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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

Person taking weight loss medication.

Ozempic for weight loss: What coaches (and clients) need to know about GLP-1 drugs

GLP-1 drugs offer an opportunity for clients to get better results—and for coaches to flex their skills.

The benefits of saunas and ice baths: A zero-hype guide for boosting heart health, mood, and longevity

Welcome to the gateway drug for health and wellness.

Older person building muscle

The new science of muscle: The big impact strategies you need to do (and the fluff you can ignore)

Muscle size, strength and power tends to decline with age. Here’s what to do.

The Ultimate Sports Nutrition Guide for Athletes and Coaches

Get a free PDF nutrition guide for your sport.

The Deep Health Assessment: How’s your health… REALLY?

Physical health isn’t the only kind of health.

Body Fat Calculator & Body Fat Percentage Calculator

Find out your body percentage and how it affects your health.

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.

Nutrition and mental health: What (and how) to eat

No one food or supplement is king.

The traffic light eating method

The traffic light eating method: Diet goldmine—or landmine?

How to eat nutritiously, enjoy your meals, and feel in control around food.

Photo of table full of junk foods, including chips, pretzels, cheesy puffs, caramel corn, and more.

How to eat junk food: A guide for conflicted humans

No foods are off limits!

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.

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.

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.