Protein Guide for Vegans and Vegetarians

If you are vegetarian or vegan, are you getting enough protein?

Why is protein so important and how much do you need? 

>>>>>Please see my other article How much protein do I need? 

When it comes to vegetarian options getting the amount of protein required is not a challenge, of course, it will depend on the type of vegetarian you are where including more animal options increases de feasibility of getting sufficient protein in each meal. 

For vegans on other hand, the story is different, most of the RDA recommendations(1) have 10% of animal products, so the minimum requirement of 0.8gr of protein per kg of body weight might not be adequate if you are having it completely from plant sources, in that case, consider a minimum of 1gr. 

This is because plant sources tend to be lower in quality than animal-based proteins, in other words, if you obtain 100% from plant sources you will need to pay closer attention not what the amount you need but to the quality of that protein. 

How is protein quality determined? 

Protein quality is determined by its digestibility and amino acid profile. 

Animal-based proteins have a digestibility higher than 90% whilst plant sources have a rate of 60-80%. 

Digestibility is important because you don’t absorb some of the protein you eat. Animal-based proteins have better digestibility (>90%) whereas the best plant sources (legumes and grains) have a rate of 60-80%. 

The best plant-based sources of protein that have over 75% of digestibility are wheat flour, wheat, peas, mung beans, corn and barley. 

It is important to mention that plants contain antinutrients that inhibit protein digestion and absorption while cooking reduces anti-nutrient concentration. 

A protein to be considered “complete” has to contain all the 20 amino acids, the 11 your body produces and the 9 essential amino=acids (EAA) that must come from food since your body can’t produce them. 

The higher scores of EAA from plants are Spirulina, mycoprotein, lentil, quinoa, and black bean containing around 60% while whey protein is 50%. 

Another thing to consider is that plant based-proteins are lower in the amino acids Leucine which is believed to act as a signal to “turn on” anabolic signaling pathways and Muscle Protein Synthesis (MPS). 

One way to solve the problem of EAA deficits in plants is to combine complementary EAA profiles.

Digestibility of various plant and animal-based proteins

Reference: FAO. Protein Quality Evaluation in Human Nutrition. 2013

Plant-based eaters might struggle to get sufficient protein in each meal

Well, this a debate that a plant eater may contradict, but if we look at the following graphs based on thousands of people we can see that non-plant-based eaters did better. 

How many meals each day contain a serving of high-protein foods? 

Reference: https://www.precisionnutrition.com/plant-based-protein

Considering putting some muscle or losing fat without compromising lean mass? 

To stimulate muscle protein synthesis (MPS) you need to consume at least 20gr of protein from animal sources or 30-35 from plant sources to get enough L-leucine. 

The graphic below shows the feasibility of ingesting different protein sources to get 20gr of protein. Notice that you need less than 1 portion from animal sources and 2-6 from plants to get that.

For ovo-lacto vegetarians 1-2 portions to get this.

As you can see, 20gr of protein from animal sources is very easy to get plus you don’t add many calories if your goal is to lose weight and retain lean body mass (LBM). 

The main issue with plant-based eaters is that the more protein you add the more difficult as you are adding extra calories and fibre resulting in more satiety. That is why many plant-based eaters opt to use protein powder blends to avoid this issue.

Reference:https://www.researchgate.net/publication/354561991_The_Anabolic_Response_to_Plant-Based_Protein_Ingestion

Plant-based sources to consider

For plant-based eaters consider getting your protein from sources that offer a good balance of amino acids and the combination. 

For good combinations think of a good blend of cereal-legume combo.

Some of the combinations include beans/soy and rice/soybean. These grain-legume combos work because legumes supply the lysine missing in grains whereas grains supply the methionine and cysteine missing in legumes. 

Unfortunately, most plants are low in leucine except corn, so eating a combination without corn won’t make much difference. meaning that you will need to consume more of those combinations of plants to obtain the same benefits. 

If your protein has less leucine you can supplement it with leucine as the feasibility of ingesting a large number of plants to get the right amount of protein and leucine might be quite challenging.

Select high-protein foods

Considering supplementing?

When considering supplementing there are some things to need to be taken into account:

As you can see soy is the best stand-alone complete protein, but if you get a blend of rice and pea protein, they combine to provide all the essential amino acids. 

That doesn’t necessarily make rice, pea, or hemp protein powders that aren’t blended poor choices. They just may not be as effective.

Takeaway

• Eat enough real food: when on a plant-based diet consider replacing highly processed protein sources with unprocessed ones. 
• Eat a variety of food: a variety of food means a variety of amino acids
• Supplement with a plant-based protein powder, if appropriate: some people want convenience and this is also I encourage my busy clients or the ones that struggle with planning, having a ready-to-eat protein powder or even to enrich some meals is a really good option. 
• If you are vegetarian/flexitarian: include strategic quantities of animal products, sometimes you can benefit from adding some animal products if your requirements aren’t met. 
• Be flexible: it’s okay if one day you miss your protein targets. 
• Select high-protein foods:

References:

1. https://www.ncbi.nlm.nih.gov/books/NBK234926/