If it was good enough for Popeye – protein for vegans

We all know how important protein is. There are few vegans who haven’t been asked the old chestnut, “but where do you get your protein from?” It’s the standard objection. So, I thought I’d put together a fact-check covering everything that we, as vegans, need to know about protein.

What is protein?

The Oxford dictionary describes protein as “a class of nitrogenous organic compounds”; another definition is that it’s a macronutrient. Protein is made up of long chains of amino acids (molecules of carbon, hydrogen, oxygen and nitrogen). The human body needs twenty different amino acids to make protein molecules. Some of these amino acids are manufactured by the body and others are acquired from the food we eat. These are called essential amino acids.

The essential amino acids are: isoleucine, leucine, lysine, methionine, phenylaline, threonine, tryptophan, valine and histidine. Each of these is available in varying levels in all plant foods. The remaining eleven (alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, proline, serine and tyrosine) are made by the body using those listed earlier supplied in the diet. There’s more science and some great diagrams here.

Why do we need protein?

It’s a given that everybody needs protein, right? But what exactly does it do? Protein is essential for life; it is a component of muscles and bones, maintains cells and makes replacement ones and builds new cells in growing babies and children. In fact, the human body  is comprised of about 15% protein. Proteins are also involved in other functions, such as antibodies and the immune system, enzymes and hormones. In a nutshell, protein sustains life.

How much protein do we need?

Calculating your ideal protein intake is quite simple. It’s just based on weight (or ideal body weight if you’re tipping the scales a bit). The general consensus amongst dietitians is that vegan adults need 0.9 grams of protein per kg (kilo) of body weight. Certain groups need different amounts of protein; for example, growing children, pregnant women, athletes and the elderly. Two other “targets” to consider in relation to your vegan diet are that 1 gram of protein is 4 calories and you should aim to acquire 10 to 20% of calories intake from protein. What does this mean?

An average adult weighing 70kg with a 2000 per day calorie allowance would need:

0.9g x 70 = 63g protein | 15% of calories = 300 cals or 75g protein

So, whichever way you choose to calculate your protein intake a reasonable range is between 63g and 75g for this sample.

Where do vegans get their protein?

Ah, the perennial question! Answer, plant foods, of course! As mentioned above, all plants contain protein, including the full range of essential amino acids. If you’ve been vegan for a long time (well, since the late 1970s) you might have come across the concept of food combining. The remise of this, which was widely promoted at the time, was that different types of food needed to be eaten together in order to obtain the full range of amino acids required. I recall that this was even mentioned when I did my diploma at the Vegetarian Society Cookery School back in 1990s. However, the good news is that this is not a rule and has since been disproved by science.

What are the best sources of protein?

So, the evidence all agrees that plants contain protein. Phew! But, not all plants are equal and some contain higher amounts or are more protein-dense. Some of the best sources of protein are legumes (beans and peas, plus peanuts), nuts and seeds, seitan and soy products. Here’s my top ten: black beans (39g per cup); chickpeas (39g per cup); pistachios (25g per cup); seitan (25g per 100g); tofu (19g per 100g); lentils (18g per cup); kidney beans (15g per cup); oats (12g per cup); baked beans (14g per cup) and good old potatoes (2 medium-sized = 8.5g).