Thank you for these important clinical observations! In my experience protein is a key component in reducing reactive hypoglycemia. It has been postulated that this is due to protein not only being insulinogenic but also stimulates glucagon and thus helps the body ‘balance’ blood glucose levels. Could this be an additional effect that you are observing? Love to hear your thoughts!
Something to factor in with protein guidelines and high-volume endurance athletes is how much protein (and everything) they should be eating due to their total output
When I'm in-season, I'm training ~3 hours a day(avg). This past summer, I did a doubly labeled water study (Calorify) and that had my "burn" at 4000kcal per day.
At any reasonable split (Pro, Fat, Cho) I'll be well above standard guidelines for protein.
The numbers above are as a 55 yo male. When I was younger, and racing elite, my volume was higher and my intake was higher, too. Unfortunately we didn't have DLW studies back then but there have been a few done on modern high-volume elite triathletes.
Thanks Gordo - yes I am in agreement. For folks doing a 3hrs per day, agree completely - hitting protein targets tend to just happen naturally. I think there's a bit of a grey area though when people are doing eg 60-90mins - especially when they are older, 1) because overall kcal intake is not as high; and 2) we seem to get less efficient at using protein as we age. But thanks for your comment and I love that you did DLW! I'll have a read of your blog!
I am very interested in this topic as I'm in a related situation. I do significant strength and endurance training, and recently tracked by blood glucose with a CGM. In that tracking I often saw these very rapid spikes and overshoots after meals. However, I do already eat a high protein diet (~1 g / lb body mass), and some of the greatest spikes I saw were (1) in the morning and (2) with high protein breakfasts (whey protein and cut up fresh fruit). My background is in theoretical biology and signal transduction networks. Given that and my data, my current working hypothesis for these rapid peaks and overshoot is:
(1) Exercise routine means I have an unusually high calorie intake, and a high protein intake. I also have an unusually large amount of skeletal muscle.
(2) The carbohydrates and protein sources I consume both trigger insulin release. Whey protein in particular is has a very high insulin index.
(3) After periods of fasting (such as sleeping), my body and skeletal muscle in particular upregulate insulin receptors to the cell surface. At the same time, my pancreas synthesizes insulin and stores it in endosomes for release during the day.
(4) During breakfast, my body releases a pulse of insulin to a very insulin sensitive body when it senses the intake of protein and glucose (15 min after eating)
(5) The pulse is calibrated to drop the glucose levels, but is dosed in response to the protein AND glucose, so causes and overshoot and a glucose crash (30 min after eating)
(6) The glucose stays low due the large quantity of skeletal muscle and its insulin sensitivity. That tissue takes up glucose for 15 minutes even if glucose is low.
(7) Eventually the liver clears out the remaining insulin and the blood sugar returns to normal (1 hr).
Part of the issue here I suspect is that the meal I'm eating is eaten quickly (I'm in a hurry in the morning) and is rapidly digested (whey and fruit). My simple solution is to spread my meal out over a longer time. I suspect this would work irrespective of the amount of protein I consume, but particularly with high insulin stimulating protein sources such as whey.
What do you think? Does this seem plausible or are there better ways to understand / test/ validate this?
Thanks Peter - I think your point 4 is really important - that you're getting a shot of insulin at the moment when you are most insulin sensitive (as we are in the morning). But to me while it's a reasonable suggestion for the glucose dip, it doesn't seem to explain the rapid rise in glucose. In general, a rapid and high glucose rise suggests the first phase insulin machinery is not responding as it should......
That makes sense. It is almost as if there is a delay in response which causes the overshoot. Such a delay could be responsible for a bunch of the variation--it is the same problem we encounter when trying to get the temperature right in the shower. The delay of water flowing down the pipe from the valve means we are alternatively scalded and frozen before we get the right shower temperature.
I'm at a loss to explain the physiological mechanism of such an insulin delay though... Treatment wise, again we could follow the shower control strategy of just making changes slowly so that the delay is less relevant and the excursions less extreme.
I’m not an athlete, just a 55yr old woman on HRT trying to keep healthy with weekly Zumba, circuits with weights, X3Bar weight lifting x 4, Pilates x 3, and daily hour long hilly dog walks ( weighted vest in post!) but my blood glucose is always too high & in line with my HbA1c of 5.7%. I’ve been low carb, paleo with dairy, IF 18/6 for 8yrs. I’ve put on subcutaneous fat over last couple of years. 5yrs ago my fasting glucose was 4 (mmol/L) and insulin was 2. Now on waking glucose is 6, it goes up to 7 after an hr, stays at 7 after dog walk, got to a max of 8.2 after extreme weights lifting session. Gets down to 5.5-6 prior to first meal at 1pm. Goes up to 7, then down within 2hrs ( no hypos). Is more like 5-5.5 prior to supper. It only gets reasonable with extended fasts of 36hr, then glucose is 4.5ish, ketone 1.5. By 48hrs glucose is 4 & ketones are 3, and a 72hr fast got glucose of 3.5 & ketones of 4.4.
Why is my glucose always too high despite low carb for 8yrs? Total ( not net) carbs were 30-50g with an absolute max of 100mg if I was naughty! Recently I’ve been strictly 20g or less - no difference.
Is it
1) too much progesterone making my body think it’s pregnant - can’t reduce it though
Thanks for sharing your fascinating clinical observations and hypotheses about blood glucose regulation in athletes! I'd love to hear you discuss this with an exercise physiologist. I've had symptomatic reactive hypoglycemia (and high peaks) for many years. UCSF endocrinologist told me 40mg/dL (2.2 mmol/L) was 'normal' for a thin fit woman during an OGTT. I wonder if further elucidation of glucose regulation mechanisms in athletes might also help people like me who are moderate exercisers. Higher protein+fat meals allow me to avoid lows and based on your post I'm interested to try higher protein without the higher fat.
Let me know how it works for you. I think it's important to note that we are just discovering how complex the beta-cell is - maybe in some people it does just erratically overshoot (maybe some genetic involvement?), and although we do have cut-offs for "normal", maybe there are some people who naturally fall outside these ranges but it's not necessarily pathological or anything. I think Kara makes a good comment above- maybe protein might help manage this by counteracting insulin as people fall into the hypoglycaemic range...Thanks for your comment!
I’m not an athlete and nor is my sister and we both get huge glucose spikes and reactive hypoglycemia. I think it’s the first phase insulin response. Solved by less carbs or never eat carbs without a lot of protein and fat.
Thank you for an insightful view. Very interesting subject. I also find interesting that some people are normalising equally pain and suffering as well as effort and discomfort.
Thank you for these important clinical observations! In my experience protein is a key component in reducing reactive hypoglycemia. It has been postulated that this is due to protein not only being insulinogenic but also stimulates glucagon and thus helps the body ‘balance’ blood glucose levels. Could this be an additional effect that you are observing? Love to hear your thoughts!
that's interesting - that's a really good point. I am still curious though why a dip occurs anyway - this suggests insulin is overshooting somehow.
Something to factor in with protein guidelines and high-volume endurance athletes is how much protein (and everything) they should be eating due to their total output
When I'm in-season, I'm training ~3 hours a day(avg). This past summer, I did a doubly labeled water study (Calorify) and that had my "burn" at 4000kcal per day.
https://feelthebyrn.substack.com/p/burn-part-three
At any reasonable split (Pro, Fat, Cho) I'll be well above standard guidelines for protein.
The numbers above are as a 55 yo male. When I was younger, and racing elite, my volume was higher and my intake was higher, too. Unfortunately we didn't have DLW studies back then but there have been a few done on modern high-volume elite triathletes.
Thanks for your writing - I find it interesting.
G
Thanks Gordo - yes I am in agreement. For folks doing a 3hrs per day, agree completely - hitting protein targets tend to just happen naturally. I think there's a bit of a grey area though when people are doing eg 60-90mins - especially when they are older, 1) because overall kcal intake is not as high; and 2) we seem to get less efficient at using protein as we age. But thanks for your comment and I love that you did DLW! I'll have a read of your blog!
I am very interested in this topic as I'm in a related situation. I do significant strength and endurance training, and recently tracked by blood glucose with a CGM. In that tracking I often saw these very rapid spikes and overshoots after meals. However, I do already eat a high protein diet (~1 g / lb body mass), and some of the greatest spikes I saw were (1) in the morning and (2) with high protein breakfasts (whey protein and cut up fresh fruit). My background is in theoretical biology and signal transduction networks. Given that and my data, my current working hypothesis for these rapid peaks and overshoot is:
(1) Exercise routine means I have an unusually high calorie intake, and a high protein intake. I also have an unusually large amount of skeletal muscle.
(2) The carbohydrates and protein sources I consume both trigger insulin release. Whey protein in particular is has a very high insulin index.
(3) After periods of fasting (such as sleeping), my body and skeletal muscle in particular upregulate insulin receptors to the cell surface. At the same time, my pancreas synthesizes insulin and stores it in endosomes for release during the day.
(4) During breakfast, my body releases a pulse of insulin to a very insulin sensitive body when it senses the intake of protein and glucose (15 min after eating)
(5) The pulse is calibrated to drop the glucose levels, but is dosed in response to the protein AND glucose, so causes and overshoot and a glucose crash (30 min after eating)
(6) The glucose stays low due the large quantity of skeletal muscle and its insulin sensitivity. That tissue takes up glucose for 15 minutes even if glucose is low.
(7) Eventually the liver clears out the remaining insulin and the blood sugar returns to normal (1 hr).
Part of the issue here I suspect is that the meal I'm eating is eaten quickly (I'm in a hurry in the morning) and is rapidly digested (whey and fruit). My simple solution is to spread my meal out over a longer time. I suspect this would work irrespective of the amount of protein I consume, but particularly with high insulin stimulating protein sources such as whey.
What do you think? Does this seem plausible or are there better ways to understand / test/ validate this?
Thanks Peter - I think your point 4 is really important - that you're getting a shot of insulin at the moment when you are most insulin sensitive (as we are in the morning). But to me while it's a reasonable suggestion for the glucose dip, it doesn't seem to explain the rapid rise in glucose. In general, a rapid and high glucose rise suggests the first phase insulin machinery is not responding as it should......
That makes sense. It is almost as if there is a delay in response which causes the overshoot. Such a delay could be responsible for a bunch of the variation--it is the same problem we encounter when trying to get the temperature right in the shower. The delay of water flowing down the pipe from the valve means we are alternatively scalded and frozen before we get the right shower temperature.
I'm at a loss to explain the physiological mechanism of such an insulin delay though... Treatment wise, again we could follow the shower control strategy of just making changes slowly so that the delay is less relevant and the excursions less extreme.
I’m not an athlete, just a 55yr old woman on HRT trying to keep healthy with weekly Zumba, circuits with weights, X3Bar weight lifting x 4, Pilates x 3, and daily hour long hilly dog walks ( weighted vest in post!) but my blood glucose is always too high & in line with my HbA1c of 5.7%. I’ve been low carb, paleo with dairy, IF 18/6 for 8yrs. I’ve put on subcutaneous fat over last couple of years. 5yrs ago my fasting glucose was 4 (mmol/L) and insulin was 2. Now on waking glucose is 6, it goes up to 7 after an hr, stays at 7 after dog walk, got to a max of 8.2 after extreme weights lifting session. Gets down to 5.5-6 prior to first meal at 1pm. Goes up to 7, then down within 2hrs ( no hypos). Is more like 5-5.5 prior to supper. It only gets reasonable with extended fasts of 36hr, then glucose is 4.5ish, ketone 1.5. By 48hrs glucose is 4 & ketones are 3, and a 72hr fast got glucose of 3.5 & ketones of 4.4.
Why is my glucose always too high despite low carb for 8yrs? Total ( not net) carbs were 30-50g with an absolute max of 100mg if I was naughty! Recently I’ve been strictly 20g or less - no difference.
Is it
1) too much progesterone making my body think it’s pregnant - can’t reduce it though
2) too much protein-80-140g (5’2” & 63kg)
3) just because I’m overweight-but why?
Thoughts?!
Thanks for sharing your fascinating clinical observations and hypotheses about blood glucose regulation in athletes! I'd love to hear you discuss this with an exercise physiologist. I've had symptomatic reactive hypoglycemia (and high peaks) for many years. UCSF endocrinologist told me 40mg/dL (2.2 mmol/L) was 'normal' for a thin fit woman during an OGTT. I wonder if further elucidation of glucose regulation mechanisms in athletes might also help people like me who are moderate exercisers. Higher protein+fat meals allow me to avoid lows and based on your post I'm interested to try higher protein without the higher fat.
Let me know how it works for you. I think it's important to note that we are just discovering how complex the beta-cell is - maybe in some people it does just erratically overshoot (maybe some genetic involvement?), and although we do have cut-offs for "normal", maybe there are some people who naturally fall outside these ranges but it's not necessarily pathological or anything. I think Kara makes a good comment above- maybe protein might help manage this by counteracting insulin as people fall into the hypoglycaemic range...Thanks for your comment!
I’m not an athlete and nor is my sister and we both get huge glucose spikes and reactive hypoglycemia. I think it’s the first phase insulin response. Solved by less carbs or never eat carbs without a lot of protein and fat.
Thank you for an insightful view. Very interesting subject. I also find interesting that some people are normalising equally pain and suffering as well as effort and discomfort.