I don’t know if it’s just me, but I have been seeing a bunch of infographics such as these lately:
While the second one’s much better than the first (credit: Avery Muether Illustrations), it includes fairly accurate protein quantities (and some of these foods are reasonably high sources of protein), I still wanted to comment on them. I went through the foods included in the first infographic and looked up the protein in a serving of each. Here they are:
spirulina (1 tbsp dried) – 4g
goji berries (2 oz dried) – 8g
chia seeds (1 oz) – 4.4g
spinach (1 cup raw) – 0.9g
hemp seeds (2 tbsp) – 10g
barley grass (6g dried) – 1.5g
brazil nuts (1 oz) – 4g
broccoli (1 cup raw) – 3g
(bean) sprouts (1 oz) – 0.8g
figs (1 oz dried) – 0.9g
avocado (1 oz) – 3g
maca (1 tbsp powder) – 1g
kale (1 cup raw) – 2g
romaine lettuce (1 cup shredded) – 0.6g
For the most part, I wasn’t overwhelmed by the amount of protein in these foods. Considering that a single serving of protein is considered to be approximately 6-7g. Even if you consumed all of these foods in a day you would be consuming only 44.1g of protein in total. This is quite close to the needs for many women. Protein needs are generally 0.8g per kg of body weight. However, more protein may be needed in some cases such as for athletes, pregnancy, wound healing, childhood, elderly, etc. Even so, most of us handily exceed the daily requirements for protein.
There is something else beyond total protein to consider, however. We also need to look at protein quality. High quality proteins are those that contain ample amounts of all nine essential amino acids. I’m sure you already know this but just as a refresher… Amino acids are the building blocks of proteins. There are 20 (or 21 if you count cystine) amino acids, 9 of which are considered essential because our bodies cannot synthesize them and must, therefore, obtain them from food. Animal proteins (with the exception of gelatin) are considered to be high-quality as they contain all of the essential amino acids in ample quantities. Many plant proteins are considered to be low-quality as they are either low in, or lack, one or more of the essential amino acids. While it’s absolutely possible to obtain all of the amino acids we need from plant proteins it also takes more careful consideration than proteins obtained from animal sources. This is why we talk about complementary proteins. These are plant protein sources that, when combined, yield adequate amounts of all 9 amino acids. A few examples are: hummus and pita, rice and beans, veggies and polenta. Just to be clear, the complementary proteins needn’t be consumed together at the same meal (although they certainly can be) as long as they’re consumed throughout the day.
Generally speaking, aside from foods such as beans, nuts, and seeds, plant proteins are lower in total protein (not just essential amino acids) than animal proteins. Just a few examples: 3 oz of canned tuna has 21.6g of protein, 3 oz of chicken breast has 21.3 g, Greek yoghurt can contain up to 15-18g per serving.
Yes, it is possible to consume adequate protein without consuming animal products. It’s likely preferable if we do favour plant sources of protein over animal sources. However, it’s not as simple as those infographics make it seem. Most foods contain some quantity of protein. That second infographic especially irks me. Suggesting that romaine lettuce and figs are good sources of protein is ludicrous.