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What is the benefit of L-Leucine supplementation?

I've been reading about it, but I keep hitting a conceptual wall - if BCAAs contain the 3 top essential amino acids, why would an overload of one of them (even the most important) have any effect?

Taking it still further, why would BCAAs help? If I need all of the essential amino acids to gain muscle (or stave off loss), wouldn't I need all of them at once each time any was needed?

I'm currently on a calorie-restricted diet, but sufficient protein (my lowest days are over 1g/pound of LBM). I've been thinking about possibly supplementing with BCAAs or L-Leucine to ensure I have sufficient quality protein no matter what my meal. But I keep hitting that conceptual wall - wouldn't just taking some whey protein or casein protein have the same or better effect? 5g of BCAAs is 5g of protein, it's just concentrated around a subset of animo acids. L-Leucine even more so. I used BCAAs successfully when I was in Japan in the hospital, but that was because I didn't know that I'd have space for a big honking bag of protein so I wanted something portable...now that's no concern.

What do you think guys, worth it? Regular protein a better choice even when cutting weight and restricting intake?

Well from a purely biomechnical perspective it makes sense that it could work. The cell DNA processes can only do so much simultaneously, so an overload of only the things you want could be better. I've seen articles similar to http://www.pponline.co.uk/encyc/0336.htm in various fitness magazines forever.

That said, I haven't actually tried overloading BCAAs.

I just cycled off 2 months creatine (which I've never noticed really doing anything) so this might be a good time to try overloading BCAAs for me too... :-/

Edit: actually I did take "GNC Wheyabolic Extreme 60" a long time ago. But I took it somewhat randomly, and my routine wasn't as stable as it is now, so I can't comment on effectiveness.

Pete,
The way I understand it, you have the right understanding of BCAA. You don't need them if you are getting enough protein. Having said that, I do keep a bottle in my bag. If I forget my protein or don't have a bottle to mix it with, I take them after a training session.

Peter, you're hit the nail squarely on the head. If you were running a car factory, and you had all your parts and supplies in adequate quantities, you wouldn't think that you could increase production by ordering extra spark plugs. Amino acids that are out of proportion to your needs are wasted. If they are expensive amino acids, then your money is wasted as well.

Well except that for example, per that link, you might benefit from extra spark plugs, since the seat cushions are currently holding some of the spark plugs hostage and trying to convince you to come take a nap in exchange for getting them back.

This is debated quite a bit but I they are useless especially with how high in protein peoples diets tend to be. This is assuming the person doesn't live in a third world country and isn't a retarded vegetarian.

Okay, so as long as I'm getting sufficient protein with my meals, it's probably unnecessary for the reasons I mentioned in my earlier post. That's fine. I'm eating a minimum of 1g per pound of LBM of protein a day, almost all of it complete in and of itself or made complete through food combos. So it's not likely BCAAs and L-Leucine are going to be worth the cash at this point.

And ironmaiden, I understand you have strong feelings on the subject, but several members of my immediate family are vegetarian. I'd rather not have their eating habits make them subject to insult.

No insult was intended, I was referring to vegetarians who do not practice it the correct way. Since there is no plant with a complete protein source some of them do not get the full array of AA's in their diet hence can have potential adverse health effects. Then there's the whole issue where some of them who again do not diet correctly and have low protein levels in the body causing much worse health effects. No issues with vegetarianism just people who don't do it right.

Should have explained what I meant by retarded vegetarians and apologize if I did offend you.

Okay, I thought you were referring to all vegetarians.

No worries.

I looked at my ON Whey last night - 2 scoops is already 10g BCAA. And I do 2 scoops pre and post workout. So... dunno... might add some more, but seems like I'm already getting a lot.

Right. Though AFAIK those BCAA calculations are just the amount of those 3 amino acids you get in the scoop, not "extra" over and above. Which is fine with me.

I'm pretty sure I use the same ON as you - ON Gold Standard 100% Whey, right?

Correct, and yes.

Seemingly the claim is that the most useful AAs are the BCAAs and Glutimine - by that standard it looks like "Isopure Zero Carb" is the winner. The profile would be similar to combining 50g of ON Whey with 5g BCAA - and the price would be similar as well.

How can any AAs be "most useful"? If one of the other essential AAs is missing the rest are useless.

I always assumed it was because the rest are more readily available, and/or because the BCAAs are needed (or can be effectively utilized) in disproportionate amounts.

I could be wrong - I asked originally because I don't really know!

That's what I'm trying to understand. These people spend tons of money on bcaas because they are suppose to be the most anabolic of all AAs and are comprised of approx 1/3 of all muscle. But from my understanding you need high amounts of all AAs or protein synthesis will stop. Also a good chunk of protein powders have already 5-10g of bcaas so why supplement with more?