Can grains and legumes be eaten at separate meals to get their full protein complement?

July 30, 2012 8:09 PM

I don't eat a lot of meat. I'm always combining grains and legumes because their combination gives you the protein your body needs. In his new book "Eat & Run," ultramarathoner Scott Jurek says you can eat, for instance rice at one meal and beans at another and still get all the protein. In other words, they don't have to be consumed at the same meal. I don't have any reason to doubt Mr. Jurek but I'm just double-checking, is this true? Thank you.
posted by holdenjordahl to food & drink (10 answers total)

That's my understanding.
posted by J. Wilson at 8:11 PM on July 30, 2012

Yeah I don't think the protein comes from some specific reaction that happens when beans and rice are digested at the same time. Just comes from rice and/or beans.
posted by TheRedArmy at 8:12 PM on July 30, 2012 [3 favorites]

My understanding is that protein combining went out fairly early - Frances Moore Lappé's "Diet for a Small Planet" was the most famous proponent of food combining, but later editions of the same book acknowledged that it was not necessary to have all the amino acids at the one meal. See here.
posted by Cheese Monster at 8:14 PM on July 30, 2012 [5 favorites]

Incomplete proteins don't have to be eaten together to make a complete protein.

Your body doesn't know what a meal is -- that's a cultural construct.
posted by Sara C. at 8:14 PM on July 30, 2012 [8 favorites]

Yes - and depending on what you are doing it might benefit you to eat a small carb-heavy meal at one time of the day and then later a more protein-heavy

Also soy (a legume) is a complete protein, so if you're eating that you're ok.
posted by Lt. Bunny Wigglesworth at 8:23 PM on July 30, 2012

Thanks, everyone!
posted by holdenjordahl at 8:27 PM on July 30, 2012

animal proteins are made out of 21 different amino acids, but not all proteins are made out of all 21. So if rice has 11 and beans have the other ten (i'm guessing there's overlap), then you're fine. miss out on even one of them for any length of time and you're not going to feel so hot.
your body breaks down proteins into amino acids which it uses to make it's own proteins (including the enzymes that break down the original proteins), so if the protein supply isn't 'complete', you can't make the ones you need to survive.
also, there's a bunch of places on earth (islands in particular) where the protein supply isn't complete...including Hawaii IIRC...
posted by sexyrobot at 8:57 PM on July 30, 2012 [1 favorite]

but yeah...you don't need them all at the very same instant...and some amino acids (and thus the proteins that contain them) are less vital than others and dont need to be eaten as often...in general adults don't need as much protein as growing children...
posted by sexyrobot at 9:00 PM on July 30, 2012

One of my favourite blogs, Sweat Science, dealt with this very issue in a recent entry.
posted by smoke at 9:38 PM on July 30, 2012 [2 favorites]

Soy is technically a complete protein, but its methionine content is quite low. If you want a complete protein, try quinoa.
posted by It's Never Lurgi at 9:48 PM on July 30, 2012 [4 favorites]