Lots of stuff packed into this post. First, I’ve updated my food guide to create separate groups for legumes and nuts as a way to ensure adequate protein intake.
I’ve been thinking about protein a lot lately for a number of reasons. The main one is that I’ve been working on a book on vegan nutrition with dietitian Jack Norris. It’s called Vegan for Life, and will be published this summer by Da Capo Press.
We worked on our book for more than a year and spent a lot of time researching and debating every single aspect of vegan nutrition.  Based on protein and amino acid content, we decided that nuts and legumes aren’t quite similar enough to be in the same food group.
Legumes (which include soyfoods) are an important part of vegan diets. In particular, those who avoid these foods may not meet requirements for the essential amino acid lysine. But, nuts have some important nutritional and health benefits, too, and—as long as you aren’t allergic to them—it’s a good idea to include a daily serving or two of nuts in meals. So giving each of these types of foods their own group ensures that you’ll get enough of both.  
I’ve also been giving lots of thought to protein because—no doubt about it—I’ve had ex-vegans on the brain over the past few months. I’ve wanted to focus on what can go wrong with veganism, and how we can do everything possible to make sure that all vegans and aspiring vegans have access to the safest nutrition information possible. And when people experience deficiencies on a vegan diet, we need to be able to help them increase nutrient intake from plant sources.  
For example, I happened across a comment on a veggie board a month or so ago posted by a vegan who was thinking about adding eggs back to his diet. He felt he needed a protein and fat boost. Well, okay—it may very well be true that his diet was falling short on these nutrients. But he could get both pretty easily from plant foods. A large egg has around 6 grams of protein and 5 grams of fat. You could get equivalent amounts of both by eating ¼ cup of tempeh, or ½ cup of beans topped with a couple tablespoons of avocado, or a cup of quinoa tossed with a tablespoon of chopped nuts.
People often don’t think of plant foods as a way to boost protein and fat intake, though, because vegan diets have a reputation for being low in both. In fact, this is often touted as one benefit of plant-based eating, which could cause some people to avoid higher-protein plant foods.
To ensure that vegans meet needs for protein and lysine, I recommend a minimum of three servings per day of legumes. A serving is ½ cup of beans or soyfood or 1 cup of soymilk. This is a fairly generous amount—more than some people require—but it leaves room for some low-protein foods in your diet—fruits, fats, and treats.
Here is a quick guide to meeting vegan protein needs. I’m including information about lysine, too, just to demonstrate why legumes are so valuable in the diets of vegans. Don’t obsess about your lysine (or protein) intake, though. As long as you are including legumes/soyfoods in your daily menus, you’ll meet requirements for both.
To find your protein requirements, multiply your ideal weight (in pounds) by 0.45.
To find your lysine requirements, multiply your ideal weight (in pounds) by 21.5.
 Protein needs are based on lean body mass, which is why we use ideal weight rather than actual weight to calculate requirements. So a person who should weigh around 140 would need 63 grams of protein and 3010 milligrams of lysine. You can check the chart below to see how you are doing in terms of meeting protein and lysine requirements. You may also want to check out Jack’s updated protein page to learn more about how protein needs are determined and where vegans stand in this regard.

 

Food
Total protein in grams
Total lysine in milligrams
½ cup cooked legumes
7-8 grams
485-625
½ cup soybeans
14
575
½ cup firm tofu
10-20
582
½ cup soft tofu
8-10
1 ounce veggie meats
6-18
Varies considerably but veggie meats that contain soy protein are likely to be good sources of lysine.
1 cup soymilk
5-10
439
¼ cup peanuts
8
310
¼ cup other nuts
2-6
80-280*
½ cup grains
2-3
55-85**
½ cup vegetables
0.5-2.5
60-165
*Pistachios are an exception; ¼ cup provides around 6.5 grams of protein and 365 milligrams of lysine
**Quinoa is much higher in protein and lysine than other grains, providing around 4 grams of protein and 220 milligrams of lysine