Plant-Based Q&A

Answered by Precision Nutrition Experts

A few days ago, there was a live webinar in our Precision Nutrition private group, where Ryan Andrews and Brian St. Pierre answered questions from coaches about plant-based diets.

I took notes and here are answers to some of the questions that were answered during the webinar.

Ryan Andrews

Ryan Andrews


Ryan Andrews is a principle nutritionist and adviser for Precision Nutrition and an adjunct instructor at Purchase College, State University of New York. He holds master’s degrees in both Nutrition and Exercise Physiology from Kent State University and a BS in Exercise Science from the University of Northern Colorado.

Andrews is also a Registered Dietitian (RD), Certified Strength and Conditioning Specialist (CSCS) through the National Strength & Conditioning Association (NSCA), a certified exercise physiologist (ACSM), and a Registered Yoga Teacher (RYT).

He frequently writes and speaks about nutrition, health, and sustainable food systems and has accumulated over 1000 hours volunteering at organic farms and with non-profit food recovery organizations.

Brian St. Pierre

Brian St. Pierre


Brian St. Pierre is the director of nutrition at Precision Nutrition, the coauthor of Precision Nutrition’s Level 1 Certification textbook, The Essentials of Nutrition and Coaching, and the mastermind behind the Precision Nutrition Calculator.

St. Pierre is a Registered Dietitian (RD), Certified Strength and Conditioning Specialist (CSCS) through the National Strength & Conditioning Association (NSCA), and a Certified Sports Nutritionist (CISSN). He also serves on the Men’s Health Network (MHN) Board of Advisors.

He holds a master’s degree in Food Science and Human Nutrition from the University of Maine.Prior to joining Precision Nutrition in 2012, St. Pierre was the head sports nutritionist and a strength and conditioning coach for Cressey Sports Performance, a high-performance facility in Hudson, Massachusetts and Jupiter, Florida.

Text written in italics is my commentary that I added for better comprehension, notes, and tips.

What are the differences in plant-based diets like vegetarian, vegan…?

Brian St. Pierre: 
PB doesn’t have a true definition. It is a spectrum. On one end there would be vegan, on the other end carnivore. Vegetarians don’t eat meat but some include include dairy or eggs or even fish.
People don’t neatly fit into boxes. Occasionally, people eat also foods that they exclude. For example some vegetarians who normally don’t eat fish, choose to eat it at a family celebration.

What are some of the reason people try PB diet?

Ryan Andrews: 
The reasons vary from being very personal to trying to solve their weight or health issues.
There are also reasons that extend beyond one’s personal health – animal warfare concerns, work conditions along the food chain, ecology and climate change, soil and air.
A shift towards more PB diet can help to solve some of those issues.


Why are people worrying about protein on PB diet

Brian St. Pierre:
If you are fully PB, it requires more effort to get enough quality protein in your diet, while animal sources are rich in quality protein. So when you exclude those foods you need to be more conscious about your food choices. Technically speaking, you need to also eat a little bit more protein to get the same amino-acids.

Minimum vs maximum protein needs? What does getting enough protein mean?

Ryan Andrews: 
Human body is pretty adaptable and we can get by with little protein but there is a difference between what is enough for just getting by and for performance or health.
Lower end 0.8g/kg. High end: 4g/kg.
Sweet spot range is somewhere in the middle, at about 1.2-1.6g/kg.

What are some good plant-based sources of protein?

All plant foods contain some protein. It is more about how much protein do you get per serving of that food. Some good protein sources include legumes, tofu, edamame beans, tempeh.
Some people argue that some nuts and seeds are also protein dense. With nuts and seeds you would be getting good amount of protein but also a lot of fat. Calorie dense nuts and seeds are problematic for people with low activity who choose to eat them as their protein source. They simply get too many calories in their diet as a result.
Foods that you eat often can make difference over a long time. Eating sweet potato as your main carbohydrate source does not provide much protein, but if you switch it for teff, you get 3x more protein from it.
Try switching wheat pasta for beans pasta, for example.

What is the perfect combination of food to get the optimal results?

Ryan Andrews: 
Think about complete meals instead of macro-nutrients. We don’t eat macronutrients, we eat food. All food contains some protein as mentioned above.
If you can have go-to meals that you know that can provide enough protein, you will not be indecisive about combination of food.
Find your go-to protein sources that you like and can consistently have in your diet makes it easy to get enough or more than enough protein. It is good practice to get protein from different sources like legumes, nuts, seeds and whole grains, but you don’t need to combine them in each meal.

Should PB eaters supplement with PB protein?

Brian St. Pierre:
Could they? Might They? Sure.  If they are struggling with protein intake, it can help them to reach their protein intake. But you should not structure your PB diet around protein powders.
It also depends on the protein powder. Nowadays, PB proteins tend to be equal to whey proteins.
Ryan Andrews: 
If you use protein, make sure it is quality controlled due to heavy metals.
Plant-based proteins have been shown to elicit lower blood amino acid concentration compared to whey, even when equated for amino-acid content. (Source). Should you worry about it? I don’t believe so. More important factors come into play when you want to optimize your protein intake such as getting enough overall protein and have it spread throughout the day in 3-5 meals.
Some good proteins on the market are: Sunwarrior, MaxSport, DM vanilla protein, Vivolife.

What about seitan?

Ryan Andrews: 
Seitan is a rich source of protein, but it does not offer as much nutrition as tofu or tempeh. If you tolerate and enjoy it is O.K. to have it. It is a protein source and it adds variety.
Brian St. Pierre:
It is more processed food option, mostly delivering protein (lacking lysine) without other supporting nutrients. It is like protein powder, you don’t build your diet around it.

Transtitioning to plant-based diet

How to remake meat-based meals into PB meals?

Ryan Andrews: 
An easy way to transition for a lvl 1 eater (anybody reading this) would be swapping meat for tofu or tempeh . Tofu and tempeh are most comparable to animal sources and most similar to the way you might prepare them. They also have pretty neutral taste so you can marinade them and use the same spices as you would for meat dishes.
When it comes to plant-based eating recipes and inspiration, you’re only limited by your imagination and Google skills.

Phytoestrogens and soy

Brian St. Pierre:
When we look at the research, we see soy and soy products are safe to consume. No one is suggesting you should eat soy for breakfast, lunch and dinner. The negative effects in studies were observed only with copious amounts of soy protein consumed. If you are using other protein sources like legumes and seitan, it would not be a concern unless you get symptoms.
Ryan Andrews: 
Most Americans eat a lot of ultra-processed and nutrient deficient foods so it would be beneficial for them to eat more soy. You don’t need to eat it every day.

Indicators that the PB diet works or doesn’t work for you.

Ryan Andrews: 
Depends on the client and why they want to make the transition. You can look at blood markers, body composition markers, how they feel about it, gastro-intestinal issues and decide based on that.
What Ryan is saying here, success of any diet depends on the outcomes you expect to get from it. If you want to improve your health and the diet you are following is not improving it, you need to take a different approach.
Brian St. Pierre:
“How is that working for you?” In the PB eating definitive guide there is diet satisfaction score. If you are doing this for a while, you can re-take it.
For example, your performance has gone up but you are having GI issues – it is a trade off and you need to decided whether performance or GI issues is more important for you.

Are nutrition deficiencies a concern for somebody who is just trying PB diet? What are the red flags?

Ryan Andrews:
If someone is experimenting with 100% PB beyond few days, I have check-list in my head about potential deficiencies. Before supplementing with various vitamins, it is best to have blood test results and supplement based on that.
Get most of your nutrition from a variety of whole foods. Beyond that, focus on getting adequate protein, B vitamins (especially B12), vitamin D, essential fatty acids, and minerals such as magnesium, iodine, zinc.

Struggling with digestion – ideas and strategies

Ryan Andrews: 
How are you transitioning? Is it a sudden switch from no legumes and vegetables to a lot? Switch slowly.
Some people are more suspectible to some FODMAPS. It can be overwhelming at first, but it can be an easy swap if you work with a coach. Examples.
Cauliflower -> broccoli
Cashews -> Almonds

Low-Hanging fruit adjustments

Low-hanging fruit means adjustment or changes that are very easy to make.

Brian St. Pierre: Lean into it, pick one swap that you can try instead of going all in, get bloated and start feeling bad and then say “Nah, that does not work for me”.  Over time, your priorities, needs, and preferences can change and with them your diet as well.
Ryan Andrews:
  • Swap whey protein powder for plant-based powder
  • Add legumes to your diet


  • Substitute rice milk or almond milk for cow’s milk
  • Substitute veggie patties for meats
  • Instead of snacking chips or pretzels, have an orange or an apple
  • Add vegetables, especially green leafy vegetables to your diet