Brian St. Pierre

Meet the Experts

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. He holds a master’s degree in Food Science and Human Nutrition from the University of Maine.

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.

During his time at Precision Nutrition, St. Pierre has provided nutrition coaching and performance meal planning to US Open champion Sloane Stephens and a host of other professional and Olympic athletes. He’s also served as a nutrition consultant for the NBA’s San Antonio Spurs and Brooklyn Nets and the NFL’s Cleveland Browns.

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.

A leading expert in teaching nutrition coaching skills to fitness professionals, St. Pierre has presented hundreds of workshops and trainings in five countries and 17 U.S. states. He’s been featured in US News & World Report, Men’s Health, Men’s Fitness, ESPN the Magazine, Shape, Q Magazine, STACK, and Testosterone Magazine and his insights have been included in stories on,, BuzzFeed, and more.

Twitter: @bspnutrition
LinkedIn: brian-st-pierre-ms-rd-cscs-b2a19519b

Articles by Brian St. Pierre, MS, RD

How to count (and track) macros for fat loss, muscle gain, and better health

If you don’t like counting calories, this might be a shortcut.

‘How much water should I drink?’

The “8 cups of water a day” rule has a few exceptions.

Woman in athletic clothing walking outside using her fitness tracker.

Health and fitness trackers: Do they help… or hurt?

Worksheets are still around for a reason.

Man sprinkling salt on top of meats and vegetables cooking on an outdoor grill.

The carnivore diet: Can it really transform your health?

Will the carnivore diet work for you (or your clients)? We look at the evidence.

Close-up of various hands representing how to use hands to gauge food portions.

Every question about PN’s hand-portion method—answered.

How to handle alcohol, mixed foods, soups, and more.

Ketogenic diet-friendly sources of protein, carbs and fats.

‘What should I eat?!’ The keto diet edition. [Infographic]

Use this guide to build a balanced keto-friendly eating plan in minutes.

Fully plant-based diet-friendly sources of protein, carbs and fats.

‘What should I eat?!’ The fully plant-based diet edition. [Infographic]

This article answers the question, “What can I eat on a fully plant-based diet?!”

Closeup of a woman resting against a window with the sun shining on her face.

“Should I take vitamin D?” Here’s what the science says.

Seems like everyone's taking vitamin D… but should they?

Paleo-friendly sources of protein, carbs and fats.

‘What should I eat?!’ The Paleo diet edition. [Infographic]

How to choose “Paleo foods” that are right for your body, goals, and taste buds.

Mediterranean diet-friendly sources of protein, carbs and fats.

‘What should I eat?!’ The Mediterranean diet edition. [Infographic]

Learn how to make Mediterranean diet choices that are “just a little bit better.”

Closeup of an outstretched hand holding a phone with the Precision Nutrition Weight Loss Calculator displayed on screen.

Precision Nutrition’s
Weight Loss Calculator

This weight loss calculator (based on the NIH Body Weight Planner and adapted from research collected at the National Institute of Diabetes and Digestive and Kidney Diseases), factors in how your metabolism really works to predict how long it’ll take to reach a particular weight loss goal.

Plant-based sources of protein, carbs and fats.

‘What should I eat?!’ How to choose the best vegetarian and plant-based foods for your body. [Infographic]

Start making better choices, whether you’re browsing the grocery store aisles, cooking a homemade meal, or ordering from a menu.

Closeup of hands cracking an egg into a pan on the stove.

The Paleo diet: Your complete how-to guide.

Find out if the Paleo Diet is right for you.

Man spooning food from a bowl onto a plate at the kitchen table.

Plant-based nutrition: A complete guide for vegetarians, pescatarians, flexitarians, and more.

This article will clear up the confusion around plant-based diets.

Collage of question marks in speech bubbles against a yellow background.

Best diet quiz: How’s that diet REALLY working for you?

This 16-question quiz helps you figure out whether a dietary approach is a good fit—allowing you to feel good, perform in the gym, eat out, and remain connected to friends and family.

Woman eating a bowl of fruits.

Carb cycling: Is this advanced fat loss strategy right for YOU?
(Take the quiz.)

Here’s everything you need to know about this popular nutrition strategy.

Horizontal chart of different potato and sweet potato meals shown from eat more often on the left to eat less often on the right.

Sweet potatoes vs. potatoes: Which are really healthier? [Infographic]

Sweet potatoes vs. potatoes: A nutritional debate fueled by misinformation, baseless ‘superfood’ obsessions, and carbohydrate phobias. Here’s how these tubers compare — and why both deserve a place in your diet.

Male athlete with a prosthetic leg in an explosive running position on an outdoor running track.

The new rules of sports nutrition: This could revolutionize the way you coach athletes.

Sports nutrition is about more than biochemistry and advanced training plans. Here’s how to help your clients get to the next level.

PN Nutrition Calculator displayed on two tablets.

The Ultimate Macro Calculator

Do you want to lose weight? Gain muscle? Improve health? Boost performance? This free calorie, portion, and macro calculator from Precision Nutrition can help you achieve the results you want.

Disappointed man wearing swim trunks holding a fitness magazine.

Fat loss hacks!?!? 10 charts show why you don’t need them.

Most “diet hacks,” “fast fixes,” and “easy solutions” make fat loss even harder than it needs to be. Here’s what you can do instead.

Fully plant-based, vegetarian and pescatarian protein sources to eat more of.

Protein for plant-based eaters: How to choose the best sources.

Plant-based protein is an important part of any vegan, vegetarian, or plant-forward diet. Find out which high protein foods are best for plant-based eaters.

Eight vertical bar graphs. Each graph shows how many pounds lost, percent body weight lost, total inches lost, or inches from waist lost based on the percentage of consistency.

Nearly 1 million data points show what it REALLY takes to lose fat, get healthy, and change your body.

We analyzed a year’s worth of data from 1,000 nutrition coaching clients to find out how much effort it really takes to make meaningful change—to your body, your health, and even how you feel about yourself. This body transformation research might shift your thinking about weight loss and health improvement forever.

Man pressing cellphone between ear and shoulder, holding a notebook looking confused.

Meal plans usually suck.

Lots of people looking to improve their eating think meal plans are the answer. The only problem? Meal plans usually suck... and they rarely last. So, instead of prescribing yet another doomed eating regimen, check out these 6 ways to transform any diet in a sustainable way.

Chart showing the relationship between blood glucose levels and time. Minutes is on the x-axis; blood glucose (mg/dl) on the y-axis.

Carbs, insulin, and weight loss: What REALLY matters for getting the results you want

Some experts believe carbs and insulin cause weight gain. But, they say, if you eat a low-carb diet, you’ll keep insulin levels low—and lose weight fast. Learn the truth… and find out what matters most for losing fat.