Low-Carb Diets and Cycling

[Dianyla]

Popping in for a quick update.

Well, this morning I finally got the chance to do my at-home glucose challenge test. The weapon of choice in this case was some yummy peach-ginger sorbet from a local gelatto place here in Portland. I'm approximating that the 1.5 cups of it that I wolfed down contained about 80 g of sugar (mostly fructose, though molecularly fructose is just one step away from glucose so I figured it was close enough).

What I got was this:
t=0 88 mg/dl (fasting 12 hours overnight, immediately before eating)
t=15 111 mg/dl
t=30 155 mg/dl
t=45 124 mg/dl
t=60 119 mg/dl
t=75 95 mg/dl
t=90 111 mg/dl
t=135 94 mg/dl

So, based on this, I think that my insulin response is working alright. But my fasting glucose is still generally high (90's or low 100's). Triskeliongirl - I was doing more reading about Dr. Bernstein's stuff and I've got his book on order.

[sundial]

I've been following this thread with interest and I have a couple of questions. First, my weight has remained unchanged and my clothes aren't any loser--even though I'm cycling more. Could the gels be the culprit?

I usually start reaching for a Carb-boom or honey about 45 minutes into my 2 hour ride. My pre-ride meal is 1/2 c oatmeal, coffee and water, or a banana with coffee, or lately, a slice of low calorie wheat bread with a tbs. natural pb with tbs. raw honey. I used to drink Gatorade on my ride, but I've since ditched that for the sport beans on a really hot day. I carry more water now than anything else.

My post-ride drink is a Boost with 240 calories and 33 g carbs.

I've noticed after I take in carbs, I feel sluggish and sleepy, but I'm afraid if I don't take in enough post-ride, I'll never catch up and end up feeling beat with dead legs. My appetite is suppressed and I don't eat big meals, so I'm wondering why I'm having to work really hard to get just a little weight off. (My blood levels are within normal range for thyroid and glucose.)

When I did Atkins, my weight barely came off. I felt good and I knew my glucose levels were stable, but I didn't have endurance for the eliptical trainer at the gym. In fact, I felt weak and I just didn't have enough steam when I worked out for 45 minutes or so. So I'm a little leery of doing a low carb diet again only because I don't want to become frustrated with poor performance on my long ride.

Any suggestions for me?

[Dianyla]

My appetite is suppressed and I don't eat big meals, so I'm wondering why I'm having to work really hard to get just a little weight off. (My blood levels are within normal range for thyroid and glucose.)

Define "normal range"? I tested as "normal" for years. It all depends on what exactly is being tested and what reference range they are using to interpret the results.

So I'm a little leery of doing a low carb diet again only because I don't want to become frustrated with poor performance on my long ride.

If you have had good results with low carb in the past, you might want to check out the Paleo Diet for Athletes. I'm still in the middle of reading it, but the gist so far is that you can judiciously use carbs in certain ways before, during, and after exercise. The rest of the time, you do a regular paleo diet consisting of lean meats, vegetables, and fruits (no grains, legumes, dairy, or refined crap).

[sundial]

Dianyla, my fasting glucose levels were under 100. My throid profile (T3,T4, TSH) was normal as well. That being said, I know I'm sensitive to carbs and I get really sleepy after eating some carbs UNLESS I eat a good protein source first.

I'm content eating tuna or salmon for lunch along with a green salad with blue cheese dressing. For dessert I like to eat a bowl of frozen blueberries with a little frozen cool whip. I feel pretty good after eating that. I don't feel good after eating anything white--bread, sugar, potatoes, pasta, white sauces, flour, etc. So I snack on almonds and macadamia nuts, cheese, natural peanut butter and occasionally an apple. Most fruits really bother me and I avoid them. I also noticed I am sensitive to tomatoes and tomato products.

Just curious, how much carbs should I take in for a 3 hour ride? Yesterday I ate 1/4 c of egg whites with one slice of low calorie wheat toast. It helped fuel me for the first 2 hours, but I started to take in a little honey 45 minutes into my ride, and the last hour I had a Carb-boom. Was that adequate? I felt like I needed just a little more, but I didn't have any on me. When I finished my ride, I ate a Cliff bar on the way home. Then I watched my carbs the rest of the day. Is this kinda what is recommended?

[onimity]

Hi sundial,

Carb intake requirements of course vary from person to person, but this thread:
http://forums.teamestrogen.com/showthread.php?t=17730
had some good numbers.

When you say you are sensitive to carbs, do you notice a difference between complex and simple carbs? I can be sensitive to simple carbs when I'm not exercising if I don't eat anything with fat/protien with them. Well into a ride, though, all I want is carbs. If you find that carbs are knocking you out on the bike you might want to mix simple carbs with something more complex (as long as it doesn't upset your stomach). But your body needs energy during the ride.

My favorite pre-ride snack is a big glass of milk. Sometimes 2% chocolate, but my favorite is whole milk. It's my favorite recovery drink too, usually chocolate then though. I wonder if you aren't getting enough carbs after your ride. After a long ride I am *hungry* for carbs. I regularly eat everything in the house after a long ride and if I don't I feel sluggish the next day. I don't know about the Boost, I assume from the calories that it has protein too? You might just try milk and then a complex carb after that, with some protein. Pasta, potatoes, etc. with meat/seafood. If white bread etc. bothers you, stick to whole grains or small portions. Maybe a couple of fingerling potatoes, for example, rather than a huge russet. Or beans, lentils, rice... there are lots of delicious options.

You might just try calculating the number of calories you are consuming and burning over the course of a week and make sure that you are in (and not below) your weight loss zone and that you are approximating your recommended carb intake while cycling.

Anne

[Triskeliongirl]

Hi Dianyla- If you really did the test with fructose and not glucose, it is not a glucose tolerance test. It only tells you how your body processes fructose. Here is an abstract indicating that even diabetic patients can handle fructose better than glucose:

1: Diabetes Care. 1980 Sep-Oct;3(5):575-82.Links
Effects of oral fructose in normal, diabetic, and impaired glucose tolerance subjects.Crapo PA, Kolterman OG, Olefsky JM.
We studied the acute effects of oral ingestion of 50-g loads of dextrose, sucrose, and fructose on post-prandial serum glucose, insulin, and plasma glucagon responses in 9 normal subjects, 10 subjects with impaired glucose tolerance, and 17 non-insulin-dependent diabetic subjects. The response to each carbohydrate was quantified when the respective carbohydrate was given alone in a drink or when given in combination with protein and fat in a test meal. The data demonstrate that (1) fructose ingestion resulted in significantly lower serum glucose and insulin responses than did sucrose or dextrose ingestion in all study groups, either when given alone or in the test meal; (2) although fructose ingestion always led to the least glycemic response compared with the other hexoses, the serum glucose response to fructose was increased the more glucose intolerant the subject; (3) urinary glucose excretion during the 3 h after carbohydrate ingestion was greatest after dextrose and least after fructose in all groups. In conclusion, fructose ingestion results in markedly lower serum glucose and insulin responses and less glycosuria than either dextrose or sucrose, both when given alone or as a constituent in a test meal. However, as glucose tolerance worsens, an increasingly greater glycemic response to fructose is seen.

PMID: 7002511 [PubMed - indexed for MEDLINE]

[Dianyla]

Hi Dianyla- If you really did the test with fructose and not glucose, it is not a glucose tolerance test. It only tells you how your body processes fructose. Here is an abstract indicating that even diabetic patients can handle fructose better than glucose:

Hey, good catch! I ate a tub of artisan sorbet locally made. It didn't have a nutrition info label, but I am guessing it was mostly fructose (from the fruit) and maybe some sucrose (from cane sugar) as well. I assumed it would be processed roughly the same as glucose, being all simple sugars. I guess it's good news for eating healthy sources of carbs like fruit. I'll redo the test with straight glucose, then.

This week I saw my doctor and based on what I was telling him he ordered some sort of diabetic panel. I know it contained the hbA1C, serum insulin, and one or two other tests. Also a lipid panel. So... I'm really interested in the A1C results since that will show a better picture. I'll know more in two weeks when I go back to discuss results.

[Dianyla]

Dianyla, my fasting glucose levels were under 100. My throid profile (T3,T4, TSH) was normal as well. That being said, I know I'm sensitive to carbs and I get really sleepy after eating some carbs UNLESS I eat a good protein source first.

When they tested your T3/T4, did they test total values or free values? My scenario is that my TSH is within the normal range (though, just barely) and testing Total T4 and Total T3 didn't show my problem, since I have normal amounts of these hormones. The problem is, most of my T4/T3 is in the less available storage form, not the active usable form. The Free T4 or Free T3 tests actually indicate how much active and bioavailable thyroid hormones you have in your body, as opposed to the total. Also, there is a Sensitive TSH (sometimes called STSH) test that is more accurate.

I found my local doctor from this online list:
http://www.thyroid-info.com/topdrs/index.htm

So, back to the carbs. It is possible to have a normal fasting sugar level but have really bad response to glucose. 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 also noticed I am sensitive to tomatoes and tomato products.

You might have a problem with the Nightshade family, which contains potatoes, tomatoes, eggplant, sweet peppers, chili peppers, and tobacco.

Just curious, how much carbs should I take in for a 3 hour ride? Yesterday I ate 1/4 c of egg whites with one slice of low calorie wheat toast. It helped fuel me for the first 2 hours, but I started to take in a little honey 45 minutes into my ride, and the last hour I had a Carb-boom. Was that adequate? I felt like I needed just a little more, but I didn't have any on me. When I finished my ride, I ate a Cliff bar on the way home. Then I watched my carbs the rest of the day. Is this kinda what is recommended?

What you just described sounds pretty good, at a glance. There are some formulas in the Paleo Book that talked more specifically about how many grams of carbs and protein you should use for x pounds of body weight and y minutes of intensity. I can go look those up tonight, if you like. But, formulas aside, what matters is that you feel that you are consuming enough to have good energy but not so much that you start having a bad reaction. You may just have to go by feel or start measuring your own glucose to know what feels normal for you.

[onimity]

Please, ladies, if you are worried about your ability to process glucose have a glucose tolerance test done by a medical professional who has accurate equipment and the expertise to interpret the results. There are so many variables, meter accuracy, digestion, etc. etc. etc.

I don't know *anyone* that doesn't have a reaction to a lot of refined carbs and it isn't necessarily an indication of a glucose tolerance problem; The sugar crash will happen to most people as we have evolved to eat a wide variety of foods over a very long time and refined sugars are a very recent addition to that mix. I can feel absolutely exhausted after too much refined sugar and have a BG reading of 90 mg/dl...

But low-carb diets are not an ideal solution, especially for an active person.

According to the numbers zen posted (which are geared to rides > 4 hours but seem similar to rates I've seen for endurance activity in general) I, at 130 lbs, need 41.3 g of carbs per hour of riding. That seems about right to me, a gel/honey(or carb equivalent) and diluted sports drink an hour works well for me. Sundial, in what you posted I see 27g from the carboom and ??? from the honey (a honey stinger packet has 29g), so for me that would be too little. Sounds like your body told you the same thing.

Then, after exercise, zen's numbers give me 70-88.5 g of carbs *an hour* (with protein) for 4-5 hours following endurance exercise. Again, that's for a longer ride but reflects my needs pretty accurately after a 60+ mile ride.

If you aren't getting the energy you need your body will panic and 1) have less energy when you ride and 2) have a hard time losing weight because your body will horde any energy you give it.

my two cents...

Anne

[Triskeliongirl]

Anne, I have to take exception with a few of your remarks.

1. "Please, ladies, if you are worried about your ability to process glucose have a glucose tolerance test done by a medical professional who has accurate equipment and the expertise to interpret the results. There are so many variables, meter accuracy, digestion, etc. etc. etc. "

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 was my doctor that asked me to do the eat the pancakes glucose tolerance test and email him the results. He said it was very hard to get a lab to follow you beyond 2 hours, and especially beyond 4 hours, and to take accurate time points. He also said he would rather know how a body responds to a real meal, since that is what we are going to eat, vs glucola syrup. Dr. Bernstein also, suggests that one keep detailed records of food intake and post-prandial blood glucose readings that you bring with you to your doctors visits. Of course all these recommendations assumes that one buys an accurate meter, but accurate meetings are out there, and that a person is trained in how to make and record the measurements, but that information is out there too (very detailed in Dr. Bernstein's book). In fact, my doctor tried to order a test to measure my insulin and glucose response to a high carb meal, but my insurance company refused to pay for it. However, they were happy to pay for single glucose, pepC, and insulin measurements. So, he wrote 2 lab slips and had me take them to the lab with instructions to have the first test done (I was still fasting), then to go to a diner and eat 3 pancakes with syrup, and to return to the lab and ask them to process the second set of tests 2 hours after the first bite of food. I then continued to take more frequent glucose measurements over 6 hours, and he put my data together with the lab's glucose, insulin, and pepC results to determine that my body does not make enough insulin. He could also tell from the ratio of insulin to glucose that my problem is not a lack of sensitivity to insulin, but that there is simply not enough insulin to clear the glucose at the correct rate.

So, all I was suggesting was that while Dianyla was waiting for her doc's appt., she take these measurements and bring them to her visit to have a more productive visit. It sounds like that happened since he ordered a diabetic panel that my have been delayed without the information she provided.

2. "I don't know *anyone* that doesn't have a reaction to a lot of refined carbs and it isn't necessarily an indication of a glucose tolerance problem; The sugar crash will happen to most people as we have evolved to eat a wide variety of foods over a very long time and refined sugars are a very recent addition to that mix. I can feel absolutely exhausted after too much refined sugar and have a BG reading of 90 mg/dl... "

We are not talking about 'a reaction'. We are talking about a very specific reaction, blood sugar rising too high and staying there for two long, with clear definitions of what those numbers are. That is why I suggested a specific test that anyone can do with a $17 meter (the one I recommeded in an early post is both inexpesive and rated as being very accurate).

3. "But low-carb diets are not an ideal solution, especially for an active person."

What is the source of this information? I am a very active person and I am thriving on a low carb/ high protein diet. I cycle 100-150 miles per week., and weight train ~1-2 hours per week. I have now ridden as far as 68 miles on this diet and felt great (and I only stopped because my son was tired, I could easily and comfortably have done a full century that day). The human body is amazingly adaptable, and can run on many different fuel types. Dr. Cordain is an eminent exercise physiologist with many peer reviewed papers cited in his paleo diet for athletes book. I would follow that plan if my body were more glucose tolerant. However, I can eat even lower carb than he recommends by carefully targeting protein (amino acids can be slowly converted to glucose by gluconeogenesis, I am a professor biochemistry at a major research university and I know what I am doing makes biochemical sense), and low carb veggies can also slowly generate some glucose without a glucose spike. You can also train your body to run on a higher percentage of fat to carbs, which has amazing benefits for weight loss (I have painlessly lost 23 pounds with this approach).

So, what is an 'ideal solution.' That may be very individual. I am not advocating that everyone do this diet, but for me, I perform better on this diet because my blood sugars are stabilized. 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.

4. 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. The idea is with small inputs there are small changes. 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. On this diet I can keep my blood sugars in the 70-120 (OK sometimes it goes up to 130 on the bike........) most of the time. I also ride with a type I diabetic who had to have a pancreas and two liver transplants. My dad was a type I diabetic who died in his 50s. I don't want to end up like them, which is why I follow the diet I do. PLease have Sarah (and her doctor) consider the advice in this book.