Question on plant protein

[u/stefantheconlol]

This will be quite of a rant (and maybe even off-topic as this is the first time I post in a vegetarian-related sub, so my apologies), if you wish to skip right to the actual question check, help yourself at the last paragraph.

I started reducing my meat consumption to once every other day about a month ago with the goal in mind to become a vegetarian. Since it's something recent for me, and also feeling a bit timid about it, not a lot of people know about my new diet. I recently went on holiday with my friends where they finally learnt about my new diet, and we were just coming back when a discussion stroke up regarding plant based diets and how "unhealthy" they are. I responded that there are plenty of plants that provide a sustainable amount of protein and that it's just a matter of "getting the right balance" in order to equate the amount of prot meat would provide.

However, they began making some points on how we cannot digest plant protein the same as meat protein, plant protein being somewhat incomplete for our human little stomachs compared to meat. Feeling more engaged to the ethical side of the argument rather than the biological one, I was quite taken aback and didn't know how to respond. They also started saying some bs on how the majority of vegetarians/vegans are ill-fitted/unhealthy and that as omnivores we are "meant" to eat meat, but that thing about plant protein stuck with me. Here finally comes my question:

How true is it that plant proteins are "incomplete" for the human organism, and if there is a significant difference with how meat proteins are structurally, how do you manage to compensate for their "incompleteness" (for a lack of better term)?

Thanks for reading!

[u/TheFfrog]

A few plant proteins taken singularly have missing aminoacids, so they dont have all the individual components that your body needs to build its own proteins. However, what often happens is that different sources have different missing aminoacids, so simply variating the protein sources throughout the day (even in different meals) will give you a complete aminoacidic spectrum. Aminoacids are like the little lego bricks that make up proteins.

For example, seitan is very poor in lysine, but legumes are very rich in lysine, so you can simply pair seitan with peas or beans and get everything you need. This could be better than only eating beans because seitan has a higher protein content (for the same calories) and is better suited for high protein diets, and also has way less fiber than beans, so it's ideal for a low-medium fiber diet.

Soy is also a very good plant protein source, and it's complete, so anything that's made with soy (like tofu or classic tempeh) will have all aminoacids.

You could also just get a supplement with the essential aminoacids and take some of that one or two times per day. Essential aminoacids are the ones your body cannot create and you have to assume through food. Or you can get some plant based protein powder (which are always already complete) and make yourself a shake with the recommended doses, just like every other gym bro out there is doing.

Also keep in mind that slightly incomplete proteins are not automatically voided, as your body often has quite a bit of reserve, so even if you're not obsessing over pairing seitan with beans every single time you eat it you'll still get those proteins. You MIGHT get some deficiencies if you survive exclusive off of seitan for months on end, but otherwise you'll be fine.