Tag Archives: exercise

Ketones inhibit lipolysis

Petro just posted a brief article about acipimox & the insulin hypothesis.  Similar to insulin’s forte, acipimox inhibits lipolysis.  This leads to expansion of adipose tissue, and eventually, weight gain.

Acipimox acts on the same receptor as niacin and ketones, GPR109a.  That is, all three of those agents inhibit lipolysis.  We’ve discussed some of the implications of this on fuel partitioning HERE.

 

ketone-supp-physiology

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The poor, misunderstood autophagy

Autophagy isn’t a big deal in the way some Internet Bro’s think it is.  Yes, Dr Ohsumi received a Nobel Prize for cracking deeply into this nut, but that in no way means “intermittent fasting is awesome because autophagy.”  Autophagy isn’t awesome like that.

Alternate title: The dark side of autophagy.

For example: Autophagy contributes to muscle wasting in cancer cachexia (Penna et al., 2013)

Cachexia (muscle wasting) is one of the leading contributors to poor quality of life in cancer patients.  Thanks, autophagy.

“Autophagy is the major process for degradation of cellular constituents, its rate being enhanced under stress conditions leading to organelle damage…”

 

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Autophagy

Caloric restriction (CR) activates autophagy.  Intermittent fasting (IF) is basically kind-of-like the opposite of CR.  I’m not knocking IF.  The animal studies of autophagy, based on “chronic nutrition depletion,” more accurately reflect CR which results in decreased body weight or metabolic rate.   IF generally includes refeeds, resulting in weight maintenance.  Also, in the few human studies on it, weight loss (CR) but not fasting (IF) has been shown to induce autophagy.

If you’re actually losing weight over the long-term with an IF protocol, and thus are CR by definition, then I suspect you may be autophaging, too (yeah yeah, I know, that’s not really how autophagy works, but you get the picture).

Disclaimer: I’m relatively autophagy-agnostic; not really confident racing to maximize it is a great thing based on Human Studies.

Book: Autophagy in Health and Disease

 

autophagy-image

 

Exhibit A: autophagy in skeletal muscle

Tl;dr: “a little exercise is a better than a lot of fasting”

A1) Physical exercise increases autophagic signaling through ULK1 in human skeletal muscle (Moller et al., 2015)

The protocol: participants either fasted for 36 hours or received a glucose infusion before and during exercise (cycling at 50% max for an hour).

“In the present study, we demonstrate that short-term aerobic exercise activates autophagic signaling through ULK1 in human skeletal muscle, independently of nutrient background.”

They really should’ve stressed that the deck was stacked to show fasting activated autophagy… 36 hours of fasting is pretty long but it had no effect.

 

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Keto myths & facts

:::begin rant:::

Trigger warning?  Maybe.

Disclaimer: I’m pro-LC (P<0.05), but not anti-LF because LF works better than LC for some people.  And with the exception of things like keto for neurological issues, I think macros take a back seat to many other factors.

Myths: carbs cause insulin resistance (IR), diabetes, and metabolic syndrome.  Carbs are intrinsically pathogenic.  If a healthy person eats carbs, eventually they’ll get sick.

And the only prescription is more keto.

cowbell

And of course all of this could’ve been prevented if they keto’d from the get-go.

Proponents of these myths are referring to regular food carbs, not limited to things like Oreo Coolattas (which would be more acceptable, imo).  Taubes, Lustig, Attia, and many others have backed away from their anti-carb positions, yet the new brigade proceeds and has even upped the ante to include starvation.  Because “LC = effortless fasting?”

Does this sound sane?

“No carbs ever,
no food often…
otherwise diabetes.”

oreo-coolatta

no one in their right mind would say lentils & beans cause diabetes

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Ketones, carbs, and physical performance.

Or more specifically, ketone monoesters and carbs.  Literally, this study was a high-dose ketone monoester supp sans caloric or carb restriction.  I know, weird right?

 

Ketone ester

 

Non sequiter nutrition notes, #context, etc.:

1) ketone esters =/= ketone salts.  Ketone salts are either sodium or potassium-dominant.  Ketone esters are essentially salt-free.  Possibly helpful background reading here.

2) nutritional ketosis =/= starvation ketosis =/= ketone supp ketosis.  Because #context.

Starvation ketosis, but not nutritional ketosis, is muscle-sparing.  Ketone supps sans carb restriction might be.

3) the theory of ketone supps for sport is: 1) ketones are an energetically favorable fuel; and 2) they’ll spare glycogen, theoretically allowing prolonged duration of moderate-to-high intensity performance.  Adding in carbs will likely further this.

4) I have no studies to support this, but the idea of ketone supps in the #context of high carb doesn’t sit will with me.  Seems like high levels of both substrates = mitochondrial overload and oxidative stress.  Maybe.

5) there’s a gradient of fuel use during exercise:

-explosive power: creatine, anaerobic

-high intensity: glycogen, anaerobic

-low intensity: fatty acid oxidation, aerobic

But it’s a gradient with a lot of overlap, and ketoadaptation further blurs the lines.

 

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Long-term fat adaptation

Recent comments about FASTER have upgraded this study to “the only long-term study on fat-adaptation.”  Needless to say, I disagree.  Again.

Side note: FASTER had no randomization or intervention (ie, confounded by selection bias, among others); they basically recruited long-term low carb & high carb ultra-endurance runners and measured the stuffings out of ’em.

Ultimately, they showed a very high maximal fat oxidation rate in low carb ultra-runners, 1.5 grams per minute.  This is important because MAXIMAL HUMAN FAT BURNING CAPACITY

 

TROGDOR the BURNiNATOR

 

In previous studies on SAD (Standard Athletic Diet haha), maximal fat oxidation at similar VO2max% has been reported to be much lower, <1 g/min (eg, Hetlid et al., 2015 and Volek et al., 2016).

 

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Keto-Crossfit

Study: a handful of average-bodied Crossfitters in their mid-30’s were recruited and told to either: 1) keep doing what they’re doing; or 2) go full keto.  Crossfit 4x/week.   Strength testing before and after 6 weeks (Gregory et al., 2017).

I’ll start with the best part: KETOADAPTATION IS A REAL TRUE THING THAT WORKS (P<0.05).  Otherwise, this group’s performance would’ve plummeted.  It is known.

The performance test was time to complete a 500-meter row, 40 body weight squats, 30 abdominal mat sit-ups, 20 hand release pushups, and 10 pull-ups.

Tl;dr: both groups knocked about a half a minute off their time!

The key here is duration: 6 weeks of ketogenic dieting is adequate to restore performance back to baseline.  <3 weeks is not.

 

performance

 

Here’s the downside (sort of):

 

body comp

Basically, the keto group dropped carbs and failed to compensate by upping other calories.  I know I know, spontaneous ad lib appetite reduction, but this is a study on PHYSICAL PERFORMANCE.

 




 

And in further support of “muscle growth sans carbs,” keto dieters upped protein by 15% and this still wasn’t enough to compensate for the reduction in carbs/insulin: they still lost a bit of lean mass (NS).  Imagine if they hadn’t increased the brotein? yikes

 

food

 

so basically, they lost body fat because CICO and retained lean mass because exercise and protein haha jk

 

Admittedly, it was cool to see the body comp changes, but we know fat loss eventually plateaus and people start eating maintenance calories again (maybe a bit more if Ebbeling can be believed).  And this is where they remain for the rest of their lives (hopefully).  So at 6 weeks, they were still losing weight, nowhere near where they’re going to be for the rest of their lives, but THAT’s where I’d like to see performance testing (ie, at a stable body weight).  Don’t get me wrong, I hate myself in advance for making this critique: the researchers should’ve pushed more calories in the keto dieters bc this is a confounder in a study on PHYSICAL PERFORMANCE…  but this doesn’t really matter in the big scheme of things because Blackburn’s group did that and showed the results were the same haha

 

 

On another note, I don’t think people should expect an additional performance boost from being more ketoadapted (or more fat-adapted or whatever), primarily because whether the study is 3 weeks or 6, performance never really gets better than baseline in experienced athletes.  With more advanced training techniques, sure (and I think this is common), but not more keto- or fat-adaptation.

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calories proper

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Muscle growth sans carbs

1.  net muscle growth = synthesis – breakdown

2.  need =/= optimization

3.  #context

 

muscle sans carbs

 

I’m totally cool with keto, honestly!  but still don’t really like seeing stuff like the above graphic and people interpreting it to mean “KETO IS MUSCLE-SPARING.”

 

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Cyclical ketosis, glycogen depletion, and nutrient partitioning

Meal & exercise timing in the contexts of “damage control” and nutrient partitioning are frequent topics on this blog.  I generally opt for a pre-workout meal, but nutrient timing hasn’t panned out very well in the literature.  That’s probably why I’m open to the idea of resistance exercise in the fasted state.  A lot of pseudoscientific arguments can be made for both fed and fasted exercise, and since a few blog posts have already been dedicated to the former, this one will focus on the latter.

The pseudoscience explanation is something like this: since fatty acids are elevated when fasting, exercise in this condition will burn more fat; and chronically doing so will increase mitochondria #.  The lack of dietary carbs might enhance exercise-induced glycogen depletion, which itself would bias more post-workout calories toward glycogen synthesis / supercompensation.  Much of this is actually true, but has really only been validated for endurance training (eg, Stannard 2010, Van Proeyen 2011, & Trabelsi 2012; but not here Paoli 2011)… and the few times it’s been studied in the context of resistance exercise, no effect (eg, Moore 2007 & Trabelsi 2013).  However, there are some pretty interesting tidbits (beyond the pseudoscience) which suggest how/why it might work, in the right context.

Exercising fasted or fed for fat loss?  Influence of food intake on RER and EPOC after a bout of endurance training (Paoli et al., 2011)

John Kiefer, an advocate of resistance exercise in the fasted state, mentioned: “the sympathetic nervous system responds quicker to fasted-exercise. You release adrenaline faster. Your body is more sensitive particularly to the fat burning properties of adrenaline and you get bigger rushes of adrenaline.”

Much of this is spot on.  That is, ketogenic dieting and glycogen depletion increase exercise-induced sympathetic activation and fat oxidation (eg, Jansson 1982, Langfort 1996, & Weltan 1998).

The question is: can this improve nutrient partitioning and physical performance?  Magic 8-Ball says: “Signs point to yes.”  I concur.

Contrary to popular beliefs, glycogen depletion per se doesn’t harm many aspects of physical performance.  A lot of fuel systems are at play; you don’t need a full tank of glycogen.

Effect of low-carbohydrate-ketogenic diet on metabolic and hormonal responses to graded exercise in men (Langfort et al., 1996)

High-intensity exercise performance is not impaired by low intramuscular glycogen (Symons & Jacobs, 1989)

Increased fat oxidation compensates for reduced glycogen at lower exercise intensities (eg, Zderic 2004), and ketoadaptation may do the same at higher intensities.

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Carb Back-Loading and the Circadian Regulation of Metabolism

Carb Back-Loading (CBL) redux, part I

Step 1: eat little in the morning (maybe some fat+protein; definitely no carb)
Step 2: exercise in the afternoon/evening
Step 3: eat the carbs, all of them.  Preferably high glycemic carbs.
Other: no dietary fat post-workout; protein periodically throughout the day.

What makes CBL different from its predecessors is the stress on the timing – exercise and carbs in the evening.  John Berardi’s “Massive Eating” dietary guidelines are similar: protein+fat meals all day except pre- and post-workout, which are protein+carb meals.  Martin Berkan’s “LeanGains” is fasting most of the time (including pre-workout), exercise in the afternoon, then a big post-workout meal (quite similar to CBL).  My only tweak, as discussed below (and previously here and here), would be a pre- rather than post-workout meal [in some contexts].

There’s a summary of this blog post at the bottom… it might be helpful to read that first (see: “Tl;dr:”).  Also, please note that much of this post is about the fringe of theoretically optimizing nutrient partitioning, like improving from 85 to 90%, or 40 to 45%, not 40 to 90%…  I’m not that deluded.

My initial take, in general, is that this book is loaded with gems about nutrition, exercise, biochemistry, and physiology.  It’s also very readable and has a lot of good recommendations.  In this post, I want to discuss one specific aspect of CBL: tissue-specific circadian regulation of metabolism.

 

nutrient timing

 

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