Jump to content

Recommended Posts

I'm relatively new to calorie restriction.  I began by doing the 5:2 split and upgraded to doing a water fast on every Tuesday and Thursday.  I'm finding that when I exercise on those days, whether it be cycling or running, I bonk (run out of steam) quickly.  Sometimes I run or cycle for several hours at a clip.  What should I do?  What is the best way to avoid bonking, yet maintaining a CR lifestyle?  Best things to eat during endurance exercise sessions (5 hours plus)?    

Share this post


Link to post
Share on other sites

Reversing,

the proposition that fasting gives you invariably more energy and stamina is often only a myth, although some times in some people it may be true.

 

In my case, I noticed that what gives me the most stamina during exercise is fresh fruit. It requires no gastric digestion, it provides good quality simple carbs, complete with phytochemicals and it's very hydrating.

 

If you train for hours, I believe it becomes impossible to keep unaltered the  caloric amount of a resting day. Where the energy is coming from?

 

The 'cocoon' strategy, adopted ostensibly by some practitioners of CR (I read something about it in old threads of this forum), involves being as still as possible to expend as less energy as possible, and living in a restricted and safe environment to minimize the likelyhood of mortality risk.

 

Such a strategy may not turn out to be so effective, since we know that bones and skeletal muscles need mechanical stress to keep synthetizing tissue.

Share this post


Link to post
Share on other sites

I'm relatively new to calorie restriction. I began by doing the 5:2 split and upgraded to doing a water fast on every Tuesday and Thursday. I'm finding that when I exercise on those days, whether it be cycling or running, I bonk (run out of steam) quickly. Sometimes I run or cycle for several hours at a clip. What should I do? What is the best way to avoid bonking, yet maintaining a CR lifestyle? Best things to eat during endurance exercise sessions (5 hours plus)?

When offered the luxury, I let myself bonk for as long as I feel like it. What's my hurry? I think there's also an adjustment period we need to give our bodies when changing habits, especially if abruptly. Like I do -- sudden change is a kind of stress and the body, poor thing, it's just a mammal and it needs a moment to do whatever it needs to do.

 

I guess the problem is when you need to rest and you cannot rest because of, well, all of ... That.

 

I get enormous energy from fasting now, but it can be inconsistent. Ups and downs might be sharper. Way up I go with loads of sunshine for everything; then way down into sleep for maybe longer than socially acceptable.

Share this post


Link to post
Share on other sites

Mccoy,

 

Thanks so much for your response.  I think your suggestion of consuming some fruit during long exercise sessions is on the money.  I will begin trying that immediately.

 

John  

Share this post


Link to post
Share on other sites

Todd Allen,

 

Thanks for the suggestion!  The book is now in my Amazon shopping cart.

 

John

 

Here's another interesting book from Tim Noakes.  He is a doctor, researcher and an endurance athlete who wrote books on running espousing the traditional carb loading practices.  But several years ago he flipped completely and now is an advocate of LCHF for endurance sports and health.

Share this post


Link to post
Share on other sites

That sounds fascinating and ideally suited for my purposes!  Low Carbohydrate Performance is already on the way and I preordered the paperback edition of Lore of Nutrition.  I'm excited to read both books!

 

Thanks!

Share this post


Link to post
Share on other sites

While endurance athletes may adapt to a low-carb diet and maintain some moderate-intensity performance, it limits high-intensity performance that relies on carbohydrate metabolism, impair exercise economy, and also impairs endurance adaptations. These may not matter if you only exercise at a low to moderate intensity and don't care about competing. See here for a good explanation and linked studies.

 

Then again, CR isn't exactly compatible with high-level performance. It's also important to keep in mind that achieving a relative calorie deficit through exercise (eating more but exercising more) does not have the same benefits as CR (eating less and exercising less). This is what mccoy was referring to, that some (especially early) CR practitioners sought to maximize CR benefits through exercising less so they could eat less. Of course there is some sweet spot with the trade-off in less severe CR affording enough extra calories to gain the benefits of exercise.

 

Here is a good example of this:

 

 

Effect of exercise and calorie restriction on biomarkers of aging in mice

Derek M. Huffman,1 Douglas R. Moellering,1 William E. Grizzle,2 Cecil R. Stockard,2 Maria S. Johnson,1 and Tim R. Nagy1
Am J Physiol Regul Integr Comp Physiol
 
Abstract
Unlike, calorie restriction, exercise fails to extend maximum life span, but the mechanisms that explain this disparate effect are unknown. We used a 24-wk protocol of treadmill running, weight matching, and pair feeding to compare the effects of exercise and calorie restriction on biomarkers related to aging. This study consisted of young controls, an ad libitum-fed sedentary group, two groups that were weight matched by exercise or 9% calorie restriction, and two groups that were weight matched by 9% calorie restriction + exercise or 18% calorie restriction. After 24 wk, ad libitum-fed sedentary mice were the heaviest and fattest. When weight-matched groups were compared, mice that exercised were leaner than calorie-restricted mice. Ad libitum-fed exercise mice tended to have lower serum IGF-1 than fully-fed controls, but no difference in fasting insulin. Mice that underwent 9% calorie restriction or 9% calorie restriction + exercise, had lower insulin levels; the lowest concentrations of serum insulin and IGF-1 were observed in 18% calorie-restricted mice. Exercise resulted in elevated levels of tissue heat shock proteins, but did not accelerate the accumulation of oxidative damage. Thus, failure of exercise to slow aging in previous studies is not likely the result of increased accrual of oxidative damage and may instead be due to an inability to fully mimic the hormonal and/or metabolic response to calorie restriction.

 

 

There is also this Scientific American article that addresses the topic more generally:

 

 

If a diet of caloric restriction can extend the life span of laboratory rats, then does the lifestyle of an athlete, who burns calories at a rapid rate, hasten the aging process?

 
Barbara C. Hansen, professor of physiology in the School of Medicine at the University of Maryland and director of the university's Obesity and Diabetes Research Center, responded as follows:
 
"The effects of caloric restriction on life span in mammals have been demonstrated only among rodents. At present, there are no studies that can definitively say whether caloric restriction extends life span in any primate, so it is premature to draw conclusions about the possibility of extending the maximal human life span.
 
"We are currently researching caloric restriction in nonhuman primates (monkeys). Our monkey study has been going on for 13 years. We began the study on young adult monkeys, equivalent to humans 20 to 25 years old. The animals were placed on a weight-control regimen, designed so they could not put on middle-age weight. We set a monkey's caloric intake for each week based on whether he has gained or lost weight since the previous week.
 
"There are two key issues under study here: Does the average monkey live longer, and is the maximal life span of the monkeys extended? For rodents, caloric restriction has been shown to extend both average and maximal life span. For monkeys, we already know that the animals in our group are living longer than average, if you judge by the 50 percent death point (the time at which half of the animals in the group have died). We have also observed general improvements in health and decreases in disease, which are likely to translate into longer lives. For example, restricting the caloric intake of a monkey sufficiently to prevent the onset of middle-age obesity completely prevents type II diabetes, even though these animals are prone to diabetes.
 
"What we do not know is the effect on maximal life span. Will the longest-lived calorie-restricted monkey survive longer than any other monkey has survived? The monkeys in the University of Maryland study are now at an age equivalent to that of 50- to 60-year-old humans, so we won't know the answer to that question for another 10 to 15 years; monkeys are thought to live well into their thirties under laboratory conditions.
 
"There are two other, related primate studies under way. Richard Weindruch started a similar one at the University of Wisconsin about five year after our own. George Roth and Mark Lane are running a slightly different program at the National Institute on Aging. Roth and Lane are working with several groups of monkeys; they started some of the monkeys on a program of caloric restriction before the animals reached adulthood. This study will produce the best data on the effects of early caloric restriction. It is not yet clear whether early caloric restriction has a net positive or negative influence on health.
 
"We do know enough to say that caloric restriction to prevent obesity during adulthood is likely to be very beneficial, to humans as well as to monkeys. Nobody knows whether the health benefits are because of the positive effects of not having excess adipose tissue or because of altered metabolic activity. My colleagues and I just finished a paper showing that caloric restriction increases the efficiency with which the body burns calories. The problem is, we do not know how that change occurs--that is what we are studying right now.
 
"Incidentally, there is no evidence that excessive leanness is healthy. In fact, most evidence shows that there is an increased mortality associated with excessive leanness. It seems that there is an increasing risk of disease and risk at both ends of the weight range, though probably for different reasons.
 
"Turning back to the original question, we must consider several issues separate from caloric restriction. The lifestyle of an athlete would normally extend life span because it would involve exercise, a healthy diet, absence of obesity, absence of smoking and absence of alcohol and drug abuse (one would hope!). Such behaviors reduce the risk of various diseases, including cardiovascular disease. The athletic lifestyle won't necessarily cause you to live to 100, but it might extend your life span from, say, 70 to 80.
 
"The rapid rate at which an athlete burns calories is not associated with either an increase or decrease in life span. There is, in fact, a theory that animals have only a fixed number of calories to burn during their life, but it is pure speculation, intended to explain why calorie-restricted rodents live longer. There is no evidence that an enhanced turnover rate of calories hastens the aging process. Based on our current level of knowledge, we would expect athletes to have longer or at least healthier lives than they would if they were not athletic.
 
"Exercise, diet and genotype all interact in complicated ways. Despite all our attempts to take our destinies into our own hands, genes seem to play a significant role in determining life span, susceptibility to disease and probably the effects of caloric restriction.

Share this post


Link to post
Share on other sites

Some consider the Tour de France to be a fairly intense and competitive event.

 

https://www.diabetes.co.uk/blog/2016/07/low-carb-diet-propelled-chris-froome-three-tour-de-france-titles/

 

 

While endurance athletes may adapt to a low-carb diet and maintain some moderate-intensity performance, it limits high-intensity performance that relies on carbohydrate metabolism, impair exercise economy, and also impairs endurance adaptations.



 

 

Edited by Todd Allen

Share this post


Link to post
Share on other sites

 

Some consider the Tour de France to be a fairly intense and competitive event.

 

https://www.diabetes.co.uk/blog/2016/07/low-carb-diet-propelled-chris-froome-three-tour-de-france-titles/

 

 

While endurance athletes may adapt to a low-carb diet and maintain some moderate-intensity performance, it limits high-intensity performance that relies on carbohydrate metabolism, impair exercise economy, and also impairs endurance adaptations.

 

 

 

Chris Froome also recently ran into drug test problems: https://www.theguardian.com/sport/2017/dec/13/chris-froome-team-sky-reputation-abnormal-drug-test- he's probably not the best example.

Share this post


Link to post
Share on other sites
James Cain: While endurance athletes may adapt to a low-carb diet and maintain some moderate-intensity performance, it limits high-intensity performance that relies on carbohydrate metabolism, impair exercise economy, and also impairs endurance adaptations.

 

 

See previous discussion and links here:

 

https://www.crsociety.org/topic/12644-mcglothin-cr-way-believes-high-fat-intake-causes-cognitive-decline/?do=findComment&comment=22746

Edited by Sibiriak

Share this post


Link to post
Share on other sites

I'm so glad I posted this!  This is precisely what I hoped to inspire!  Vigorous debate!

 

I want to compete in an ultra marathon.  I also want to practice a CR (intermittent fasting) lifestyle.  So, the question is, what is the best way to find  balance between my need to train for hours at a time and my desire to practice intermittent fasting. 

 

Right now, I do a water fast Tuesdays and Thursdays.  I have just received one of the books recommended above and will read it soon.    

 

I think eating complex carbs and healthy fats during long training sessions is the way to go.  I see ultrarunners loading up on pizza and soda and candy and caffeine.  It blows my mind. 

 

In response to Barbara C. Hansen quote above: How does she explain that the average ultra runner's telomeres are the length of the average person 17 years their junior?

Share this post


Link to post
Share on other sites

As an aspiring ultra marathoner you might find the following website interesting, roughly weekly blog posts and podcasts exploring low carb diets with respect to athletics, especially endurance sports and muscle building.

https://theketogenicathlete.com

Podcast episode 57 with Zach Bitter and episode 15 with Tim Noakes are good ones to start with.

 

As someone with a muscle wasting disease recovering from a deep decline I've found this approach helpful, but my goals are quite different from most of those here practicing CR.

Edited by Todd Allen

Share this post


Link to post
Share on other sites

I'm so glad I posted this!  This is precisely what I hoped to inspire!  Vigorous debate!

 

I want to compete in an ultra marathon.  I also want to practice a CR (intermittent fasting) lifestyle.  So, the question is, what is the best way to find  balance between my need to train for hours at a time and my desire to practice intermittent fasting. 

 

Right now, I do a water fast Tuesdays and Thursdays.  I have just received one of the books recommended above and will read it soon.    

 

I think eating complex carbs and healthy fats during long training sessions is the way to go.  I see ultrarunners loading up on pizza and soda and candy and caffeine.  It blows my mind. 

 

In response to Barbara C. Hansen quote above: How does she explain that the average ultra runner's telomeres are the length of the average person 17 years their junior?

 

The only way to combine ultra marathon training and IF to me seems banally to eat huge, gargantuan meals once a day, maybe at night after the training has ceased. don't know if that's an healty proposition. 

Share this post


Link to post
Share on other sites

Addressing the topic at hand, I don't think it's a good idea to train vigorously on fasting days. I would be especially concerned about becoming light-headed while cycling and crashing, drifting off the road, into traffic, etc. Occasionally I hear of people who do train while water-only fasting - they seem to be the exception rather than the rule. Anything other than walking, usual chores, and so forth just seems risky to me. 

 

Last summer when I was triathlon training I would eat dates and drink coconut water (mainly for the electrolytes) during long training sessions in the heat (I went as long as 2 hours, not anywhere near your 5 hours). 

Edited by drewab

Share this post


Link to post
Share on other sites

Todd Allen,

 

Many thanks!  I will be listening to the episode you suggest tomorrow.  I have a feeling the website you suggest is ideal for me.  I look forward to familiarizing myself with it.

 

Thanks Again,

 

John

Share this post


Link to post
Share on other sites

Mccoy,

 

I do strength training Monday, Wednesday, and Friday.  I run or cycle, often for hours, on Tuesdays, Thursdays, and Saturdays.  I have been doing water fasts Tuesdays and Thursdays, but I'm finding it extraordinarily difficult to fast on days during which I exercise for more than an hour.  Today, I ran 12 miles in a fasted state.  

 

I am thinking that I have a few options. 

 

Option 1 - Switch my two fast days to Mondays and Wednesdays because I don't have very long workouts on those days.

 

Option 2 - Eat 500 calories (as suggested in 5:2 diet) on Tuesdays and Thursdays when I train for more than an hour.

 

Option 3 - Instead of fasting two days every week, do a 3 day water fast once per month.

 

I guess some variation of one or more of these options could also be considered.

 

What do you, or anyone else with any deep insight into this type of matter, think would be ideal?

 

Thanks,

 

John 

Share this post


Link to post
Share on other sites

Drewab,

 

I hadn't even considered that aspect of it.  But you're right.  It's just not a good idea.  I need to find a more suitable way.

 

Thanks,

 

 

John

Share this post


Link to post
Share on other sites

If you aren't eating a ketogenic or near keto diet then I believe it typically takes several days of fasting before muscles transition from burning ketones to primarily burning fatty acids, sparing ketones for the brain.  Then blood ketone levels rise quickly into the 4 to 8 mmol/l range and one becomes quite resistant to bonking hard where mental functions can be impacted due to falling blood sugar.   But your performance will still be limited by the rate at which your muscles can metabolize fatty acids.  The rate at which muscles can burn fatty acids improves dramatically with time spent with the muscles in a fat burning state.  This process has been dubbed "fat adaptation" and it typically takes a few months.

Share this post


Link to post
Share on other sites

Todd Allen,

 

I listened to the podcast at the Ketogenic Athlete that you recommended.  It was fantastic and really started to make me think about adopting a ketogenic diet and merging it with my 5:2 fasting routine.  And then I quickly devoured the book you suggested, "The Art and Science of Low Carbohydrate Performance."  Both the podcast and the book have fully converted me.  I plan to begin easing my way into ketosis and seeing how it goes.  I know it will take some time to become fully fat adapted.  I'll be using keto strips to test my urine daily.  I've also changed my fasting days so that they always fall on days when I am lifting weights, not running.

 

Thanks So Much,

 

 

John

Share this post


Link to post
Share on other sites

Just checking in to see how it's going.  The most common issue is electrolyte depletion especially sodium and sometimes magnesium for those who don't eat a lot of greens.  I encountered this due to having very little sodium intake through avoidance of processed foods and had to learn the habit of salting my food.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×