Hey,
Walk into any gym and you'll see the same split: people trying to lose fat are on the treadmill. People trying to build muscle are lifting weights.
"You have to do cardio to burn fat."
It's one of the oldest beliefs in fitness. And the science says it's only half the story.
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THE CALORIE BURN ARGUMENT
On the surface, cardio wins. A 30-minute run burns more calories than a 30-minute weights session. That's just physics. Your heart rate is higher, you're moving continuously, and the energy cost is greater in the moment.
This is why most people default to cardio when they want to lose weight. More sweat, more calories burned, faster results. Right?
Not quite.
WHAT HAPPENS AFTER YOU STOP
Here's where resistance training changes the equation.
After a weights session, your body continues burning calories at an elevated rate for hours. This is called EPOC (excess post-exercise oxygen consumption). Recent research found that resting oxygen consumption was still significantly elevated 14 hours after a resistance training session. That's additional energy your body uses to recover, repair muscle tissue, and restore balance.
But the bigger effect isn't the afterburn. It's what happens over weeks and months. Resistance training builds and preserves muscle mass. Muscle is metabolically active tissue. The more you carry, the higher your resting metabolic rate, meaning you burn more calories doing absolutely nothing.
Cardio burns calories while you do it. Weights change how many calories your body burns all day.
WHAT THE RESEARCH ACTUALLY SHOWS
A 2025 meta-analysis published in the Journal of the International Society of Sports Nutrition compared aerobic, resistance, and combined training for fat loss. The findings:
Aerobic training produced slightly more total weight loss on the scale
But resistance training participants gained muscle while losing fat, meaning their body composition improved even when the scale didn't move as much
Combined training (both cardio and weights) produced the best overall results for fat loss and metabolic health
A separate 2025 review confirmed that resistance training is the most effective strategy for preserving lean mass during a calorie deficit. When you diet without lifting, up to a third of the weight you lose can come from muscle. That's the opposite of what you want.
THE MYTH: "CARDIO IS FOR FAT LOSS, WEIGHTS ARE FOR MUSCLE"
This framing is wrong because it treats them as separate goals. Fat loss and muscle preservation are the same goal if you want to actually look and feel better, not just see a smaller number on the scale.
Losing 10kg of fat and 3kg of muscle is a very different result from losing 10kg of fat and gaining 1kg of muscle, even though the scale tells a completely different story in each case.
If you only do cardio while dieting, you risk becoming a smaller, softer version of yourself with a slower metabolism. If you lift while dieting, you keep the muscle, keep the metabolic rate, and lose mostly fat.
WHAT I TELL MY CLIENTS
If you're short on time and have to pick one: lift weights. Add walking on top for general health and extra calorie burn. That combination beats hours on the treadmill for long-term fat loss every single time.
A simple framework:
3 to 4 resistance training sessions per week
Daily walking (8,000 to 10,000 steps)
Cardio if you enjoy it, not because you have to
The best exercise for fat loss is the one that protects your muscle while you're in a deficit. That's resistance training. Everything else is a bonus.
Got a question about training, fat loss, or how to structure your week? Hit reply!
See you next week,
Gabriel Nutrition Coach & Founder | gbMeals | The Fundamentals