Most people think aging is about hormones, wrinkles, or a “slowing metabolism.” But according to the scientist who first described sarcopenia, the real driver behind metabolic decline is muscle loss.
In a powerful conversation between muscle-first aging advocate JJ Virgin and Dr. Bill Evans, Adjunct Professor at UC Berkeley and a leading researcher in human nutrition and muscle physiology, one message becomes clear: muscle is the foundation of strength, metabolism, and long-term independence.
If you care about muscle, this is the conversation that changes everything.
Who Is JJ Virgin and Why She Champions Muscle-First Aging
JJ Virgin is a triple-board certified nutrition expert and four-time New York Times bestselling author known for redefining aging as something to own, not endure. Her philosophy, “Muscle Changes Everything,” challenges outdated weight loss models and shifts the focus toward strength, metabolic health, and body composition.
Rather than chasing a lower number on the scale, JJ teaches that what your weight is made of matters more than the number itself. Lean muscle is not aesthetic. It is protective.
In her discussion with Dr. Evans, she reinforces a simple but powerful truth: the muscle you build today is the independence you keep tomorrow.
Dr. Bill Evans: The Scientist Who Described Sarcopenia
Dr. Bill Evans was among the first researchers to describe sarcopenia, the age-related loss of muscle mass. His early work at the USDA Human Nutrition Research Center at Tufts University helped establish the link between muscle loss, reduced strength, and increased risk of disability.
His research shows:
- Muscle loss drives reduced metabolic rate.
- Strength is strongly associated with function and health outcomes.
- Muscle mass is predictive of mobility, fracture risk, and even mortality.
As Dr. Evans explains, muscle is metabolically expensive tissue. The less muscle you have, the fewer calories your body needs. That is why metabolism slows with age. It is not inevitable. It is physiological.
Even more compelling, his lab demonstrated that individuals in their 90s can increase fast-twitch fiber size with resistance training. Muscle is adaptable at any age.
Sarcopenia, Muscle Protein Synthesis, and the Aging Metabolism
Muscle loss begins earlier than most people realize. Around age 30, we begin losing motor units, especially fast-twitch fibers responsible for strength and power. Add sedentary habits, hormonal shifts, and inadequate protein intake, and the decline accelerates.
Dr. Evans emphasizes that muscle protein synthesis is central to preserving lean tissue. When protein synthesis declines, muscle mass declines. During calorie restriction, especially in older adults, protein synthesis drops significantly. That is why weight loss without adequate protein and resistance training can be so damaging.
Older adults also require higher protein intake to stimulate muscle protein synthesis effectively. Yet many fall short, especially women attempting to reduce calories.
Muscle loss is not just about appearance. It affects insulin sensitivity, walking speed, balance, and the ability to remain independent.
Fortetropin and Myostatin: A New Frontier in Muscle Preservation
During their conversation, JJ shares her experience with Fortetropin, the active ingredient in YOLKED. Intrigued by emerging research, she began using it herself and noticed measurable changes in lean mass.
Dr. Evans and his team conducted research at UC Berkeley examining Fortetropin’s effect on muscle protein synthesis in older adults. In a randomized, controlled study, they observed a significant increase in muscle protein synthesis in participants receiving Fortetropin compared to a calorically matched control.
Fortetropin is derived from fertilized egg yolk and has been shown in research to support healthy myostatin regulation. Myostatin is a protein that acts as a negative regulator of muscle growth. When myostatin activity is elevated, muscle growth is limited. Supporting healthy myostatin balance may help create a more favorable internal environment for muscle preservation.
In addition to studies in healthy older adults, research models suggest Fortetropin may help maintain protein synthesis even during periods of caloric restriction. That is particularly relevant in an era where GLP-1 medications and weight loss protocols are common.
Muscle preservation during weight loss is critical. Once lost, muscle is difficult to regain, especially in adults over 60.
Why YOLKED Matters in a Muscle-First Strategy
YOLKED is formulated with Fortetropin to support lean muscle alongside resistance training and adequate protein intake. It is not a replacement for lifting weights or eating well. It is a strategic complement.
Aging is not passive. It is a negotiation between biology and behavior.
Resistance training challenges the muscle. High-quality protein fuels it. Fortetropin supports the internal signaling environment that helps preserve it.
Together, they form a comprehensive muscle-first approach.
If metabolism, strength, mobility, and independence matter to you, muscle cannot be optional.
Build it.
Feed it.
Support it.
Stay YOLKED.