What is the daily recommended intake of protein?
Your protein requirements depends on your age, weight, height and health but as a guide, the recommended dietary intake (RDI) for protein (measured in grams per kilogram of bodyweight) is:
- 0.75 g/kg for adult women
- 0.84 g/kg for adult men
- Around 1 g/kg for pregnant and breastfeeding women, and for men and women over 70 years.
Plant protein 101
We spoke to Steph Lowe, The Natural Nutritionist and Author of Low Carb Healthy Fat Nutrition, to explain everything you need to know about plant-based protein.
How does plant protein differ to animal sourced protein?
Essentially, proteins are made up of amino acids and they’re the building blocks of life. There are what we call complete sources of proteins, which contain all of the amino acids that we can’t create ourselves (essential amino acids) and the incomplete sources, which contain some but not all of the essential amino acids. Animal proteins are the best sources of complete proteins, so when choosing a more plant-based diet, we need to be particularly conscious of consuming a variety of plant based protein sources to obtain the required amount of essential amino acids.
The top plant-based protein sources are:
- Tempeh and tofu
- Lentils and beans
- Nuts, including almonds, walnuts, cashews and their respective butters
- Seeds, including chia, hemp, flax, sunflower and sesame
- Green leafy vegetables, including broccoli and kale
To set the record straight, a vegan following a “starchitarian diet” (a carbohydrate loaded plate) could be at risk of falling short on protein or amino acid requirements, but it’s certainly not the case on a well-managed plant based diet. It does mean that more attention needs to be placed on dietary variation and high quality sources of protein, as excessive intake of soy or a diet of vegetables and carbohydrate simply won’t do.
Are there particular nutritional benefits of choosing plant protein over animal?
One of the largest benefits of choosing plant proteins is an increased consumption of plants in general. Regardless of your dietary preference, almost every one egress that increasing our consumption of fruits and vegetables is highly correlated with increased health and longevity. It is also one of the best decisions we can make for our microbiome health as an increased intake of dietary fibre is highly correlated with a well-balanced internal ecosystem.
While I always recommend supporting sustainable and ethical farming and ensuring our animal protein is free range, grass fed and pasture raised if we do choose to consume it, many are not yet aware of the significance of this purchasing decision. As a result, consuming more plant based protein means we are decreasing our support of factory farms and the environmental, sustainability and health implications of such farms. As a side note, switching to free range, grass fed and pasture raised animal protein can be extremely cost-effective if you shop at your local butcher or farmer’s market, or direct from the farm. Cost does not need to be a barrier to supporting both our health and the health of the environment.
Is there anything readers should be aware of when relying solely on plant-based protein?
The three key nutrients we must be conscious of are B12, iron and omega-3. Let’s take a closer look.
Adequate intake of B12 is essential for DNA synthesis and maintenance of myelin sheath (part of the nervous system). B12 can be stored in the liver for years, which is why many of those on a planed-based diet don’t notice signs of deficiency (fatigue, shortness of breath and palpitations) for two years. That’s not to say however, that some don’t show signs of depletion much, much sooner. Some vegan foods like soy, nutritional yeast and grains are B12 fortified, but not with nearly enough to achieve the levels required or replicate the bioavailability of B12 from natural sources including liver, eggs, chicken and fish. For anyone following a pure plant-based diet, B12 supplementation is a non-negotiable and the required dosage is considerably higher than traditional recommendations, simply due to the decreased bioavailability of synthetic sources.
Inadequate intake of iron can lead to varying degrees of deficiency ranging from low iron stores (indicated by low serum ferritin levels) right through to anaemia. Iron is essential for the transport of oxygen to muscles and cellular energy production, processes crucial to great health, energy and endurance performance, to name a few. The concern around iron is due to the reduced bioavailability of iron from plant based sources, however a well-planned plant based diet can contain adequate iron. This can be achieved by consuming foods such beans and lentils, tofu, tempeh, broccoli and green leafy vegetables. Iron absorption can be enhanced by consuming these foods alongside vitamin C such as via pairing tempeh with broccoli, capsicum and/or cauliflower. Anyone following a pure plant-based diet should undertake regular blood tests to monitor both B12 and ferritin levels and avoid deficiency.
3. Omega 3
Omega-3s are broken down into three forms, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and alpha-linolenic acid (ALA). ALAs are found in foods like flaxseeds, chia seeds, walnuts and green vegetables, and are required to create EPA and DHA in our body. There is evidence to show that DHA supplementation in particular, may be beneficial for vegan athletes to assist with training induced inflammation and oxidative stress. For optimal health you may require an algae based DHA supplement and to prioritise the consumption of the ALA rich foods mentioned above. As always, please ensure you moderate your intakes of omega-6 oils, and avoid vegetable oils including canola, corn and safflower oils.
Best sources of protein on a plant-based diet
1. Nuts and seeds
6g protein per serve of almonds
Nuts and seeds are a great sources of plant-based protein, fibre, vitamins, minerals and healthy fats, plus a whole host of other health benefits. A study published in BMJ Nutrition, Prevention & Health found that swapping out just half a serving of less healthful food (like red meat, processed meat, French fries, desserts, or potato, chips) for nuts is linked to less long-term weight gain and a lower risk of obesity in adults. Almonds, for example, offer around six grams of protein per serve and can be smashed as a snack on the go or spread in butter form on your toast.
8g protein per serve (1 cup)
Not only is quinoa packed with fibre, it’s also a great source of plant-based protein. One cup of cooked quinoa (185 grams) contains eight grams protein, plus a stack of other significant health benefits. According to research published in European Journal of Nutrition, quinoa was shown to reduce blood sugar, insulin and triglyceride levels. Meanwhile, animal-based studies showed the grain also has anti-inflammatory properties.
8g protein per serve (100g)
Stacked with all nine amino acids tofu offers a great plant-based supplement for meat, especially in stir-fries and salads. Derived from soy, tofu is a stacked vegan protein offering eight grams per 100g serving. Research from The Journal of Nutrition has also found that the soy proteins found in products such as tofu can assist in lowering cholesterol levels (LDL).
15g protein per serve (1 cup cooked)
Advocated by hummus addicts globally, chickpeas are a great source of vegetarian protein in a plant-based diet with one cup of cooked chickpeas containing 15 grams of protein per serve. Research published in Annals of Nutrition & Metabolism found that the legume can also lower the amounts of bad cholesterol in the blood.
9g protein per serve (1/2 cup)
While they might not come across as the most exciting of foods, lentils are a great source of protein with up to nine grams per serve. On top of that lentils are rich in iron, magnesium, potassium and zinc, all of which are essential in a plant-based diet. A study published in Advances in Nutrition also found that lentils are great for weight management, offering a valuable source of slow release energy.
Stack your plate with veggies high in protein. These include broccoli (2.6 grams per serve), asparagus (2.9 grams of protein) and Brussels sprouts (3 grams of protein per serve).