Protein is having its moment for sure. We hear about the importance of protein for metabolism, blood sugar balance and health but many “high protein meals” you see on Instagram are plant based and may be missing the mark for a few important reasons.
Most women in my practice, when asked “are you getting enough protein” answer, “I think so, I mean I do try!” This article will help clear up plant protein confusion so your efforts to get enough protein can be more impactful.
Some of the struggle with protein can be with not understanding how much women actually need and often we overestimate how much we are getting each day because again: we are trying! I cover all of that in this article, but sometimes the issue is that we are trying to get adequate protein without using animal protein or using it interspersed with vegetarian protein sources. While that minimum 100g protein day goal can be met on a plant based diet it is much harder and there’s a few things to keep an eye out for because there’s nothing worse than working hard to get enough protein only to be frustrated with your results.
Complete Proteins
You’ve likely heard that you can combine a grain and a legume to get a complete protein from plant sources (FYI animal proteins are already complete and need no additional combination with other foods) or you’ve read that certain grains such as chia are in fact “complete”.
The term complete when it comes to protein means that this food or combination of foods give you all nine essential amino acids (essential amino acids are ones we need to eat or consume, those we can’t synthesize on our own). So yes, you can combine various plant based protein sources to ensure you get all of the essential amino acids consumed however, when it comes to getting all of these amino acids from a plant based source there are three bigger problems to consider: amino acid bioavailability, hormone response and low leucine concentration in plant based proteins (a key aspect to triggering the building of lean mass, AKA muscle, read more about MPS or muscle protein synthesis in this article).
The conversation about using plant based proteins has largely been about this idea of getting a complete protein and it’s really just one part of the protein picture and as you read on you’ll see it’s hardly the biggest consideration and to be honest, it’s one of the easier things to accomplish when it comes to using plant based proteins.
Bioavailability
Plants are so good at so many things including being those “super foods” we talk about in terms of phytochemicals such as antioxidants and they are our best sources of fiber which helps digestion, balances blood sugar and has years of research on favorably impacting health.
And while plants are lower in protein in general, the protein they do contain (AKA plant based protein) is simply less easy to absorb and assimilate than animal protein. This can create digestive symptoms for some but more to the point, it means you need to consume more of it to hit your amino acid needs.
This will bring with it more calories and more carbohydrates, so you need to consider this especially if you have a weight loss goal in mind or are being mindful of carbs (i.e. you have diabetes, insulin resistance, PCOS or are in perimenopause or menopause) or calories in general. More on that below.
If you tolerate those additional starches, can you get adequate protein using plant sources? Yes you can, but you have to work a lot harder to get enough protein as well as round out the amino acid profile. For example, if your pea protein shake says it has 12g protein per serving consider you’re likely getting 6g and not 12 and calculate your needs accordingly.
This also means that most women relying on plant based protein sources often have to utilize protein powders and this can get a bit tricky. A rice+pea blend is going to offer a more complete array of amino acids, so this is one consideration. Other plant based options include plain pea, hemp, chia, etc. but it’s worth noting the pea protein is generally high in arsenic. This amount of arsenic is not likely a problem with occasional use of a pea based protein powder however, do be aware of this if you are using pea protein powder daily or even more than once a day.
Hormonal Response
When we drill down on protein content of a food, i.e. 18g protein in a serving of lentils also comes with 36 g of carbs (14 of which is fiber making it net 22g carbs). So it is slightly more carb than it is protein despite being considered a high protein food by many.
Does this mean lentils are bad? Nope, not at all.
But if you are watching your carb intake because you feel better, get better results or they aggravate your blood sugar then you have to consider this. Lentils or other legumes might be a perfect carb for you say compared to bread or even whole grains, but just don’t make the mistake of counting these mixed bag, plant based “protein sources” as solely protein when you are also getting some starch in there too because that will have a different blood sugar and thus insulin response for most of you.
For what it’s worth, a chicken breast has 23g protein and zero carbs – which is the case for animal protein in general.
How about digestibility of legumes? Soaking lentils and beans can certainly alleviate some gas/bloating that happens with these foods. There is also the question of lectins in legumes as far as inflammation and negatively impacting gut health. This will be a consideration for some but not all women. If you have gut issues such as IBS or hormonal issues like endometriosis or any type of autoimmunity then it is something to consider as a potential problem and worth looking into how you personally respond in terms of digestive symptom, signs of inflammation, lab markers, etc..
What About Nuts As A Plant Based Protein Source?
Nuts are less of a hormonal response issue but a serving of nuts such as 1oz almonds, which is approximately 23 almonds, contains 6g plant based protein (so consider it 3g when we account for absorption issues) and 14g of fat. So to get the equivalent of 23g of protein in the chicken breast you’d have to eat four servings of nuts giving you 144g of fat.
Almonds also have 3.5g of fiber and are most definitely a food with a variety of benefits in terms of healthy fats and nutritional value, but it’s very difficult to get adequate protein from nuts – while it’s certainly easy to get a lot of calories and a hefty dose of albeit “healthy” fat.
Building Lean Muscle (AKA Muscle Protein Synthesis) Needs Leucine
While complete proteins get all the attention when it comes to plant vs. animal protein discussions, amounts or ratios of specific amino acids and not total number is a very important part of the conversation.
I dive deeper into how we make lean tissue, or build muscle, known as MPS or muscle protein synthesis in this article but in simplest terms we need not only enough protein to do this but a certain amino acid called leucine is needed trigger this process.
When we eat food that contains protein, that protein is broken down or digested into smaller parts of proteins called peptides and into individual amino acids. When it comes to building muscle we need enough of the specific amino acid leucine to trigger this process, 2-3g to be exact. And we need this trigger several times a day, ideally every time you eat and maybe even within that 2 hour post workout window as well.
Animal protein has this optimal amount of leucine built right in, whereas plants are quite low in leucine. You can supplement a plant based diet with a higher leucine amino acid blend like KION to get this muscle building trigger.
Can you make it all happen on a plant based diet?
It’s possible to be a protein mindful vegetarian but it’s a lot of work and requires supplementation with iron, b vitamins and added leucine among other amino acids. It is also clearly easier to get adequate protein as well as key nutrients like iron and B vitamins in a whole foods, unprocessed form by eating animal protein.
However, if you are committed to a vegetarian lifestyle be sure to use something like KION to supplement and if you’re open to eating dairy and eggs, include as often as you can. It can be done, you just gotta be really smart about it.
Also, I LOVE PLANTS! Plant based foods are our best sources of both fiber and phytonutrients including antioxidants such as flavonoids and glucosinolates like those in brassica veggies that help with hormone metabolism and have some research to show they are anti-cancer as well. So eat those plants! It’s just ideal to pair them with an high quality, ethically raised animal protein source.
Note on Iron & B12
Oxygen is one of those metabolic deal breakers, you simply will not function well if you can’t carry oxygen well – and you need iron and B12 for that, both of which are found in animal products. With regards to B12, it’s simply not high in plant based foods and it’s a common deficiency in vegetarian diets. As for iron, it’s important to note that there are two types of iron: heme and non-heme. Non-heme iron is what is found in plant based foods and it’s not absorbed well making heme iron from animal protein or supplements the clear winner for our health. Iron can be supplemented as a chelated form or in products that are liver based as well as the cheaper version: ferrous sulfate which is more poorly absorbed and causes more issues with constipation.
Low B12 and/or iron will result in low energy, difficulty thinking and concentration and can lead to anemia. As we age, we can develop lower levels of these nutrients even when we’re eating them due to digestive issues, but they can be easily monitored on standard blood tests.
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But Dr. Brooke it’s so confusing because real food is so mixed!
Yes, real food contains proteins, carbs and fats, how do you consider this all and keep your nutrition plan simple?
What I tell my patients and how I manage this myself is this: if you eat an omnivore diet (plants and animal protein): count animal protein as protein, consider veggies as fiber, count legumes and grains as carbs and think of nuts as fat. Any protein you get from legumes, grains or nuts is just bonus!
If you opt for plant based proteins you just have to factor that in with a bit more math, due diligence and a few supplements.
It can be tricky not to get emotional when we talk about animal protein, I get that and our modern farming practices are absolutely alarming.
When it comes to the biochemistry and hormonal response though, the science is what it is. So be sure to purchase from and support small, local farms vs. larger, factory farms and if you are committed to a vegetarian diet for ethical reasons be sure to supplement as needed to try and recreate the chemistry required to get you the protein you need for muscle mass, hormone response, energy and health. Again, you can do it just be smart about it!
As always, no judgment here and you get to choose what you eat. This article was intended to help you better understand the differences between various protein sources/types and how to get what you need on a daily basis. Most importantly, this article was intended to help you understand why you might, for all your efforts, not be getting the results you think you should be when it comes to “getting enough protein”.