fat and complex carbs, she tends to be very good at calculating her boluses and monitoring her BG to determine if she needs to correct in either direction before it becomes a problem. We've both been placed on low-carb diets by well-meaning doctors (I had some episodes of hypoglycemia during a mid-college growth spurt) and the result for both of us was that we were extremely tired, gained weight (in spite of reduced calories), and couldn't maintain our active lifestyles. It didn't work for us, but everyone is different.

Sara always needs some insulin on board or her blood sugars will rise, regardless of whether or not she is eating anything, and this is what has happened in the high blood sugar episodes I wrote about on my blog. She's had a couple of tough episodes lately, all because she was got no insulin overnight. She uses an insulin pump and since she has been cycling a lot has lost most of the body fat on her abdomen and legs and has been having problems with the cannula on her infusion sets getting mangled (she's getting a new type of them though!) Without her basal insulin being delivered (even without eating anything) she can wake up in the 400s. Even a carb-free diet, or total food abstinence won't keep her BG from going sky-high if she doesn't have insulin.

She has virtually no problems in glycemic control related to food intake; her sugars are remarkably stable regardless of what she eats as long as she doses her insulin correctly. Basically, she will take a bolus for whatever she eats, and choose the type of bolus (immediate, or delivered in 30 min increments over a range of time, or a combination of the two).

When Sara is exercising she needs roughly 40g of carbohydrates per hour at a minimum. She doesn't take any extra insulin for these carbs as she would if sitting on the couch, she takes only her basal rates while exercising. Some athletes suspend their pumps while exercising and still consume about the same number of carbs, but that really depends on the person, insulin, and the duration/type of exercise. If she didn't consume those carbs, though, she'd have a serious hypoglycemic episode. Because she is fit, healthy and active she really needs to take very little insulin and has very good carb-insulin ratios. (I should mention too that we're riding ~150 miles a week, a lot of it uphill. We eat a *lot* of food in general.)

"If a diabetic eats a high carb meal and their blood sugar skyrockets, they have to get the insulin dosage just right, or it will first go to high, and can then shoot too low. But, by eating lower carb, the blood sugar won't go up as high, so less insulin will be needed to bring it down, and there is less chance of overeating."

Yes, this is a common problem, but with experience, accurate dosing and devices like an insulin pump (which allows precise dosing of short-acting insulin) it doesn't have to be. It's hard *not* to over-correct for a stubborn high or low, and you are right that it can cause harm but that's one of the realities of taking insulin and something people need to learn to avoid. Sara has actually worked out with the various glucose tabs, gels, honey, bars, etc. that we have for exercise what will hit her when and how hard and depending on her BG and rate of drop will choose the appropriate solution. She tests a lot on the bike and keeps her BG amazingly steady. She usually ends up using glucose tabs to correct a low (because they hit her most quickly and allow for more precision than, say, a Gu) and other foods with slower-acting carbs to maintain her BG through the ride.

"what prevents disease progression is achieving good blood sugar control"

clearly we don't know what prevents the progression of autoimmune diabetes, how that may or may not differ in the various forms it takes, or we'd be able to prevent it. The problem is that we don't know, but there is a lot of interesting research going on in the field at this time. I just brought that study up because there is a lot of interesting stuff going on and I wanted to be sure that you were aware of it, not because I think that it constitutes good advice. I am not an expert, by any means.

As far as type 1/1.5/2/3 I have heard 1.5 sometimes described as the so-called 'type 3,' basically type 1 + type 2. Others say there are only type 1 and type 2 (completely distinct diseases really, with a common symptom) and that type 1.5 is late-onset and generally slow-progressing, though there seems to be a lot of variation. A lot of people also use the terms LADA and MODY... I've read a number of articles/studies and the like because it is a concern for me too as clearly there is a major genetic component which is present in my family. From what I've read there are multiple significant antibodies, especially GAD65, that may or may not be present; the antibodies present can (possibly) indicate the speed at which islet cells are destroyed. But the most common outcome for type 1.5 patients is insulin-dependence, about 80% (of known) cases within 6 years is a stat I've seen frequently but I take that with a huge grain of salt because there are probably many undiagnosed people not figured in, then there are so many mis-diagnoses and people that are diagnosed as adult type 1s because they present full-blown symptoms by the time they seek medical help.

My sister often visits tudiabetes.com, a networking site for people with diabetes & others impacted by the disease. She has learned a lot there and really enjoys being able to bounce ideas off of others that are in the same boat.

The continuous glucose monitoring device is really cool, as long as you have your expectations set accordingly... My sis just tried the Dexcom 7 for several weeks (newly approved by the FDA) and had mixed feelings about it. But yes, you can use it during exercise and while the readings are approximate (it measures glucose in the interstitial fluid rather than in the blood, and as you know even BG readings from the arm and the fingertip can vary significantly) so the Dexcom was sometimes dead on (generally when she was in range) and sometimes 20 points below her BG, sometimes not reporting at all, but it was very good at showing trends. She noticed in particular that the Dexcom was great at predicting lows. You definitely need to use it in conjunction with a BG meter for accuracy/calibration, but it is very useful for watching overnight trends, workday trends, exercise trends, etc., since you can't exactly test 500 times a day. When she went back for her follow-up appointment they looked at all of the results with her over two weeks and it really helped Sara to adjust her overnight basal rates since she was able to see that her glucose readings vary very little but are too high (she worries a lot about hypoglycemia overnight). She had some problems with the transmitter, and the device not receiving data from it so it was kind of hit or miss but very, very useful all in all. She was able to borrow the unit through the Barbara Davis Center for Childhood Diabetes (she's a patient there) and she only had to pay for sensors ($35 each, lasting 7-9 days). She will be getting the sensors that work with her MiniMed/Medtronic pump and those are supposed to be better. Insurance companies are starting to cover these devices, my sister's just got approved. I don't know if you have a major diabetes center near you or not but if so they might be a good place to go to find out about any similar programs. If that doesn't work feel free to PM me and I can see if my sis can find out anything about classes in your area from the Dexcom guy. I've read about the CGMS devices like your endo has too. Of course they don't have the added benefit of showing you (more or less) what is happening as it happens but I've heard they can help a lot in determining the same sorts of patterns that the Dexcom helped Sara with. As long as you kept good track of when you were exercising, etc. that might be a good thing to investigate.

"Please define high-intensity aerobic exercise."

Sorry, I mis-typed there. I meant to say high-intensity exercise, roughly 80% of your max heart rate or greater.

"and sometimes on a ride I'll need to eat a single dried fig every 20-30 miles if my glucose gets too low."

Out of curiosity, have you done experiments with your glucose tolerance while exercising & immediately after? i.e., can you consume more carbs without a BG spike when you are actively exercising? And do you notice a difference based on how complex the carb is and whether you mix it with protein/fat? I would be curious to know as this is definitely what Sara experiences (granted there are huge differences in your situations) but I wonder since people without diabetes also have lower circulating levels of insulin during exercise and active muscles are able to take up glucose from the bloodstream without the involvement of insulin. Without sufficient supplemental carbs you will, at some point, deplete your available glucose and bonk (like anyone) but I wonder if you might extend your endurance/improve your recovery for long rides (if you even need to) by supplementing with carbs during exercise, assuming you don't have BG issues...

I hope you didn't read my posts as critical, I am really impressed by the active role you are taking with your health and the way that you manage it and work with your doctor; that is the way to prevent long-term complications. Living/riding with my sister is very interesting and inspiring to me because there really are so many variables to take into consideration and so many unexpected turns but it is fortunately increasingly more manageable.

Anne