If mTor and ampk represent in a simplistic manner the fed and fasting states....or with fluctuations and waves of hormonal regulation, then, if seeking muscle growth it's not just about leucine in post exercising fueling but also using insulin to create greater mTor signalling, isn't it? With carbs.
Insulin Is Anabolic
Insulin is "Globally Anabolic". It does not discriminate.
It promotes muscle growth as well as an increase in body fat.
As per Jay Robb (nutritionist), "Insulin is a fat maker..."
Like Goldilocks, the key is finding what just right, as with everything.
Leucine Trigger Insulin
Leucine increase insulin production, although not to the same degree protein mixed with a high glucemic index carbohydrate (Dextros or Maltodextrin).
Whey Protein increases insulin production due it high content of Leucine: Leucine is 10% of Whey.
That means that Leucine, Branch Chain Amino Acids or Whey Protein appear to produce an anabolic effect for this reason.
Adding some high index carbohydrate to the mix bumps of the effect. Some experimentation is required to see what might be effective for you.
If then seeking balance, go with lower carb or none or no food to optimise ampk.
AMP-k
AMP-k and mTOR are on a See Saw. When one goes up the other goes down.
Yes, lowering carbohydrates, lower carbohydrates and no food ramp up AMP-k.
On A Side Note
1) High Intensity Resistance Training or HIIT Cardio Training turn on mTOR.
2) Endurance Training shut off mTOR and increase AMP-k.
Thus, someone who has an High Intensity Resistance Training Session and then follows it with Endurance Cardio has negated most of the anabolic muscle building effect of their Resistance Training.
Surely....if seeking optimum protein synthesis but not by using insulin/carb response and only leucine then you're not getting the optimum coveted response?
Questionable
As with most thing, it depends on the research data you're reading.
The data that I have indicates, Leucine is effective. Some research demonstrated a Whey Protein only beverage (no carbohydrates) was just as effective.
Due my metabolic condition, I am on the Ketogenic Diet. My training and recovery are fine with the use of Whey and Leucine.
However, it took me some time to figure out how to make it work. The Ketogenic Diet metaphorically speaking, turn thing upside down.
...mTor activated protein response will demand greater leucine?
Leucine Dosage and mTOR
The minimal dosage for younger individual to turn on mTOR is 2.5 gram of Leucine.
The minimal dosage for older individual to turn on mTOR is around 3.0 gram of Leucine.
The Minimal
Let think about it this way. Let say you make the minimal wage/amount of money to live how. That means at the end of every month you break even.
The same is true with true with Leucine. To get ahead you need to take more than the minimal about of Leucine.
My Leucine
Based on my age and my training I have dramatically increase my Leucine intake. My training session are going better.
My Leucine dosage with my meals is between 5 - 6 plus gram of Leucine. I spike my Whey Protein drinks that I have with a meal or consume a traditional meal and then have some Leucine.
I suspect that I my Leucine dosage may be higher than it should but since my workout are going better, I am reluctant to drop the dosage down.
As you said, "...mTor activated protein...in response will demand greater leucine..."
What I have learn is more is better. The question is, "How much more do I really need? Would 4 gram of Leucine work just as well?"
Leucine is ketogenic and it could be used for energy rather than protein synthesis.
Research indicate the Ketogenic Diet protects and spare Leucine from being used for fuel. Source:
The Art and Science of Low Carbohydrate Performance, Volek and Phinney
Additional research show that the amino acid, Alanine is converted to glucose, sparing Leucine.
.just eat some carbs after exercise if you want to optimise that pathway with your protein/leucine.
Try It
...and see how it work for you.
Kenny Croxdale