So some nuance (because we love that here)
There are two angles I see this question needs to be addressed from. First, what a particular individual’s leucine needs are to maximize MPS. Second would be sourcing that leucine.
How much Leucine is needed for an individual to initiate maximized MPS is dependent on their age, training status, energy status (protein needs and calorie restriction were covered in TBaB which you have read), size, and sex. In one of the nutrition seminars, the Drs said that an untrained geriatric will typically need twice as much leucine to initiate MPS, but if they were to begin training, that double dose need actually goes away almost entirely within a few weeks (I think they said weeks).
As for size and sex, let me quote Jordan’s article 7 rules to optimize protein intake: (7RtOPI)
The more male someone becomes, the more sensitive to amino acids they are, in general. This would allow a male to need slightly less protein per pound than a weight and age-matched female. That being said, lean body mass weight also plays a role in the amount of leucine needed per meal to maximize MPS, but this is literally a variation of 0.5-1g tops for a range of bodyweights between 100lbs-300lbs, so we don’t take it into consideration and 3-4g is very safe.
One more data point on the Leucine requirements for an individual. I can’t quickly find a BBM reference to this, but much of the literature uses 2.5g of leucine as the threshold for non untrained geriatrics. it is my understanding that BBM’s standard 3-4g is rounding up to account for a broader populace that may include those that need more than the standard 2.5g because they are calorie restricted, huge, untrained, geriatric, who knows.
So depending on information that I don’t know about you, and that I’m not necessarily qualified to evaluate anyways, the 2.5g standard may be more applicable to you as an individual.
Ok, all that out of the way, what can you do about what you eat? (which kinda addresses your last question)
Well, if you really want to work hard to get that recommended large dose of Leucine 3-5x a day in your smaller calorie requirements, the generic “animal based protein” recommendation might not be specific enough to accomplish this. First, let me quote another line from the 7RtOPI article.
This is also, of course, assuming that the protein you’re consuming either contains all the essential amino acids (like all animal derived proteins do) or you have eaten a protein rich meal within the past 4-6 hours that had all of the EAA’s present in abundant amounts.
So if you have eaten sufficient quality protein with, or within 4-6 hours of eating leucine with the intent of initiating MPS, you could go with a BCAA supplement like Jordan’s Peri-Rx (4g Leucine per serving) or Scivation’s Xtend which Jordan has in the past said doesn’t really count towards macros (but I do log them in as protein). Alternately, you could supplement a meal with EAA’s in it but not quite enough Leucine, with one of those BCAA supplements or some whey, which if it’s quality whey will have a huge amount of Leucine per gram, and has all those other EAAs anyways. (it takes about 29g of beef protein to hit 2.5g Leucine, but only 20g of protein from Jordan’s Whey-Rx’s to get 3g)
Unfortunately, I don’t have a spreadsheet that explains exactly how much of each EAA is in that tofu and beans, compared to what constitutes “EAA’s present in abundant amounts.” That’s actually information I really wish I had.
One final note: The Drs say just hitting the quality daily protein requirements without hitting the recommended Leucine protein timing recommendations gets you 90% efficacy, and the MPS maximizing strategy just gets you the extra 10%. So NBD if you can’t get it perfect.
