How can I determine how much protein I need in a vegan diet?

Question

As I'm going vegan, I need to replace protein from meat with plant proteins. When I was eating meat, I didn't pay any attention to how much protein I ate. But in a vegan diet, I feel that I would have to look at it a bit more closely.

I'm now wondering, how I can determine how much protein I need in a vegan diet?

Answer 1

If you are having issues reaching your protein goals, you can supplement your diet with soy protein powder. It's cheap, a source of all 9 essential aminoacids, and it has a bland taste, so you can mix it into smoothies, shakes, salads, or even your lunch.

About "which quantity", we can't get the right number for you without knowing your weight, height, age, goals, and pre-existing conditions. If you are a healthy adult, you can estimate your TDEE needs here. Otherwise, you'll need assistance from a dietitian.

For the sake of calculations, let's use as example a person with a TDEE of 2,800kcal. Recommended protein intake would be in the range of 10-35%, so between 70-245g.

Translating that into some foods:

+-------------------+---------+------------------+-------------------+
|       Food        | protein |  Needed for 70g  |  Needed for 245g  |
+-------------------+---------+------------------+-------------------+
| Green peas (raw)  | 5%      | 1,400g (3.1 lbs) | 4,900g (10.8 lbs) |
| Black beans (raw) | 21%     | 350g (0.7 lbs)   | 1,200g (2.6 lbs)  |
| Seitan            | 75%     | 95g (3.35 oz)    | 330g (11.8 oz)    |
| Soy milk          | 3%      | 2,150g (4.7 lbs) | 7,450g (16.3 lbs) |
| Tofu (raw)        | 8%      | 875g (1.9 lbs)   | 3,100g (6.7 lbs)  |
| Peanut butter     | 25%     | 280g (9.9 oz)    | 980g (2.2 lbs)    |
+-------------------+---------+------------------+-------------------+

_{All food info comes from the US Department of Agriculture.}

Edit to shed some light on the calculations: I considered 4 kcal/g for proteins. 10-35% was calculated on top of total calories, i.e., out of 2,800 kcal/day, 280-980 kcal/day should come from proteins. The percentages were calculated by dividing total protein weight by total weight (water weight included).

Answer 2

A baseline protein requirement can be calculated based on bodyweight. Different multipliers are suitable for different lifestyles. Here are some recommendations for protein intake as measured in grams of protein per kilogram of body weight based on different stages of life and levels of activity.

• The estimated average requirement (EAR) is an estimate of adequacy for a median person. The Food And Nutrition Board sets the EAR for protein at 0.66 g/kg. This intake would be insufficient for 50% of the population.
• The recommended dietary allowance (RDA) is an estimate of adequacy for 97% of the population. The RDA for protein is set at 0.80 g/kg. Most people would have sufficient intake at this level.
• "Experts in the field of protein and aging recommend a protein intake between 1.2 and 2.0 g/kg/day or higher for elderly adults." (source)
• The International Society for Sport and Nutrition recommends "Protein intakes of 1.4 – 2.0 g/kg/day for physically active individuals"
• "Numerous research studies have found no benefits for a total protein intake exceeding 1.8 g/kg in resistance trained subjects" (source)
• Consuming 4.4 g/kg produces no observable benefit compared to 1.8 g/kg. (source)

This can be distilled into a simpler conclusion:

• A daily protein intake of at least 0.80 g/kg is sufficient to maintain long-term health and avoid chronic deficiency in most of the population.
• Some individuals are likely to benefit from increasing protein intake up to 1.8 g/kg.

An average Canadian male weighing 83 kg should consume between 67-150 grams of protein per day. An average Canadian female weighing 70 kg should consume between 56 and 126 grams of protein per day.

Some sources suggest that vegetarians and vegans should aim to consume a slightly higher amount of protein because of concerns about bioavailability or total amino acid profile, but I had a hard time locating scholarly sources to support this.