The Lean Pork Discovery: How Meat Type Affects Post-Workout Muscle Growth

What you eat after lifting matters—but new research suggests what type of meat matters more than we previously thought. A groundbreaking 2025 study from the University of Illinois Urbana-Champaign has revealed surprising findings about how different pork preparations affect muscle protein synthesis (MPS) after weight training [^1].

The Study

Published in the American Journal of Clinical Nutrition, researchers examined how 16 young, physically active adults responded to weight training when eating different types of pork burgers containing the same amount of protein. The study used a clever crossover design where participants performed leg presses and leg extensions, then consumed one of three meals:

• High-fat pork burger (roughly 30% fat)
• Lean pork burger (roughly 7% fat)
• Carbohydrate drink (control)

Using isotope-labeled amino acid infusions and muscle biopsies, researchers could precisely track how quickly amino acids were incorporated into muscle tissue.

The Surprising Results

Here's what shocked the research team:

• Lean pork produced the highest MPS rates after weight training
• High-fat pork "blunted" the muscle-building response—participants showed only slightly better MPS than those who drank a carbohydrate sports beverage
• The lean pork group showed larger increases in blood amino acid concentrations, including essential amino acids

Lead researcher Dr. Nicholas Burd noted: "For some reason, the high-fat pork truly blunted the response. In fact, the people who ate the high-fat pork only had slightly better muscle-building potential than those who drank a carbohydrate sports beverage after exercise." [^1]

But Wait—Didn't Whole Eggs Beat Egg Whites?

This seems to contradict earlier findings from the same lab. Previous research showed that eating whole eggs after training led to greater MPS than consuming the same protein from egg whites alone. Similarly, salmon produced a stronger muscle-building response than a processed blend with identical nutrients.

So what's going on?

Dr. Burd offers a potential explanation: Processing matters. The ground pork patties required grinding and mixing lean meat with fattier cuts—processing that may have affected digestion kinetics. "It could be that processing the ground pork patties... affected the kinetics of digestion," he explained [^1].

This suggests:

• Whole, unprocessed foods appear to be better stimuli for MPS
• Processing methods may alter how nutrients are absorbed
• The fat benefit seen with eggs and salmon might not apply to all meat forms

Practical Implications

Before you ditch all dietary fat, consider these nuances:

What This Study Supports

• Lean protein sources after training may optimize the MPS window
• Whole, minimally processed meats likely outperform processed options
• Protein quantity still matters—all pork groups outperformed carbs

What Needs More Research

• The fat-MPS relationship may be food-specific, not universal
• Processing methods (grinding, emulsification) may be as important as fat content
• Long-term studies examining actual muscle growth (not just MPS rates) are needed

The Bigger Picture

Dr. Burd emphasizes that exercise remains the dominant driver of muscle growth: "Most of the muscle response is to weight-training, and we use nutrition to try to squeeze out the remaining potential." [^1]

This research adds to a growing understanding that not all protein sources are equal—even when macronutrient profiles appear similar. For athletes optimizing hypertrophy:

• Prioritize whole, unprocessed protein sources when possible
• Consider lean options in the post-workout window
• Don't fear fat entirely—it may benefit MPS in whole-food contexts (eggs, salmon)
• Processing matters—minimally processed beats highly processed

Conclusion

The 2025 pork study challenges blanket assumptions about dietary fat and muscle building. While previous research suggested whole eggs and salmon enhanced MPS compared to leaner alternatives, this study found lean pork outperformed fattier pork—possibly due to processing methods.

The takeaway? Whole foods trump processed ones, but the fat-MPS relationship is more complex than previously thought. For now, prioritize lean protein post-workout from minimally processed sources, and don't overcomplicate it—training hard remains the primary driver of muscle growth.

---

References

[^1]: Zupančič, Ž., et al. (2025). Post-exercise muscle protein synthesis responses to pork burgers varying in fat content. American Journal of Clinical Nutrition. University of Illinois Urbana-Champaign.