You want to lose fat, but the gym offers two main paths: the treadmill or the squat rack. For decades, lifters, coaches, and athletes have debated which one is truly better for shedding body fat while holding onto precious muscle.
Some swear by high-volume resistance training, citing the afterburn effect (EPOC). Others argue that nothing torches calories like steady-state cardio. And a third group hedges their bets, doing a bit of both.
Finally, a massive new systematic review and meta-analysis published in 2025 gives us the clearest answers yet. Researchers compiled the results of 36 randomized controlled trials to definitively compare aerobic training, resistance training, and doing both in the same week. Let's break down what they found and what it means for your training.
The Contenders: Cardio vs. Weights vs. Both
This meta-analysis, which included data from over 1,500 participants, looked at three distinct training styles:
- Aerobic Training (AT): Your classic "cardio," like running, cycling, or rowing.
- Resistance Training (RT): Lifting weights, using machines, or any form of strength training.
- Concurrent Training (CT): A combination of both aerobic and resistance training within the same training week.
The researchers compared how each of these approaches affected four key body composition metrics: fat mass, body fat percentage, total body mass, and fat-free mass (FFM), which is mostly muscle.
The Overall Winners for Fat Loss and Muscle Retention
When the researchers pooled all the data together, a clear picture emerged. Here’s the head-to-head breakdown:
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For Losing Fat Mass: Both Aerobic Training (AT) and Concurrent Training (CT) were significantly better than Resistance Training (RT) alone. There was no meaningful difference between AT and CT, meaning cardio alone was just as good for fat loss as doing cardio and weights.
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For Losing Total Weight (Body Mass): Aerobic Training (AT) was the undisputed champion. It led to significantly more total weight loss than both RT and CT.
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For Keeping Muscle (Fat-Free Mass): This is where things get interesting. Resistance Training (RT) was significantly better at preserving FFM than Aerobic Training (AT). Concurrent Training (CT) landed right in the middle, showing no statistical difference when compared to either AT or RT. This suggests that adding lifting helps offset the potential muscle loss from a cardio-heavy program.
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For Body Fat Percentage: Surprisingly, there were no significant differences between any of the three training styles.
At first glance, it seems like cardio is best for weight and fat loss, while lifting is best for muscle. But the story doesn't end there. The most important finding was hidden in a sub-analysis.
The Game-Changer: It's Not the Method, It's the Workload
The researchers performed a crucial sub-analysis, looking only at the 12 studies where the total workload was matched between groups. This means the researchers tried to make the total energy expenditure (calories burned) or session duration equal for the cardio, lifting, and concurrent groups.
When the workload was equated, a fascinating thing happened: all the differences disappeared.
That's right. When total work was the same, there were no significant differences between AT, RT, and CT for changes in fat mass, body mass, body fat percentage, or even fat-free mass.
This is the key takeaway: the type of exercise you do for fat loss is far less important than the total amount of work you perform. Cardio often wins in the overall analysis simply because it's easier to achieve a higher energy expenditure in a continuous 60-minute session compared to a 60-minute lifting session that includes rest periods.
Practical Takeaways for Your Program
So, what should you actually do in the gym? This study provides clear, evidence-based guidance.
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If Pure Fat Loss is Your Only Goal: Pick the modality that allows you to burn the most calories consistently. For most people, that will be some form of aerobic training. But as the work-matched data shows, if you can create the same energy deficit by lifting, you'll get the same fat loss results.
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If You Want to Lose Fat AND Keep Muscle (The Recomp): Concurrent Training (CT) is your best bet. The overall data shows that while cardio is great for energy expenditure, adding resistance training is crucial for signaling your body to hold onto muscle mass during a deficit. CT gives you the best of both worlds.
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Don't Expect Miracles Overnight: The analysis found that significant differences between training types only appeared in studies lasting 10 weeks or longer. In shorter interventions (<10 weeks), all three methods produced similar results. This underscores the importance of consistency and patience.
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Don't Sweat the Schedule: The study looked at whether doing cardio and lifting on the same day vs. different days made a difference. While there was a slight signal that same-day CT was better for fat loss than RT, the authors cautioned that the data was limited. The most practical advice is to schedule your training in a way that you can stick to consistently.
The Bottom Line
This powerful 2025 meta-analysis helps settle an old debate with a nuanced answer. While aerobic training is a highly efficient tool for driving energy expenditure and weight loss, resistance training is superior for preserving muscle.
For the average lifter or athlete looking to optimize body composition, the answer is clear: do both.
Concurrent training provides the calorie-burning benefits of cardio while protecting your hard-earned muscle. The ultimate driver of fat loss is creating a sustained energy deficit, and the best training program is the one that helps you achieve that while meeting your specific goals for strength and muscle retention.
Reference:
Lafontant, K., Rukstela, A., Hanson, A., Chan, J., Alsayed, Y., Ayers-Creech, W. A., Bale, C., Ohigashi, Y., Solis, J., Shelton, G., Alur, I., Resler, C., Heath, A., Ericksen, S., Forbes, S. C., & Campbell, B. I. (2025). Comparison of concurrent, resistance, or aerobic training on body fat loss: a systematic review and meta-analysis. Journal of the International Society of Sports Nutrition. https://pubmed.ncbi.nlm.nih.gov/40405489/