Muscle Over Weight: A New Era in Obesity Care and Body Composition

Muscle Over Weight: A New Era in Obesity Care and Body Composition 

Reflections from ACSM & IDEA 2025 in Denver 

By Nina Crowley, PhD, RD, Director of Clinical Education & Partnerships, seca 

There’s a fresh pulse in the space where fitness and medicine meet—and it was beating strong at the 2025 ACSM & IDEA Health and Fitness Summit in Denver. What stood out most wasn’t just the cutting-edge science—it was the cultural evolution. 

For decades, the dominant narrative in obesity care has centered on weight loss. But this year’s standout sessions—from Drs. John Jakicic, Stella Volpe, Renee Rogers, and my own collaboration with Monica Reinagel—signaled a seismic shift. We’re moving beyond the scale to focus on muscle, metabolism, and meaningful metrics that truly reflect health. 

Redefining Obesity Treatment: Drs. Jakicic & Volpe Break the Mold 

In their session, Removing the Noise in Obesity Treatment, Drs. Jakicic and Volpe introduced the new ACSM consensus statement on physical activity for individuals with obesity. It was a powerful reminder: weight is only part of the story. 

They emphasized the long lasting health benefits of physical activity—especially when sustained over time—even without significant weight loss. Combining moderate caloric restriction with regular movement preserves function, improves metabolic health, and fosters positive momentum. 

One of the most powerful takeaways? Their shift in language—from “weight loss and regain” to “excess body weight and adiposity.” It’s more than semantics. It reflects a values-based pivot away from body shrinking toward supporting strength, function, and well-being. 

Muscle, Medications, and Misconceptions: Jakicic & Rogers Dive Deeper 

Drs. Jakicic and Renee Rogers took the conversation to the next level, addressing the intersection of GLP-1 receptor agonists, resistance training, and body composition. 

The refrain echoed across the room: “Stop calling them weight loss drugs.” 

GLP-1s like semaglutide and tirzepatide are obesity treatments, not panaceas. The critical issue isn’t how much weight is lost—but what kind of weight. 

A Shift in Focus: What’s Inside the Weight? 

• Lean mass ≠ muscle mass. Lean mass has muscle, water, organs, and other tissues. Muscle may make up only 50% of lean mass. If someone loses 25–40% of their lean mass, they could be losing significant muscle—but we need more data to confirm exact amounts. 

• Muscle Mass ≠ Muscle Quality: Not all lean mass is created equal. Losing low-quality, fatty muscle may not be harmful—but the loss of functional muscle is concerning. The distinction matters. 

• GLP-1s ≠ Magic Fixes: These medications are powerful tools- but not standalone solutions. Pairing them with structured resistance training and lifestyle support is essential. 

• Body Composition ≠ Single Metric: No method is perfect. DXA has a ~4% error margin. Over- testing or obsessing over small changes can be counterproductive. 

• People, Not Protocols: The human at the center matters most. Individual goals, preferences, and physiology must guide our care. 

Their message was clear: muscle quality and functional strength should be prioritized in clinical practice. 

 Bridging Science and Practice: Reinagel & Crowley on Preserving Muscle During Weight Loss 

In Striking the Balance: Preserving Lean Muscle During Weight Loss, Monica Reinagel and I translated these insights into actionable strategies for clinicians, coaches, and anyone working in weight management. 

From BMI to Body Composition 

We challenged the role of BMI as a primary measure of health. While it has utility in population-level data, it often misleads at the individual level. We encouraged a shift toward interpretable, accessible, and clinically meaningful body composition metrics. 

Redefining Progress 

We walked through how to assess skeletal muscle mass, lean soft tissue, and fat-free mass using DXA, BIA, and other tools—highlighting the pros, cons, and pitfalls of each. Most importantly, we reminded attendees that data without context can replicate the same harm as over-reliance on the scale. 

GLP-1s in the Real World 

We addressed the predictable lean mass loss associated with significant fat loss during medication use. Preserving function and autonomy, rather than simply preserving mass, should be the clinical priority. 

Protein: More Than a Number 

We dug into practical nutrition science: 

• The RDA is a floor, not a ceiling. 

• 1.2–2.0g/kg/day is often more appropriate for older adults or those in a deficit. 

• Timing and source matter—complete proteins are helpful, but so is accessibility and sustainability. 

Coaching with Compassion 

In our behavioral section, we reinforced a foundational truth: change begins with trust. Compassionate communication, inclusive language, and focus on non-scale victories are vital. Body composition data can empower these conversations but keep the focus on the whole person.  

A Cultural Shift You Could Feel 

Throughout the summit, the energy was unmistakable: 

• Fitness professionals ready to collaborate with healthcare providers. 

• Clinicians eager to talk about protein, resistance training, and motivation. 

• A shared consensus: we can do better than BMI and body weight alone. 

It’s not just about changing metrics. It’s about changing mindsets. 

Final Takeaways for Healthcare Professionals 

As we translate insights into action, here’s what I encourage all of us in healthcare to carry forward: 

1. Look beyond weight. Assess muscle, function, and how people feel. 

1. Use medications wisely. Always contextualize with lifestyle and movement. 

1. Support with protein. Tailor quantity and quality to the individual. 

1. Prescribe exercise as empowerment. It’s a tool for autonomy, not a punishment. 

1. Center compassion. Relationships and trust are the foundation of sustained change. 

Muscle is the Messenger of Health. 

Strength is the signal of progress. Compassion is the catalyst for change. 

If you were at #HFS25, I’d love to hear what resonated most with you. And if you missed it—don’t worry. This movement is just getting started.