Unlimited Carbs Post Workout?

Diet and Nutrition
1

I was reading Lyle McDonald’s Protein Book and I came across a statement in which he seems to suggest that, provided the workout is intense enough, no fat gain can result from the intake of carbs immediately post workout.

The statement is this:
[DISCLAIMER: small parts of the book are allowed to be publicly quoted, according to the author, if it’s for discussion purposes]

Research has repeatedly shown that muscular insulin sensitivity is up regulated following
both resistance and endurance training although the mechanisms are different for each
type of training (69). Improvements in insulin sensitivity also depend on the total
amount of training done with a threshold caloric expenditure of 500-900 calories per
workout being necessary (70,71). […]
The training induced increase in insulin sensitivity is likely to be a major mechanism
behind the “window of opportunity” following training, skeletal muscle is primed to take
up nutrients at an accelerated rate. This means that the chance of calories being pushed into fat storage is minimized if not eliminated. […]
following glycogen depleting endurance exercise, research has clearly shown that the ingested carbohydrates go towards glycogen storage while the body continues to rely on fatty acids for fuel. This occurs despite an increase in insulin levels from the carbohydrates.
This holds true for massive carbohydrate intakes as well. In one study, subjects were given 5 g/kg of carbohydrate (500 grams carbohydrate for a 100kg athlete) following 90 minutes
of moderate exercise and de novo lipogenesis (DNL, the conversion of carbohydrate to fat)
was studied; not only did no DNL occur but the body continued to burn fat in the post-
exercise period (74). Essentially, when glycogen is depleted from training, incoming
carbohydrates go to glycogen storage while the body continues to use fatty acids for fuel;
raising insulin post-workout does not interfere with this.

While I already knew that carbs are less likely to be stored as fat when consumed post workout, the claim here is that, provided the workout is intense enough (in this case this reads as: burns enough calories from muscle glycogen), a massive (virtually unlimited?) amount of carbs can be consumed up to 90 minutes following the session, with virtually none of it being used towards fat storage.

How does this statement relate to your experience?

Does this mean that excess carbs are oxidized for energy or are they actually uptaken by the muscle for glycogen repletion and growth?

2

Logically the disclaimer ‘IF its intense enough’ means that the statement can’t really be wrong. Some of the carbs were stored as fat you say? well the workout wasn’t intense ENOUGH.

Realistically there is a finite capacity to muscle glycogen, so logically there will be a limit to what you can store before your body will turn it into fat.

However there is also a limit to the rate you can digest carbohydrates in different forms, which is something else that might be worth considering.

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3

Correct, but the author also seems to be giving concrete numbers.

He mentions 500-900 calories burned during exercise (he doesn’t specify but I’m assuming they must be calories from glycogen), and up to 5 g/kg of carbs.

So for me, since I weigh 75 kg, that’d mean 375 g of carbs in the post workout meal alone! That’s about what I eat in a whole day when gaining mass.

So assuming a person of my weight does a full body training session with moderately high volume (20ish sets of big lifts), which would most definitely provide that caloric threshold, while also involving and sensitizing the most muscle mass, can there really be any merit to consuming nearly 400 g of carbs following it?

And since you mentioned speed of digestion, I’m referring to something realistical enough like white rice (so a high-GI but solid food).

If so, would it make any sense to eat other carbs during the day at all (excluding pre-workout supplementation)? I feel that could drive up calories significantly and since glycogen stores would most likely be already topped because of that meal, it would only contribute to fat gain by means of lipogenesis.

5

Scratch that, burning 900 calories and eating 2000 calories of carbs with no fat gain would be an incredible finding, though a doubt most people can achieve 900 calories burned in a time frame short enough before the workout becomes so long the detrimental effects of prolonged cortisol elevation on insulin sensitivity start to counter the effect.

6

It might be worth trying though.

Starting June, I’ll do Dan John’s “10 secrets to building mass” program, which is a full body, 3 times per week program.

The program is based on high ish rep squats and movements such as clean and presses, bench presses, rows, pull ups, and carries. This looks like the perfect combination to try this.

Workout supplementation might be a way to prevent this from being a problem. Following the recommendations he gives for workout supplementation in his book (which I strongly suggest the reading of), I came up with this protocol:

1 hour pre workout (first meal of the day, training in the morning)
35 g dextrose
35 g whey isolate

Immediately pre workout
20 g highly branched cyclic dextrin
15 g peptopro (casein hydrolizate)

During workout
20 g dextrin
15 g peptopro

(so I’ll just make a drink with 40 g cyclic dextrin and 30 g peptopro and drink half of it at the beginning of the workout and the other half during)

This should keep blood sugar and AA levels stable, while decreasing cortisol output during the session.

And then, I might consider consuming a monster 300 g of carbs after. What do you think?

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7

The peri workout plan looks absolutely sound, though I think this would offset some of your post workout allowance, as calories consumed will offset calories burned from glycogen, unsure whether McDonald factors that into his testing? Otherwise does look like a good plan and worth testing.

If you are looking for maximum gains I suspect it will be very anabolic and very effective.

If, like me, you like ways to be ‘allowed’ to eat more carbs, I think it will be disappointing because you would probably need to consume most of the post workout carbs again in the form of cyclic dextrin or glucose for the absorption to be quick enough to take advantage of the post workout physiological changes. I think 300+ grams of carbs from a longer chain source would probably not all be digested within that 90 minutes.

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I’ll go back to the chapter and read it again, but if I’m not mistaken he says that most of the studies mentioned were performed on fasted subjects (NOT sure here, he mentioned it but I can’t remember right away whether that applied to the study I quoted too).

The fact of the matter is that this summer I’ll have the opportunity to have my post workout meal right after my session, as I’ll be training in a gym very close to my mum’s place. This would make a post workout drink ineffective, because I’d eat solid food right after it.

I might split my hypothetical carbs and consume 1/3rd of it in the form of Dextrose (I know dextrin would be more effective in terms of speed, but really 100 g of dextrine is expensive) and have the remaining 2/3rds in the form rice, with about 40 g of protein from chicken breast and no fat. How’s that look?

Theoretically, including a faster, liquid source of carbs right after the workout I should be able to get an upstart on digestion even before I hit my plate of rice.

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9

A few starter thoughts: 1) The proportion of calories burned from glucose (liver and muscle glycogen), varies drastically with the rate of caloric burn. For example at mild exercise level of around 300 calories per hour, typically only about 33% of the calories is coming from glycogen stores. That would be about 25 grams of glycogen depleted per hour. At 600 kcal/hour, glycogen depletion accounts for about half of calories burned or about 75 grams of carbs (triple) and at 900 kcal per hour >67% comes from glycogen or 150 grams of carbs. (for say a 185 pound male). That means that a three fold increase in calories burned in an hour yields a six fold increase in muscle and liver glycogen depletion. One would need to know the intensity in terms of METS in the study. 2) Higher fat, lower carb dieters have more fatty acids in their muscles and less glycogen. They will tend to increase fat mobilization rather than deplete liver glycogen and burn proportionately less glycogen at each intensity level. They will also not have the same increase in insulin sensitivity following intense training because they free up less muscle volume (fat has more energy per volume than muscle glycogen by far, about 10 to 1). Since low carb dieters use more more muscle FFAs and less glycogen, the FFA depletion clears a lot less space for ingested carbs to load up. 3) Fat (sans ketones) can not provide enough energy to fuel long workloads at high calorie outputs. In fact at about 600 kcal an hour, fat burning is at 100% of capacity, and the capacity drops over time as glycogen gets depleted. Most research I have seen shows that this leads to a big spike in cortisol, adrenaline and glucagon at around the point that 75 grams of total glycogen has been depleted (about an hour at 600 kcal/hour, or a half hour at 900 kcal/hour). At that point, gluconeogenesis is upregulated and muscle protein breakdown spikes, and insulin sensitivity is REDUCED by the increase in catecholamines. This starts to make it harder for muscle and liver to absorb glucose.

(I would need to know how soon post workout the carbs were consumed and the MET level of the training to go much further, but basically your body starts to resist glycogen depletion when glycogen is depleted by about 15% by increasing gluconeogenesis. Longer, harder workouts further increase insulin resistance int he short term and provide no further increase in testosterone or GH. Seems to happen within 45 minutes of high intensity training.)

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10

I will come back as soon as I have time and read your post in more detail but for now here’s the deal:

They seem to have been consumed within 90 minutes, following the workout.

There are study citations at the end of the book, tonight I’ll take a look and provide you with a link to the study if applicable.

To my understanding, this would be limited by including peri workout carbs that as a side effect would lower cortisol (whose primary function would indeed be to provide glucose by robbing other tissues like the muscle, right?).

So in a situation where the workout ends up being like the one I linked to (so around 20 total sets of exercises for every muscle group, with the rep range being 5-10 reps/set), and the workout supplementation being the one I proposed above, would you find any merit to consuming a very large portion of carbs immediately post workout (300 g) in the form of Dextrose AND THEN white rice?

This in face of the fact that the intensity of the workout would be that of a standard weight training session with lower- and higher-rep sets, and that my diet consists of more carbs than fat (maybe a 5:1 ratio in terms of GRAMS of each nutrient).

11

No. There is a more fundamental question first. If someone burns 500-900 calories, or 125-225 grams of “fuel” (even if 100% comes from glycogen), and their muscles and liver absorb 500 grams of new glucose, (not even accounting for the associated water mass), with no decrease in fat burning, then they would gain at least 275-375 grams in the form of lean body weight each time they did so. In reality they would gain about 4 times that much because of the water associated with glycogen. So we have about +1 kilogram of hydrated muscle and liver glycogen added to the body every time this is done IF we accept the study at face value. As a result, I have to start with the assumption that there is something wrong with the study, and look for what error there is or where their conclusions have gone too far.

Adding carbs peri-workout will reduce cortisol release but it will also block lipolysis. Anyway, your protocol would depend on whether your diet is more carb based or fat based since post workout insulin sensitivity is increase more in people who eat higher carb diets and less in people who eat higher fat diets. At any rate, it seems unlikely that you can get more than about 75 grams net glycogen depletion from a workout without activating some counter-regulatory hormones.

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The study was, at least according to the extract, measuring DNL, not scale weight, to determine what was happening in the post workout window, so I’m missing the relevance of the weight of glycogen and water retention.

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13

I think @mertdawg is getting at:

  1. You burn 125-225 grams of glycogen in the absolute perfect case workout (burning 100% cho). It will likely be way less than this.

  2. You eat 500 grams of carbohydrate in the 90 minute PWO window.

  3. You haven’t increased your glycogen storage capacity over one workout. Those extra 275g of carbs have to go somewhere (assuming they were full before).

  4. Even if de novo lipogenesis doesn’t happen in the PWO phase, all that glucose has to go somewhere once muscle/liver stores are full.

Typical number for total body glycogen storage is 50-120g in Liver and 350-400g in muscle. So we’re talking max 520g.

Start at 520g
Burn 225g
Unused capacity: 295g
Eat 500g
Total glucose in the body: 795g
Less 520g storage capacity
275g extra CHO with nowhere to store.

This is of course assuming zero thermic effect of food or energy loss in storing the carbs as glycogen, and I’m just looking at the workout in a vacuum. Obviously total energy balance for the day matters most. But that simple math shows 275x4=1,100 calories more than you need to resupply what you burned during the workout.

I think the OP’s decision to try it out at 300g is probably way more prudent. Let us know how it works OP.

14

Yeah but my intent here it still to try and consume a very high amount of carbs in a small window to see if some extra anabolic effect ensues.

At 75 kg of bodyweight, 300 g are 4 g/kg of carbs, which is lower than the study quoted by the book, but more realistical and, as you said, prudent (taking into consideration that the study used “endurance training,” which progsbly burns more glycogen than medium rep weight training), and still a very high amount for a single meal.

Sure thing, so my question is:

I’m assuming you think my plan to consume 300 g of carbs post workout, together with the pre workout supplementation plan I laid out in my previous post looks good (is this correct?), once I have consumed 375 g carbs (my pre and intra workout carbs add up to 75 g) in the workout period, how should I go about eating carbs for the rest of the day?

Assuming I want to gain weight, and I have found through trial and error that I need to eat about 3,700 kcal a day to gain weight at a decent rate (at first I’ll probably go lower than that as I will have dieter for some months), and eating around 180 g of protein (so around 1.1 g/lb), how should I divide those remaining ~1,500 kcal?

I might consume around 100 grams of fat a day and an additional 150 g divided into the other meals (mainly before bed to optimize during-sleep recovery and serotonin production).

What I’m worried is that, since I’ll be replenishing my glycogen storages with that first post workout meal, even though it won’t result in fat gain itself, all the subsequent carbs consumed during the day will lead to fat gain.

Hope that makes sense; thoughts?

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As I alluded to in my last post, I’m a very high carb dieter (I can go very low fat without even noticing but I’m just too comfortable eating lots of carbs).

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I’m just a weekend warrior who can do math. I say try it and see if it works for you. Look up “carb backloading”. It was a fad that burned out because some of the science cited by the author wasn’t quite right. There were threads on t-nation raving about it. The general gist:

Skip breakfast. No carbs at lunch (salad and meat).
Train around 1pm.
Smash carbs PWO and into the evening.

17

I mentioned that if you burn 900 (pure glycogen) and eat 2000, you would net 275 grams of lean bodyweight plus the associated water every time you did this, but as @Basement_Gainz alluded to, this would assume no thermic effect of the food. When I said, “If we accept the study at face value” I meant "IF we assume that the total additional energy expendature of the process was the 900 calories. When I mentioned possible reasoning errors in the study, one would be that the study failed to account for additional energy expendature.

The other is that there is no reduction is lipolysis over the next 24 hours. A maximally glycogen loaded muscle is more insulin resistant than a somewhat depleted one. A glycogen loaded liver will tend to release more glucose, and triglycerides into the blood stream over a 24 hour period. Typically, at rest, and outside of a meal window, the liver releases 3-5 grams of glucose into the bloodstream per hour which requires the pancreas to match with basal insulin. If the liver is highly loaded, it can release up to about double this amount (6-10 grams) of glucose per hour requiring higher basal insulin to balance. That insulin will reduce hormone sensitive lipase levels in the fasting state and decrease utilization of adipose and can happen for 6-12 hours after a very large carb meal. So this may be the mechanism that irons out the numbers. Its not necessarily bad, but it might support the strategy that this should be done earlier in the day (early dinner?) so that night time basal insulin levels are not pushed up. If muscle glycogen gets reloaded over 24 hours anyway, what are the benefits of pushing them all in at once? If you burn calories or create a calorie deficit, you will become more insulin sensitive quickly.

Also, I will have to look at the study to see if the subjects experienced the same effect for several days in succession. And what was there nutritional and training status before the experiment. Did they see the same results for say 30 days in a row?

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I’ll be training in the morning and this meal will be eaten at around 1pm so that’s luckily one less thing to worry about.

I think the logic is that glucose will be uptaken more effectively since the acute increase in insulin sensitivity is said to go down after some hours.

That should be accomplished via the training session.

Creating a deficit really isn’t an option as this plan is for mass gaining.

I’ll link to the study this evening and take a closer look at your post but for now, what’s the verdict?

Do you think my plan (so also the 150ish g of carbs that I would consume during the rest of the day) is better than speeding carbs more throughout the day?

19

So I just watched this with Lyle McDonald, not realizing that he authored your article.

At 12:50 he says that “you can do some magic tricks for about 24 hours. If you deplete muscle glycogen completely, and then jack in a bunch of carbs for a day, your body will store the carbs and keep burning bodyfat.” Published Sept 30 2017

His book was published in '07 and his explanation on the podcast seems to have a lot more conditions and restrictions than the description in the book.

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Lyle catches allot of crap for speed skating and DYEL on his own forum. It’s not entirely undeserved despite his knowledge.

That beard game though!

Screenshot_20180509-145903
Screenshot_20180509-1459031920×1080 280 KB

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That occurred to me. I had not heard of him before. Still, he does not seem to be endorsing regularly eating unlimited carbs after each workout.