Protein, how good are beans and quinoa?

We are often recommended to eat protein from plant sources instead of animals. Vegan advocates tell us you can get all the protein you need from plant sources. I don’t have a problem with plant protein, but is it really a good source of high quality protein?

My current hobby is powerlifting – and I find a certain amount of protein makes all the difference to my strength gains and recovery (as well as satiety). My first intro to adequate protein was through Barry Sears Zone diet, when I increased from a fairly low level to around 1.6 grams per kg per day, and around 20 grams per meal. Since I’ve been lifting heavier weights over the last year – I’ve experimented with 2 to 2.2 grams per kg per day and not less than 30 grams net at each meal.

One person who has been influential for me from way back it Dr Donald Layman, in this video – he recommends 30 grams per meal per day, so I’ve been doing this now for some time.

Here is Dr Layman’s lecture by the way – well worth a watch.

30 grams net protein – how much food / both calories and weight does it take to reach this amount?

I’ve put a little graph together for you.

Quinoa – well, now you know – it takes 680 grams of cooked quinoa to reach 30 grams of protein, and this would give you a whopping 816 calories. Lentils and beans are better sources of plant protein, however you will notice that both have more carbohydrates than protein, so a meal of kidney beans or lentils won’t really need additional carbs in my view, and would be best accompanied by non starch vegetables only.

And what about nuts? They give a decent amount of protein, but the main macronutrient they contain is fat. So to reach adequate protein you end up with a lot of fat.

Cheese and very fatty meat (like pork belly and bacon) can also be a problem because you may end up with too many fat calories, not great if you are looking to burn off your own fat, rather than store more. Some of the low carb high-fat meals I see recipes for, might be doing you a disservice if losing fat is your goal, here is one example:

Keto Bacon and Eggs

Three meals a day with this amount of fat, even with low carbs would see me stacking it in my fat stores. You might be a fat burner with this meal – but it won’t be your own fat you are burning it will be ingested fat, and any you don’t use for energy needs will go straight to your fat cells.

Another factor we need to take into account is Protein digestibility-corrected amino acid score (PDCAAS) this is a method of evaluating the protein quality based on both the amino acid requirements of humans and their ability to digest it. The PDCAAS rating was adopted by the US Food and Drug Administration (FDA) and the Food and Agricultural Organization of the United Nations/World Health Organization (FAO/WHO) in 1993 as “the preferred ‘best'” method to determine protein quality.^[1]

So what are the PDCAAS of different proteins? Wikipedia has a nice little chart (link here for the full chart and links to references)

Our animal protein scores are high, but they decrease as you get to the legumes, lentils, and peanuts. So even though 115 grams of peanuts contains 30 grams of protein, your body will end up with just 52% of that, making it a poor source of protein.

If you do follow a diet free of animal protein, you might consider supplementing your diet with pea protein isolate or Sacha Inchi powder to get the protein you need to maximise muscle maintenance and growth. Mycoprotein (Quorn) a prtoein processed from fungus is also a good choice. (New Zealand website here)