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NortonI had not heard of Dr Norton before...
Two of Norton's defining areas of research are on...
1) Leucine: This amino acid activates mTOR (Mammalian Target of Rapamycin). mTOR triggers muscle growth when the right amount is consumed at the right time.
The Right Amount
Between 2.5 - 4.5 grams needs to be consume during a meal.
Higher quality protein are dairy and meats. Approximately 8% is composed of Leucine.
Whey Protein contains the highest percentage, between 10 - 12%. That along with how quickly it is digested is why Whey is often referred to as the Anabolic Protein.
Vegetable Proteins are low in Leucine and protein quality.
As an example, you'd need to consume two cups of bean and rice get close to the right amount of what you need. That is one of the downsides of the Vegan Diet.
One of the solutions for someone on a Vegan Diet is to supplement (add Leucine) to the meal.
Added leucine makes wheat protein as anabolic as whey
Wheat protein is a low quality protein with a low Leucine content.
Norton's research found spiking Wheat Protein with Leucine eliminated that issue.
The Age Factor
Younger individual need about 2.5 gram of Leucine per meal to trigger mTOR.
Older individual need over 3.0 gram of Leucine per to trigger mTOR.
Younger individual's system are much more efficient that older individuals. Thus, the reason for the difference.
2) Refractory Period
Norton, along with other researchers, determined that a certain amount of time between protein feedings optimized protein synthesis, mTOR.
They determined that consuming a meal every 4 - 6 maximized protein synthesis. The dogma of eating every three hours is less effective.
Think of the Protein Refractory Period like let's say heavy Squat Training. A heavy "Squat Refractory Period" (the amount of time between training sessions) is at least 48 hours.
The same is true with "Medication Refractory Periods". Some medications are prescribed once or twice a day. Taking them more often is counter productive.
Dr Donald Layman
Layman worked with Norton on the Leucine research.
Layman research determined that the majority of individual only consume enough protein (Leucine) at dinner. The amount of protein consumed at breakfast and lunch are not enough to trigger mTOR.
That is one of the reason that as most individual age, they lose muscle mass. Only consuming one "Anabolic Meal" a day isn't enough to maintain muscle mass, let along increase it.
Between Meal Protein Snacks
Research shows this dogma is counter productive. However, it continues to be perpetuated.
However, based on Norton's research it appears that consuming the supplement Leucine or Branch Chain Amino Acids approximately 1.5 hour after and 1.5 before is effective at triggering mTOR.
Additional research indicates when Leucine is taken with a 6 grams of a quickly, anabolic, complete proteins such as Whey; protein synthesis (the anabolic effect) is enhance even more.