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Vegan protein
I saw a comment on HackerNews (HN) today that claimed “[g]reen leafy vegetables also [have] a lot protein (Kale, Broccoli and Brussels).” In the context of the thread, I didn’t feel like it was really appropriate to point out that this is not really the case, but for my own curiosity I did look up some numbers and felt they were worth recording somewhere:
| Food | Protein |
|---|---|
| Kale (raw) | 4.3 |
| Broccoli | 2.8 |
| Brussels | 3 |
| Eggs | 12.6 |
| Chicken | 24.7 |
| Lentils | 9.0 |
All of the protein values are from Wikipedia and in units of grams of protein per 100 grams of the food. Each food but the Brussels sprouts had a nice nutrition info panel with precise protein values, but the sprouts only said “3% protein.”
As you can see from the table, leafy greens are emphatically not a good source of protein. As a “bodybuilder”1, I’m probably a bit biased in that I (usually unsuccessfully to be honest) try to eat ~1 g of protein per pound of bodyweight, ideally in four ~50 g of protein meals per day. To achieve that goal for a single meal would require me to eat more than a kilogram of raw kale. The protein value for cooked kale is even lower at 1.9 g per 100 g. In contrast, I could eat 200 g of chicken or ~8 eggs (using 50 g as the size of a large egg according to Google). The HN poster also mentioned lentils and other legumes first, which are a more reasonable source of protein if you want to avoid animal proteins. However, another food I consider to have negligible protein, one slice of Wonder bread (28.5 g) contains 2.5 g of protein for a whopping 8.8 g of protein per 100 g. So you could eat 3.5 slices of white bread and get as much protein as 100 g of lentils.
Obviously there are other dietary considerations than just the amount of protein per gram of food, but it was a good excuse to find a few hard numbers to check the claim on HN.