A surprising twist from a University of Illinois trial has nutritionists and gym-goers rethinking a common assumption: fatier meat is not always better for muscle repair. Researchers found that after resistance training, lean minced pork triggered a larger muscle-building response than a fattier version of the same meat. The result challenges simple ideas about whole foods and natural fat helping muscle growth.
What the study tested and who took part
The experiment enrolled 16 healthy, physically active young adults. Each participant completed resistance exercise sessions followed by one of three post-workout feeds.
- Lean minced pork patty
- High-fat minced pork patty
- Carbohydrate-only beverage
Muscle samples were taken five hours after eating to measure rates of muscle protein synthesis. Most volunteers repeated the trial so researchers could compare responses within the same person.
Key findings that surprised the research team
Lean pork produced the biggest boost in muscle protein synthesis. Blood tests showed larger increases in total and essential amino acids after the lean patties. Those higher amino acid levels are linked to stronger muscle-building signals.
- Lean pork led to the highest amino acid rise in the bloodstream.
- High-fat pork significantly blunted the muscle-building response.
- The high-fat group performed only marginally better than the carbohydrate beverage group.
How the trial was designed to reduce variability
The team worked for a year with the University of Illinois Meat Science Laboratory to craft test patties with precise fat ratios. To keep the samples consistent, all meat in the study came from a single pig.
Control measures included:
- Standardised exercise sessions for each participant.
- Carefully matched patties differing mainly in fat content.
- Multiple test sessions so participants served as their own controls.
Voices from the study: what the scientists said
Professor Nicholas Burd, who led the research along with graduate student Žan Zupančič, noted that the results ran counter to earlier studies where whole foods with fat outperformed leaner or processed alternatives. He highlighted the clear link between post-meal amino acid increases and the food just eaten.
“When you see an increased concentration of amino acids in the blood after you eat, you get a pretty good idea that that is coming from the food that you just ate,” Burd said, reflecting on the study’s biochemical signals.
Possible reasons why fat reduced the effect
The team suspects that the way the meat was processed — grinding and mixing fatty cuts with lean meat — may have altered digestion and slowed protein availability.
- Fat may delay gastric emptying, lowering early amino acid delivery to muscles.
- Mixing fat and lean tissue during grinding could change how proteins are released during digestion.
- Other unknown interactions between meat fats and muscle signalling remain possible.
How this compares to earlier nutrition research
Previous experiments from the same lab showed that whole eggs beat egg whites for promoting muscle growth. Salmon also outpaced some processed protein blends. Those findings suggested certain whole foods can be superior. This pork trial complicates that narrative.
Not all whole foods behave the same way once processing and fat content change. The results underline that food form and composition both matter for post-exercise recovery.
Practical implications for athletes and gym-goers
While resistance training remains the primary driver of muscle gains, nutrition can help maximise the effect. This study suggests paying attention to the fat content in post-workout protein sources.
- Consider lean cuts or lower-fat preparations soon after training.
- Avoid assuming that fattier whole meats will always be better for muscle recovery.
- Timing and protein dose still matter; these factors were controlled in the study.
Where the research was published and next steps
The findings were published in the American Journal of Clinical Nutrition. The authors call for more work to understand how meat processing and fat distribution affect protein digestion and muscle signalling.
Professor Burd emphasised that exercise is the dominant stimulus for building muscle and that nutrition aims to “squeeze out the remaining potential.” Future studies will probe whether different cooking methods, cut types, or combinations of foods change the outcome.
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Naomi is a clean beauty expert passionate about science-driven skincare and natural remedies. She demystifies ingredients and shares routines that empower readers to glow — naturally.