Matt Metzgar

A Feast/Fast Model for Muscle Growth

Here is a simple framework that offers the potential to build muscle without increasing body fat.  The cycle starts on the day of a planned resistance training session.  It would seem logical that a person should somewhat undereat prior to the exercise session.  This is done for two reasons:

• When an animal or hunter-gatherer runs low on food, this is the logical time when they would begin a new hunt (workout)
• By fasting or eating less prior a workout, this will help increase hunger after the workout, which would then allow for more food intake in this crucial period

After the workout, there is a roughly 24-hour window where most or even all of the calories are going to muscle repair and growth.  With sufficient calories, the muscle repairs itself but does not rebuild.  With a calorie surplus, new muscle mass is created.

I think a shorter post-workout window for muscle growth makes sense from an evolutionary perspective.  If a person undergoes a strenuous hunt/workout, then it would make sense that the body would want to react to this stressor and remodel itself as soon as possible.  This is in case the stressor comes again sooner than later.

If this model is correct, then here is what I think is happening with traditional "bulking" cycles.  A person works out and breaks down muscle tissue.  If they have a calorie surplus in the next 24 hours, they build muscle.  After this, the post-workout window is closed.  If they continue to eat a calorie surplus after this period, they also build muscle, but this is simply muscle built via general overfeeding and part of this overfeeding will go to fat storage.

So in summary, here's the simple model I'm proposing:

• Undereat or fast before a workout
• Resistance train to break down muscle
• Run a calorie surplus during the post-workout window to create new muscle
• Return to normal eating (intake = expenditure) after the 24 hour window
• Net result: muscle gain without fat gain

This would be compared to a traditional bodybuilding model:

• Eat or overeat before a workout
• Resistance train to break down muscle tissue
• Run a calorie surplus during the post-workout window to create new muscle
• Continue to run a calorie surplus after the window has closed
• This overfeeding after the window has closed will lead to both muscle and fat gain
• Net result: muscle gain with fat gain

More to come on this...

Does Gorging Equal Muscle Growth?

Many wild animals, particularly carnivores, exhibit a feast/fast eating pattern.  I have been looking into how this may connect with muscle growth.

The first thing I'm noticing is that the "window" for muscle growth may be shorter than people think.  This new study shows that protein synthesis rates were back to normal only 28 hours after a resistance training session.  Other studies suggest that protein synthesis is only elevated 24 to 36 hours post-workout.  How long this window lasts can be affected by various factors, but it does seem to be a relatively short period of time.

From this, I think you can make a simple connection to overfeeding.  We know a calorie surplus is needed to build muscle.  If you just simply overfeed when sedentary about half goes to muscle and half goes to fat.  If you overfeed post-workout, it would seem like the lion's share (pun intended) of calories would go to muscle.

Here's another clue: a feast/fast eating pattern helps maintain muscle mass in men with HIV-related wasting.

Meals and Muscles

From a pure calorie point of view, you need a calorie surplus to build substantial muscle tissue.  I am of the opinion that you shouldn't have to force-feed calories to do this.  I've been looking into the issue of meal frequency, and I've come across some good research on the subject.

This study notes that there is an inverse relationship between meal frequency and body weight.  In other words, those who eat fewer meals weigh more than those who eat more frequent meals.  I dug further and found this has been verified by other research.  Here's a key chart from this study:

In men, those who habitually ate fewer meals actually consumed more toal calories!  If you convert the MJs to calories, those who ate 2 or 3 meals a day consumed about 250 more calories per day than those who ate 6 to 8 times per day.

Therefore, if you're looking to build muscle, and you naturally want to increase your food intake, one way to do this is to eat fewer meals.  Reading the paper, it appears that waiting longer between meals increases hunger more, such that a person tends to "overshoot" and consume more calories.  In fact, the study shows that those who consumed many meals per day were better at matching energy intake with energy expenditure.  This is not a good thing if you are trying to build muscle, since you want to create a calorie surplus.

All this is very surprising and somewhat counter-intuitive.  It's easy to think that eating more often would lead to greater total calories consumed, but instead it's the opposite.

Overfeeding

I've been looking into overfeeding, as I ultimately want to see how this interacts with resistance training.  One of the first things I found is that with any type of overfeeding, regardless of exercise, some of the excess goes to lean tissue and some goes to fat.  This is intriguing to me, because you might figure that all the extra calories would go to fat.

Second, I've found that your starting point makes a difference as far as the effects of overfeeding.  This study looks at the differences in overfeeding in lean versus obese subjects.  In short, wtih obese subjects the extra calories were more likely to go to fat.

This same study also looked at the effects of excess carbohydrate versus excess fat.  The results showed that excess fat was more likely to be turned into bodyfat than excess carbohydrates.  But I think this relationship might be altered when exercise, specifically reistance training, is added to the equation.  Also, even though the excess carbohydrates led to less fat, it almost doubled fasting insulin levels. 

The connection with insulin also seems to be mediated by time.  This study shows that insulin action is mostly unaffected in short-term overfeeding.  So it may be that continual overfeeding that leads to higher insulin levels, and shorter cycles do not.

As far as how excess calories are split between lean tissue and fat tissue, the ratio seems to about 50/50 in healthy individuals given no real exercise component.  This is a good study(pdf) that tracks weight and other measures when subjects underwent overfeeding.

So the question becomes, can you get the ratio to 100 to zero, or all lean tissue gain with no fat gain?  I'm working on it...

Barefoot Running Technique

The other week I was running on the track at the gym.  I usually try to follow the Pose technique of running, landing under the center of gravity with a tempo of 180 steps per minute.  But for some reason, the run just didn't feel right and I couldn't get everything to "click".

In frustration, I kicked off my shoes and ran in just socks.  Almost immediately, my form improved - my turnover increased and my landing was in better alignment.  It seemed that by letting my body feel the true impact of each step via barefoot running, my technique self-adjusted and became more efficient.

I already wear minimal shoes, the Puma H Street.  But this stretch of barefoot running felt even better.  Since this experience, the last two times I ran, I just ditched the shoes from the start and ran the whole time in socks.  I felt no ill effects from doing this, running 20+ minutes each time.  My feet were fine after the run and fine the next day.  Shoes, who needs 'em?

Stone Age Self-Help

Here's an article(pdf) about a "Stone Age" approach to depression.  The author believes there are six key to treating depression in the modern world:

• Sufficient sleep
• Omega-3 fats
• Aerobic exercise
• Sunlight exposure
• Socialization
• Less rumination

Some newer studies show this combination may be as effective as traditional treatment (i.e. drugs).  A recent analysis(pdf) of this technique tried to find out which part was the most potent, with less rumination coming out as the only significant variable.  But at the very least, this type of common-sense program is a solid basis for treating mental health issues with evoutionary insights.

The Relationship Between Size and Strength II

In this last post, I discussed the relationship between muscle strength and size.  First off, it is possible to lift heavy weights without gaining much size.  This is because the relationship between the two is mediated by two main factors:

• Total volume of resistance training
• Calorie intake

The volume of resistance training is crucial for increasing muscle size, because more volume leads to more muscle protein breakdown, which can lead to more muscle growth. 

But here's an easier way to put it: when I look around the gym, the people who have more muscle than I do are lifting heavier weights than me.  But the key is they are lifting these heavier weights for multiple reps and sets.  They are not coming in, doing a couple of heavy singles and then hitting the showers.

For example, I was doing some deadlifts at the gym this week, working in with this other guy.  He had a good amount of muscle for his size - I'm guessing he was 5'10" and weighed between 200 and 210 pounds.  I asked him how much he could deadlfit (max), and he said 375 lbs.  But compare this to the person from "Bearpowered" I showed in the previous post, who could deadllift 440 lbs but only weighed 144 lbs. 

We proceeded with the deadlifting workout, and he did a traditional pyramid type workout, doing 5 sets where he went up in weight and down in reps.  And this helps illustrate where there can be a disconnect between size and strength: a person may be able to get strong via infrequent, low-volume, low-repetition lifting, but this strength is mostly just neurological improvements, not any increase in the cross-sectional area of the muscle.

There are some technical parts to this idea, such as the "central governor" theory and such, that I won't get into at this point.  But a story might be a better example.  We've probably all heard a story like this: a person in a life-or-death situation lifts an incredible amount of weight in order to save someone's life.  Assuming such stories are true, where do these people who normally can't lift such weights get the "strength" to lift such massive amounts?  The answer is that the physical potential has always been inherently there, but there was never any reason for the central nervous system to "lower its defenses" and allow the person to lift the weight. 

In this sense, infrequent powerlifting-type regimens primarily train the central nervous system, and do not really lead to much muscle hypertrophy.  And this is where I think people need to be more specific when it comes to what they're after in regards to strength training.  Does a person want to be able to just lift heavy weights, or do they want to do it in such a way that they also end up with more muscle mass?

For example, I've seen it written many times where "3 sets of 8-10 repetitions are optimal for increasing strength".  Really?  Not if you are talking about a maximum lift (1 repetition max).  If I had one month to increase my 1-rep max in an exercise, one of the last things I would is 3 sets of 10 with a sub-maximal weight.  Instead, I would be doing heavy singles, partial reps with heavy weight, static holds and negatives with weights greater than my current 1-rep max, etc.  These are what would really boost the strength levels via neurological improvements, at least in the short term.

To be continued...    

Thoughts on Fasting

I've written before about intermittent fasting and its benefits.  I think it's an essential piece to the overall puzzle, but it doesn't seem like the general thinking on the subject is complete.

For example, you can perform intermittent fasting by creating a compressed eating window.  If you normally take in 3,000 calories a day spread over six meals, you can instead compress that into say two big meals during a shortened time frame.  This may be beneficial and lead to improved health outcomes, but it seems somewhat artificial to me.  It doesn't tie fasting to any larger, overall eating pattern.

The real question is: why would a hunter-gatherer engage in intermittent fasting, that is, not eat for a period of time?  I can only come up with two main reasons:

1. They aren't hungry.
2. There is no food left.

And both of these are tied to the overall feeding or hunting cycle.  If they aren't hungry, it's probably because they've just had a period of good eating.  And if there's no food left, then they are most likely getting ready to look for new food, or are already in the process of searching for new food.

I've been researching the feeding cycles of animals, and here's a good paper on the subject.  Here's the first sentence from the abstract:

"Food intakes of wild animals may not match their requirements for nutrients and energy but may vary between periods of nutritional excess (hyperphagia) and nutritional deficit (hypophagia) at timescales that vary from days to months."

One part of the paper also addressed how feeding cycles relate to meals.  Here's the quote:

"Excess intakes are associated with more frequent or larger meals that infer a positive relationship between daily excess and maximum digesta fill."

So it appears that meal frequency and size is dictated by the feeding cycle: when there is excess, there are more frequent or larger meals.  On the other end of the spectrum, when there is a deficit there are fewer or smaller meals.  Intermittent fasting represents the far end of this spectrum, with no food and zero number of meals.

Eating, Hunger, and Growth

I wanted to post about what would look like a contradiction: in this post, I said to eat when hungry but in this post I talked about how I will have to eat more in order to gain muscle.

After thinking about it more, what I really meant to say is that I needed to eat more such that thermodynamically I'm taking in more than I expend, but that this surplus should be driven by hunger.  This takes a little more explanation.  Here's how Taubes presented the first law of thermodynamics in his book:

Change in energy stores = Energy intake - Energy expenditure

And here's a corresponding quote about growth in children from the book: "Children do not grow because they eat voraciously; rather, they eat voraciously because they are growing.  They require the excess calories to satisfy the requirements of growth; the result is positive energy balance.  The growth is induced by hormones and in particular, by growth hormone."

So if a person is lifting weights and not gaining weight/muscle, then here's some points of speculation as to what's happening:

1)  The workouts are not properly releasing growth hormone.  Maybe there's not enough intensity or volume, or perhaps overall it was too taxing.

2) A person is doing too much overall endurance exercise.  This is suspected to lower growth hormone (and testosterone) levels.

3) The growth hormone and corresponding hunger after the workout is blocked.  For example, if you eat simple carbs after a workout this supposedly shuts down growth hormone relase.  I'm not 100% sure this is true yet, but let's assume this is true for now.  If simple carbs are eaten after a workout and growth hormone is blocked, then the corresponding hunger is blocked, hunger which would have led to increased protein and fat consumption.  So without the post-workout carbs, maybe you have raging hunger and feasting on protein and fat.  With post-workout carbs, you shut down this process.

4)  Overall eating patterns are incorrect.  We know that intermittent fasting increases growth hormone.  So if there are no fasting periods in a person's normal eating pattern, they may be missing these growth hormone bursts, which may help to increase hunger.

5)  Food composition.  Let's say a hunter-gatherer was eating meat.  If the meat was 30% fat instead of 20% fat, would he necessarily eat any less meat?  In the modern world with all the low-fat preaching, people's tastes may not be used to high-fat meat.  So fat consumption may be indirectly limited just by traditions and cultural forces.

These are all just educated guesses on my part, but I do think they are valid points.  I do not think a person should have to force-feed food in order to build muscle.  It's probably just a matter of setting up things correctly, allowing the growth hormone to drive hunger, then consuming the proper foods, which will naturally lead to a calorie surplus and some new muscle.   

Mr. Roboto

After the last post on feeding cycles, I started thinking about how many modern nutritional prescriptions are off the mark.  For example, you have many people recommend six meals a day, each one "balanced", and total calories the same day after day.  How un-naturalistic can you get??

It's like people are thinking about how to feed a machine instead of an organism.  Sometime people recommend "variety" in a diet, but this is mostly lip service.  Decrease calories one day a week?  Why, what for?  Instead, it should be connected to an overall context of the feeding cycle.

For example, here's a scenario for a hunter: he wakes up in the morning, and he is out of food and getting hungry.  So he commences with intense physical effort to acquire game.  If he's fortunate, he scores some game; if not the hunt continues, maybe stretching out another day.  After acquiring game, maybe he feasts immediately or instead he waits until he brings it back to camp.  Next there is a night and perhaps a day or two of relative relaxation and good eating.  Then food starts to run short and the whole cycle begins again.

Within this type of scenario, you might have many things happening: calorie-wise, there might be a deficit on the initial hunting day(s), a surplus for a day or two, and then another deficit day.  Meal-wise, you might have fewer meals on the hunting days and more meals on the feast days.  Meal composition-wise, you might have more carbs (plant food) on the deficit days and more meat on the surplus days.

But all of this would be a mixture and flow, nothing like a static amount of calories spread over six meals a day.  And judging from the lion study, a naturalistic eating pattern is what we're designed for.  Figuring out examples and a template for all this is difficult though.  Modern hunter-gatherer tribes have been pushed out to marginal areas, and so their feeding cycles may not be representative of our ancestors.  The best bet is to utilize the existing research, take some educated guesses, learn from experience and the experience of others, and try to build a more naturalistic eating pattern that is functional and healthy.