Animal vs Plant Protein
Diet volumetrics
We compare the food volumes needed to meet protein requirements from plant and animal sources.
A common concern for people who are transitioning to a plant-based lifestyle relates to protein. The major challenge is consuming a broad spectrum of amino acids to meet your body’s protein requirements.
Few plant-based protein sources offer a complete amino acid profile (that means they don’t contain all nine essential amino acids in a single source – they’re called incomplete proteins) and you need to get these amino acids from your diet because your body cannot produce them.
The solution isn’t complicated. Simply combine multiple incomplete protein sources to deliver a complete amino acid profile (these are known as complementary proteins). This is an effective way to meet your daily protein requirements when you don’t include meat – a complete protein source – in your diet.
Adding bulk
But with that element covered, another issue often arises namely derived protein. Active individuals require 1.6g of protein per kilogram per day (g/kg/day). That means a 70kg person needs 112g/day from their food and supplements.
You can often achieve that target with smaller animal protein portions than with plant foods. For instance, a 100g steak contains significantly more protein than 100g of black beans. In fact, to get the same 22g serving of protein you would need to consume 250g of black beans.
That means, depending on your plant protein sources, you might need to eat more plant foods to meet your daily protein intake requirements. And you may require multiple plant-based protein sources to achieve that all-important complete amino acid profile.
You’ve been served
Consuming this higher volume of food can prove challenging for some people. Compare these animal-based and plant-based protein servings as references:
27g of protein = 100g venison OR 300g chickpeas
24g of protein = 100g lamb OR 100g cashews + 100g lentils + 100g spinach
22g of protein = 100g salmon OR 100g almonds (that’s 3.5x the recommended serving)
10g of protein = 100g Greek yoghurt OR 200g cooked quinoa
The digestibility dilemma
Then there’s the issue of digestibility. Animal-based proteins like whey, eggs, milk and beef are highly bioavailable. That means a large proportion of their protein content is digested and absorbed – 99%, 97%, 95% and 90%, respectively.
But even though you need to eat more plant food to meet your protein requirements, your body tends to absorb significantly less plant protein. For example, black beans have a digestibility of approximately 75% due to the presence of fibre and lectins, which can inhibit the absorption of some of the protein and other key nutrients.
This actually increases the total volume of plant-based foods we need to consume to derive sufficient protein to meet our daily requirements.
Nutrient density
Fortunately, most protein-rich plant sources aren’t calorie-dense and are, instead, nutrient-dense as they contain other beneficial components like fibre, along with loads of vitamins and minerals, with less saturated fat and cholesterol than meat. Protein-rich plant foods are also traditionally cheaper than animal ingredients.
Just be aware that some plant-based protein sources can break the ‘calorie bank’. For example, a 100g serving of natural peanut butter, which offers a serious 25g of protein, also contains a whopping 588 calories. Comparatively, a 100g sirloin steak provides 30g of protein with just 183 calories.
Protein variety
Faced with these hard facts, the case for protein variety in plant-based diets becomes abundantly clear.
Meeting your daily protein requirements on a plant-based diet requires more than just a complete amino acid profile. You also need sufficient amounts of this important macronutrient. This often requires blending large volumes of conventional plant-based protein sources with protein-rich options in your eating plan.
Researching the protein content of each plant-based source and its amino acid profile, along with its calorie content and appropriate serving size will ensure you meet your daily protein requirements.
And it’s important to pay attention to what else these ingredients contain, like healthful plant-based fats, to create a balanced and nutritious eating plan that doesn’t exceed your recommended daily calorie intake.
The supplement factor
Adding a plant protein powder to your diet is a simple like-for-like serving swap. A serving of plant protein delivers a complete amino acid, as would a serving of whey, with a relatively equal amount of protein.
