If you haven’t yet been asked this question you will be. And some of you may be wondering this for yourselves. Like so many things in life, on the surface this can be very simple, but you could also spend a lifetime studying the issue in depth. I’ll shoot for surface coverage here, with a few links to direct you towards further information if you’re interested.
All whole foods contain some protein, but obviously some foods have higher levels than others. In Dr. Fuhrman’s book he talks about how he tried to design a diet that didn’t contain enough protein using his guidelines (Lots of leafy greens and vegetables, and least 3 fruits a day, whole grains in moderation, no refined foods, no fruit juice or added sweeteners, etc.) and it couldn’t be done. So, if you only eat those very nutrient rich foods you’re set, not many of us do though. How much protein is enough? The Recommended Daily Allowance is 40 to 70 grams a day, based upon your age and sex, etc.
Really, in practical application, it is probably more important to understand about complete vs. incomplete proteins than it is to worry about how many grams of protein you are eating each day. What is meant by a complete protein? To qualify as complete, a protein source needs to contain all of the amino acids your body needs but cannot produce on its own.
On a plant based diet then, you need to think a bit about complete proteins and the food combinations needed to supply them. Because plant protein sources tend to individually be low in one or more of these essential amino acids, they need to be eaten in combination to supply your body with the correct nutrients. It’s really very simple, eat a bean and a grain. That’s it, their nutritional profiles compliment each other. If you think about it, a lot of traditional foods contain this combination. Rice (brown) with beans, burritos (whole grain tortilla), rice (brown again) with Dal, even Peanut Butter and Jelly and Whole Wheat bread. Make sure that you vary the particular beans and grains you are eating, because if you only eat the same grain and bean combination every day you could still come up short on needed nutrients. It would be like only eating tomatoes and broccoli, and sure they’re great, but you’re not going to get the nutritional benefits of a more diverse diet.
Here’s an example of a days’ worth of food, Herbivore Style and its protein content:
Breakfast: Smoothie made with 1 cup of almond milk, 1 banana, and 1/2 cup of blueberries
Lunch: Salad consisting of 2 cups of romaine lettuce, 1 cup of diced bell pepper, 3 Tablespoons of sunflower seeds, and 1 cup of diced tomatoes
Dinner: 1 cup of cooked kale and a grain and bean salad consisting of 1 cup of quinoa (cooked in vegetable broth), 1 cup of navy beans, 1/4 cup of green peas, and 1/2 cup grated carrot
These meals add up to a protein content of 44.52 grams. And I would guess this example is a bit light on quantity/calories for most of us (but I didn’t calculate that).
Finally, I want to mention that when you read through some of the older texts on vegetarian diets you’ll see the recommendation that these complete protein combinations be eaten together (at the same meal), more recent research indicates that this is not true. Eating foods from both categories sometime during the day or even a day apart from each other will work too. Our bodies store the needed amino acids while waiting for the missing pieces they need. Just don’t make them wait too long.
*Protein levels for the various foods cited taken from the website The World’s Healthiest Foods and the side of the Almond Milk carton.