Replies to This Discussion

Permalink Reply by Bob on September 25, 2012 at 8:31am

You both may be right about the lack of a hypo response as a result of the slow onset versus feeding off of fat. I'll have to test this down the road (no pun intended) by doing a longer ride and seeing if BS stabilises at some point or continues a slow descent to trouble territory. I guess I am hoping, although admittedly skeptical in the theory, that BS will stabilise at some point and I could do a long distance race without needing to be concerned about fuel or BS levels.

Permalink Reply by FHS on September 25, 2012 at 9:45am

Yeah, I'm not sure about being able to continue working out for an extended period of time with a hypo.

I'm neither low carb nor an endurance athlete. I do a lot of explosive, anaerobic training and I feel that keeping my muscle glycogen reserves topped off is more important than the minimal amount of fat I may or may not burn. Muscle glycogen does not contribute to BG as it's being used so it seems like as long as I have a functional amount of circulating glucose, I can get through a workout.

Ultimately, whether your ketotic or not, it will be your glycogen reserves that will determine how long you can work-out, not fat or ketone reserves.

Permalink Reply by Sick of TYPE 1 on September 25, 2012 at 11:37am

"Ultimately, whether your ketotic or not, it will be your glycogen reserves that will determine how long you can work-out, not fat or ketone reserves."
I find this statement difficult to take at face value- before i could disagree i would have to look into it more - but i know that when i fast my BS is level and yet I have fasted long enough to were glycogen reserves should have been spent (i sometimes work out in a fasted state) -this morning i did an easy 2.5 miles but had not eaten for 33 hours and returned with the same level BS i left with- only had bacon and eggs (no real carb effect and maintained BS through lunch)

Permalink Reply by Lostt on September 25, 2012 at 12:59pm

My own experiences suggest the level of intensity of training vs. the glycogen reserves affects my bg's directly, just depends on the individual as I do more at anaerobic levels than aerobic, just eat differently towards what I am focusing on that day.

Permalink Reply by FHS on September 25, 2012 at 1:31pm

The fact that exercise is glycogen limited, not fat limited, is a pretty robust finding in exercise physiology across a number of different study models and conditions. The bottom line is, when you deplete glycogen, you bonk regardless of fat reserve.

but i know that when i fast my BS is level and yet I have fasted long enough to were glycogen reserves should have been spent (i sometimes work out in a fasted state)

I've definitely exercised after fasting and, back in the days of NPH, I'd have such bad numbers in the morning that I'd regularly exercise before breakfast. Fasting, under usual conditions however, would not deplete glycogen reserves and an easy 2.5 miler probably wouldn't do much to dent glycogen reserves even either, even on top of fasting.

If you think about marathoners hitting the wall and bonking at the 25th to 26th mile and you start to get an idea of the type of effort it takes to deplete glycogen. As a sprinter, it would take something like repeat 400s at 70-80% effort on one day followed by a hard workout the next day to start to feel the effects of glycogen depletion.

Low carbers in ketosis, of course, have low glycogen reserves to start out with which is what puts them in ketosis in the first place. However, this is why Phinney suggests that low carbing somehow makes glycogen use more efficient to explain why low-carb endurance athletes don't suffer decreased performance despite the fact that 1) muscles are glycogen limited, and 2) low-carbers have lower glycogen reserves.

Permalink Reply by Jessica on January 10, 2013 at 3:30pm

Recently, I have been reading about intermittent fasting. It seems to be the craze du jour these days. The benefits touted include increased energy, cognitive benefits and mental clarity, and a great way to "lean up". I strength train 2-3 days a week and do moderate cardio 2-3 days a week. I have found that IF really stablizes my BG so long as I am not strength training. As soon as I throw in strength training (near the end of my 16 hour fast period) my BG spikes to 300+ towards the end of an hour workout.

I can't figure out how to prevent it. I guess I just need to fine tune my insulin. I'm so frustrated and discouraged. Any suggestions from anyone would be greatly appreciated. Thanks in advance!

Permalink Reply by Sheila Fitz on September 21, 2012 at 6:59am

I am still honeymooning, too, but though I'm not running or cycling long distances, I do dance exercise, which is pretty intense. I am able to do two hours of exercise and up to three hours by eating things like eggs with avocados, cheese in the microwave, almond butter on flaxmeal, etc. I carry a sugar spray in a fanny pack that I take to class, and when I've done three hours of exercise, I bring another water bottle with 2-4grams of carb , a vegetable powder. Weights tend to raise my bg. I come home about 95, and don't drop for at least an hour or two, though I usually eat something when I get home. I'm on my third year of LADA without insulin, but I even joined a secondary gym on a Groupon to get enough classes. My bg are 85-95 surrounding exercise. How do I know I'm in ketosis? Truthfully, I've been low carbing and exercising this way for three years, and I'm scared of the way that I felt consuming carbs. I get thirsty if I eat too many low carb vegetables before I work out for the first five to fifteen minutes depending on the intensity. After that, the thirst goes away. I try to consume some extra fat before I exercise, but I don't know what I'm doing. It just works for me.

Permalink Reply by Sick of TYPE 1 on September 25, 2012 at 2:51pm

@ FHS
- in Regard to your reply to my reply i must reply with

" this makes a lot more sense, thankx for putting that out there- yah i guess i was not thinking about what it would take to run me out of my stores *esp since right now my body is trained to hold onto my glycogen with my training for a marathon - thankx for spelling it out maybe next time i will think through things a bit harder before posting"

Permalink Reply by FHS on September 25, 2012 at 8:45pm

No worries. I think it is counterintuitive if you think about what's happening physiologically on a low-carb diet and the fact that low-carb diets seem to work wonders with endurance athletes. I'm trying to keep up with it it because it is a fantastic line of research and I keep looking foward to people like Phinney to really sink their teeth into it.

Permalink Reply by gphx on December 28, 2012 at 8:59pm

With vitamins there is a concept known as bioavailability. Simply put, you can take all the vitamins you want but if the body isn't able to assimilate it, they don't do you any good.

I see glucose and glycogen in T2s in a similar fashion. If one has a great deal of glucose in the bloodstream but is insulin resistant the ports on cells can't open to let it in. Despite the oversupply the person is weak and tired yet the cells tell the body they are hungry and need more and more food because they are truly starving while being bathed in glucose.

A ketogenic diet typically improves the insulin resistance situation in T2s allowing their bodies to utilize existing glucose whether in the bloodstream from diet or produced by the liver.

I used to regularly briskly walk 10 to 14 miles a day and, when I was carb loading, I'd get tired, dizzy, and have to sit down at the halfway point. Then I'd consume a few carbs and be back to my normal and ready to resume. When I cut the carbs back instead I never got tired or dizzy in the first place and could easily do the entire trip in one shot without rest.

Of course brisk walking is not heavy cycling. Just pointing out carb consumption helps people who are not T2 diabetics. For T2 diabetics carb loading often just bogs down the system much as too much gas floods the carburetor of an automobile.

Others may need more details or have different experiences. For myself, less is more. That easy. Only problem with ketotic diets is making sure a restroom is close by. lol

Permalink Reply by gphx on December 28, 2012 at 9:47pm

This article from the ADA Journal suggests a ketotic diet is protective against hypoglycemia. Counterintuitive but matches the experience of many.

Protective Effects of Ketogenic Diets on Signs of Hypoglycemia

Permalink Reply by Jessica on May 5, 2013 at 7:13am

I recently tried Intermittent Fasting, since I was reading so much about in Fitness mags and websites lately. If you are not familiar the basic premise is to not eat after a set time in the evening, say 7pm and then get up in the morning, skip breakfast (coffee or tea is ok), workout in your fasted state and then eat at 11am to break your fast. Then you eat normally from 11am to 7pm and the cycle continues. The benefits are burning stored body fat and it's a great way to lean up an already fit body.

I am a well-managed T1D and I can tell you that when I was IFing (intermittent fasting) I had THE best BG control ever. However, during my workouts I had to stop every 15-20mins and check my BG because your liver starts spitting out glucose to feed your muscles and you have no insulin to counteract it. So I would test, dose insulin and continue. But it was a pain in the ass, really and I wasn't seeing the leaning up that I was hoping for (apparently it's less effective for women - go figure). The artifical pancreas would resolve the liver glucose issues but we'll have to wait a while longer for it to hit the market.

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