“Don’t worry about protein; just eat enough calories and you’ll be fine!”
“All plant foods contain protein. Even spinach and broccoli!”
“I get my protein from beans, nut butters, and quinoa.”
Sound familiar? Phrases like these are very common in the vegan world, but each of them is missing some important context. Yes, all plants contain protein. And yes, you can get all the protein you need eating only plants. However, many conversations about vegan protein fail to take into account two key metrics:
1. Protein density (i.e., the percentage of a food’s calories that come from protein).
2. Calorie density (i.e., the energy content of a food, relative to its weight or volume).
In the chart below, you’ll see 20 vegan foods listed. The top section lists the cups of each food you’d need to consume to get 20 grams of protein, and the bottom section lists the calories you’d need to consume to get 20 grams of protein.
Plant-based protein sources
Data visualization by Vizable Insights
The foods on the left side of the graph are quite high in calories. For example, you’d need to eat over 600 calories each of almonds, peanut butter, or chia seeds to get 20 grams of protein. This translates to about 13% of the calories in these foods coming from protein. Thus, these foods have high calorie density and low protein density.
On the right side of the graph are foods that have much higher percentages of their calories coming from protein, that is, they have a higher protein density. To get 20 grams of protein from fava bean tofu, for example, you only need to eat 90 calories’ worth (90% of the calories in this food come from protein).
Why do we need to take both protein density and calorie density into account?
Take a look at this portion of the chart:
Remember that foods listed on the right side are very protein dense – a large proportion of their calories come from protein. And foods listed on the left side are very calorie-dense – you’d need to eat a lot of calories of these foods to get 20 grams of protein. Fifth from the right, you’ll see spinach listed. This means spinach has a relatively high proportion of its calories coming from protein: you’d need to eat only 166 calories of spinach to get 20 grams of protein, which is on par with firm tofu and nutritional yeast.
However, check out spinach in this portion of the chart:
Spinach has a very low calorie density. As you can see here, you’d need to eat 24 cups of spinach to get 166 calories’ worth! So even though spinach is technically high in protein as a proportion of its calories, it’s not useful in real-life contexts as a protein source.
A misleading social media graphic
Take a look at this graphic that’s making the rounds on social media. I’ve labelled it as misleading, just to make it super obvious!
The way the chart is laid out makes it seem like all the listed items are good protein sources, with the ones at the bottom delivering more protein than the ones at the top. In fact, they’re ranked based on 100 grams of each food. This doesn’t mean much if we’re not taking into account a food’s calories, and the percentage of which come from protein.
I’ve seen a lot of people commenting on the graphic, including:
“I never knew pumpkin seeds had so much protein.”
“Glad I’m eating my peanut butter.”
“That's awesome. Thank you for listing this. I’m pleased to know I’ve been eating a lot of the items that are super high in protein. Shared.”
Most of these items are not super high in protein. (They’re all amazing plant-based foods we should be consuming, but not for their protein content.) It’s great that this graphic has people talking about plant-based protein sources, but it’s missing two crucial pieces of information. You guessed it: protein density and calorie density.
Let’s look at potatoes, the first item listed in the chart. To get the absolute minimum amount of protein for a day, I’d have to eat 4.4 pounds of potatoes. That’s for a sedentary person. An active person of my body size would need to eat 10 pounds of potatoes to get enough protein for the day. Not exactly a useful protein source, is it? This is because potatoes have a very low protein density – only 10% of calories in potatoes come from protein.
Peanut butter is also listed on the graphic, duping people into thinking it’s a good protein source. One hundred grams of peanut butter contains 588 calories, only 100 of which come from protein. This means it's only 17% protein by calories, which is quite low. In contrast, fava bean tofu is 90% protein by calories. Regular tofu is 45%, and seitan is 75%. Those are all much more concentrated sources of protein. We all know tofu is an excellent protein source, but in this chart, it’s listed 7th from the bottom. (Again, grams don’t mean much if we don’t look at calories. One hundred grams of tofu gives you way more protein bang for your buck than 100 grams of peanut butter.)
Of course you can get all the protein you need from plants. But most of the items on this list won’t help you nail your protein goal.
After I shared on social media why this graphic is so misleading, many folks requested an updated one. This is how our new, more accurate plant-based protein graphic came to be!
So, what does this mean for your own protein intake?
First, use this vegan protein calculator to find out how much protein you need each day. Then, focus on the preferred high-protein foods in our chart. Use them as main protein items in meals, or add them to existing dishes you already make. This is by no means an exhaustive list, but it illustrates the relationships between calorie density and protein density. If you take both into account, you’ll have no problems nailing your protein goals.
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