Welcome to episode 435 of The Whole View! This week, Stacy and Sarah explore the science behind protein to determine whether getting protein for vegetables is enough to meet dietary requirements.
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The Whole View, Episode 435: Is Protein from Vegetables Enough?
Stacy tells listeners to hold onto their seats because today they’re talking about veggies! (2:37)
She takes a minute to say how excited she is for this listener question because of how complicated dietary stuff can get.
“I have been listening to you two ladies since way back when you first started in 2012. Geez I was 15?! But I feel very lucky to have had such wonderful role models as I grew up in a not-so healthy (food and body image-wise) environment. And am thankful that I could count on you two to encourage a healthier perspective both inside and out!
I was wondering if you could discuss the myth of protein combining. I feel like maybe the reason people new to the “whole” lifestyle (new word for ‘paleo’ a la your podcast name change) become meatheads is because of this myth that if we don’t eat meat we will not get all the amino acids we need.
However, as a biochemist and researcher, I have done the math using USDA nutritional guidelines. (2000 calories at 10-15% protein is only 50-75 g of protein with varying requirements for each individual amino acid) and their food database and found that as long as one eats ENOUGH PROTEIN PERIOD. It is literally impossible to not meet individual amino acid requirements – even consuming no meat, fish or eggs, as vegetables also have a significant protein-to-calorie ratio!
I understand that the digestibility of plant proteins is much lower than that of animal. But I thought you ladies would love another excuse to tout the benefits of increasing veggie intake. Plus, it make anti-inflammatory diets look more affordable when one understands that we don’t have to hulk out on proteins. Love you two and hope you are safe and well in the epic times of COVID we are experiencing <3″
Stacy expresses how much she loves knowing she’s been a part of someone’s life like that.
She also jokes that her brain is exploding a little that one of their listeners was inspired enough by these topics to pursue biochemistry!
Sarah thinks that this is a perfect time to dive into a question like this one since a lot of people are in the mindset of New Years Resolutions.
This means a lot of people might be considering adopting diets.
A lot of the diets popular in recent decades revolve around things you don’t eat, like Vegan or Keto, and tend to be on the extreme side.
Sarah suggests starting out by looking at what the requirements are before deciding whether getting all your protein from vegetables is enough.
Sarah wants to lay the groundwork for some listeners by expanding on some of the science talked about in the listener question. (7:19)
The recommended daily allowance of protein is 0.36 grams per pound body weight (0.8 grams per kilogram of body weight).
That amounts to 56 grams for a 150-pound person.
However, it’s important to emphasize that this number is considered a minimum daily allotment, and there is no established upper limit.
Sarah also explains that it’s really important to note that the science that goes into establishing these daily allowances is looking at signs of deficiency.
So we really need to look at the RDA as a bare minimum.
Many studies have evaluated diets containing three to four times more protein than this minimum.
It also has proven benefits to weight management, body composition, hormone regulation, and cardiovascular health.
Sarah loves this detailed article summarizing the science on protein intake.
- Your optimal daily protein intake depends on your weight, goal, and level of physical activity: from 1.2–1.8 g/kg if you’re sedentary all the way up to 3.3 g/kg if you’re trying to minimize fat gain during a bulk.
- That’s roughly ½ to 1 gram per pound BW – so more like 75 to 150 grams for that same 150 pound person
- You can quickly and easily calculate your optimal daily intake with our protein intake calculator.
Sarah explains that the optimal amount of protein is significantly higher than the RDA minimum target.
Also, the essential amino acids have RDAs as well.
The following is the World Health Organization recommended daily allowance for the indispensable amino acids for adults.
Again, these should be considered minimum targets.
Sarah also explains that it’s always better to give your body as many building blocks as possible from the food we eat.
This contrasts with making your body make the materials from other materials and then use them as blocks for what it needs.
Sarah also reminds listers that a “nonessential” nutrient isn’t something we can live without. But rather is something our body can make if needed.
Whereas essential nutrients cannot be made and need to come from outside sources.
Can We Get All 20 Amino Acid In Protein From Vegetables?
Yes, it is possible with a very careful combination of plant foods. (13:52)
Sarah explains that plants don’t contain all 20 amino acids naturally on their own. Some are higher in some than they are in others.
Animal protein sources, such as meat, fish, poultry, eggs, and dairy, are similar to the protein found in your body.
Complete protein sources contain all 9 of the essential amino acids that your body needs to function effectively.
Animal proteins generally contain good amounts of all 20 amino acids.
On the contrary, plant protein sources, such as beans, lentils, and nuts, are incomplete.
Sarah explains they tend to carry 10-12 out of all 20. And they are almost always deficient in at least 1.
This is because they lack one or more of the 9 essential amino acids that your body needs (1).
Complete vs. Incomplete
Some sources report soy protein as complete.
However, soy has only small amount of two essential amino acids, so it isn’t comparable to animal protein (2).
- Hence the classic combinations
- Beans and rice
- Lentils and almonds
If you consider all 20 amino acids, because our bodies can’t always produce as much of the 11 non-essential, it becomes really obvious how superior animal proteins are.
Sarah explains that the best thing we can do for our bodies is to give it all the blocks it needs straight from our food.
And when we look at it this way, we can see that plant protein is not complete in the way that animal protein is.
Stacy takes a minute to circle back and remind listeners that what Sarah is talking about here is amino acids and protein.
She explains that is doesn’t negate a lot of the other nutrients that we can only get from animals as well.
Stacy challenges anyone on a vegetarian diet to pull up the math.
She stresses how important it is to ensure you’re not accidentally missing anything crucial you won’t naturally getting from a vegetarian diet.
Digestibility: Protein From Vegetables vs. Animal Protein
Sarah tells listeners that this next part might sound familiar to anyone that caught their show on collagen. (20:50)
She explains that digestibility really comes down to how compatible that protein is with our digestive system.
It’s true that our bodies more easily digest animal
Digestible Indispensable Amino Acid Score (DIAAS) measures individual amino acids’ digestibility by analyzing fecal matter at the end of the small intestine.
This is in contrast to the previous protein ranking standard, the Protein Digestibility Corrected Amino Acid Score [PDCAAS].
The previous system measured absorption throughout the digestive system and doesn’t take into account protein absorption by gut bacteria.
The DIAAS score is calculated based on individual amino acid digestibility, the original amino acid content of the food, and human amino acid requirements.
The higher the score, the higher the protein quality!
While DIAAS scores have been calculated for only a limited number of foods so far, here are some protein quality measurements of common foods and protein supplements.
Any protein that isn’t digested by the small intestines is then pushed into the large intestine and can feed our gut bacteria.
Sarah says it’s also important to understand that the bacteria in our gut also needs protein to function optimally.
Protein From Vegetables For The Gut Microbiome
Protein is essential for the growth and survival of the bacteria in our digestive tracks. (24:20)
The body utilizes amino acids to synthesize bacterial cell components or catabolize (broken apart) through different pathways.
Amino acids are likely essential for optimal gut bacteria growth: arginine, aspartate, asparagine, glutamate, glutamine, glycine, lycine, serine, threonine, and the branched-chain amino acids (leucine, isoleucine, and valine).
Sarah says what interesting about these numbers is that it’s a little hard to decipher whether plant protein is good for the gut microbiome or not.
Stacy adds that her body doesn’t process whole milk for her. So she’s sure she’s not properly digesting and using the protein that comes from it.
She reminds listeners that while Sarah goes through all this information, it doesn’t take away from listening to your body and what works for you.
Benefits of Eating Animal Protein
Sarah explains it’s very important to understand that some proteins in animal products that we can’t get anywhere else. (28:11)
This is why most dietitians recommend getting protein from animal as well as protein from vegetables.
Animal protein is also associated with positive health effects, despite often being portrayed as unhealthy compared to plant protein (26).
The Nurses’ Health study reported that poultry, fish and low-fat dairy were associated with a lower risk of heart disease (27).
People who eat fish regularly are also likely to have a lower risk of heart attacks, strokes and death from heart disease (28).
One study of more than 40,000 males found that those who regularly ate one or more servings of fish per week had a 15% lower risk of heart disease (29).
Additionally, eating eggs has been linked to improved cholesterol levels and weight loss.
Sarah runs through several nutrients abundant in animal proteins that many people are deficient in.
Studies shows there are benefits to eating animal protein. And these studies are especially strong when it comes to eating fish and chicken.
Sarah reminds listeners that fish has a lot going on for it in terms of the gut microbiome, healthy fats, nutrients and minerals, etc.
But We Don’t Need to Eat All the Meat!
Sarah concludes that plant protein can count towards total protein, but it shouldn’t
Sarah concludes that plant protein can count towards total protein, but it shouldn’t be our only protein. (35:00)
Sarah says we can count proteins from soy, etc., toward that goal, but it shouldn’t be the only proteins we’re getting.
A nutrivore diet is “plant-forward” (rather than plant-based). This means that plant foods make up the bulk of the diet but still includes animal foods.
Sarah reiterates that we can benefit greatly from the modest consumption of animal foods- especially seafood.
3-4 ounces per meal is actually enough from a nutrient standpoint, rounding out total protein from plant sources.
To get all 150 grams of protein from animal sources, that’s still 6 to 8 ounces per meal.
Sarah explains that all these shades of diets avoid vegetables and fruits because of sugar, carbs, etc., which is actually to the detriment of the dieter.
This is because these diets demonize foods that actually have a lot of beneficial qualities and nutrients.
Stacy jokes that she finds none of Sarah’s information on protein from vegetables surprising. (39:40)
She also tells listeners that humans are biologically omnivores despite everything out there telling you this or that diet is best.
Stacy is big on veggies, as is Sarah. But she shares that she doesn’t feel her best without animal-sourced protein.
She also reminds listeners that if you’re deficient in something for too long (due to being Vegan, etc.), it can have detrimental health effects later on.
Sarah explains that moderation and balance are key.
Without a nutrient-dense approach, it’s really easy to be deficient in important nutrients.
And it’s that deficiency that causes us not to reach the health goals we went on a diet for in the first place.
When this happens, Sarah explains it’s important to target what we’re missing, rather than eliminate more or go on an even structure diet.
Food diversity is so important, and there really is a role for animal foods and plant foods on our plates.
Stacy shares that for her, it fluctuates.
She really tries to listen to her body and consume what it’s telling her to eat.
Stacy explains that it’s really important to reach a place of nutrient sufficiency, so you can be more attuned to what your body might be telling you.
We know that diet is very individual as to what will work for you. And there’s a reason why our bodies work in this harmony.
It’s less easy to have to learn so much and not have a set of rules. But it can be so freeing to tell yourself you’re focused on health and nutrient density and that you need both.
Stacy is hopeful that this is a place we can all go together in the next episodes!
Stacy also mentions she and Sarah will have updates about life over on Patreon and listen to the holiday episodes as they roll out.
Thank you so much for listening!