Unlocking Protein's Power | Dr. Jess Gwin on Essential Amino Acids and Muscle Health

**Dr. Gabrielle Lyon** (0:00)
Welcome to the Dr. Gabrielle Lyon Show. In today's episode, I sit down with nutritional physiologist, Dr. Jess Gwin. She has an amazing pedigree of experience. She currently works in the military, and she teaches us all about muscle physiology. She talks about the practical application of dietary patterns, including protein, how it impacts sleep, performance, all things related to health and wellness. What makes her research so interesting is that it is translatable to humans. She looks at real humans. She helps with intervention studies. And this episode will be very interesting because it's laid out clearly, actionable steps for you to do, to take current research into your real life.
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Dr. Jess Gwin, welcome to the podcast.
I am really excited to have this conversation. You are a whiz on all things protein, essential amino acids. And I first heard about you through our mutual friend, Dr. Nick Beringer, Ranger dietitian. Welcome to the show.

**Dr. Jess Gwin** (1:40)
Thank you. I'm so excited to be here. I love talking about all things protein. It's really been a huge part of my life for the past decade. So it's a pleasure to be here. Thank you.

**Dr. Gabrielle Lyon** (1:51)
Yes, certainly. And I would love for you to catch us up to speed. I know that you have worked very closely with someone named Dr. Heather Leidy. She is truly extraordinary in her work. The contribution of her work really is, I mean, it's multifactorial, but really this idea of protein, protein first, protein effect on the brain.
But before we talk about all that, just catch us up to speed a little bit about where you've come from and what you're doing.

**Dr. Jess Gwin** (2:19)
Absolutely. So I'll just start from the beginning. And the origin story really does start with Heather. But a few years before that, I really found this interest in nutrition and exercise science. I was a former athlete at the University of Missouri. And at that time, I was really just interested in how do I improve my performance. So naturally, coursework aligned with that quite well. So fast forward through undergrad and I reached that time where you're transitioning out of your undergrad studies and trying to really pursue a next step. And there became an opportunity to become a lab technician at the University of Missouri in their nutrition and exercise physiology department. And it was a really unique opportunity because that department pairs both nutrition and physical activity. They really understand at that time that they were the king and queen kind of this health perspective. And it happened to be that Heather had an opening as a lab technician, so I really got my start in this research space from the ground up, learning how to build participant folders and paperwork, et cetera. And that love for research kind of grew over that next 10 months, where she allowed me to get really involved in her day-to-day full feed intervention studies. At that time, we were working a lot with middle-aged women looking at appetite control and satiety, so eating behaviors. For those of you unfamiliar, that's hunger, fullness, feelings of food reward, how full are you, and when do you stop eating a meal? And so her work really has focused on, across the breadth of her career, using dietary protein in healthful interventions to improve appetite control and weight management.
From there, I fell in love with the research process and decided I wanted to pursue a Ph.D. in nutritional sciences and had the extraordinary opportunity to stay on in her laboratory. And we really, just over the next four years, continued to focus on those full-feed interventions using high-quality proteins and really trying to better understand how consuming high-quality protein across the day and across different meals may impact an individual's appetite response. It included questions of subjective nature, where we ask an individual what's your immediate feeling of response, or immediate feeling of hunger or fullness. We also looked at the blood work, looking at circulating markers of hunger and fullness through hormones that are derived from the gut and feed back into the brain.
We also did some functional brain imaging at that time, trying to pair this subjective measure of how does someone feel, how is their body responding, and then what does that look like in the brain's response. We use pictures, for example, of animals and foods. Both are really rewarding and pleasurable, but when an individual is in a functional MRI scan, and you show them a picture of food, there is an area of their brain that is associated with hunger and fullness, food reward, that lights up or doesn't light up. We were testing whether the manipulation of protein impacted that food reward region of the brain.