You're running on a treadmill, sweating buckets, and feeling every kilometre in your bones. You check the screen: 300 calories burned. Satisfied, you walk away, thinking you've conquered fat. Now imagine this: lifting weights for 45 minutes, going home, and still burning calories hours later while binge-watching your favourite show.
Welcome to the science of weight training, the stealthy fat-burning powerhouse that eclipses cardio when it comes to long-term results.
Says Dr. Koulsoum Houssein, MBBS, MD and Consultant at Holy Family Hospital, “Weight training increases muscle mass, which raises your resting metabolic rate (RMR) and effectively burns fat. You burn more calories even while you're at rest because maintaining muscle tissue takes more energy than maintaining fat.”
Medical research confirms this. A 2023 study by researchers from Stanford University confirmed that strength training leads to better progress in weight loss and muscle gain. In fact, An NIH-supported observational study found that women who lifted weights regularly had a 36% reduced risk for a fatal heart attack, stroke, or other cardiovascular event while men had a 14% reduced risk.
RMR And BMR Explained
At the heart of weight training's magic lies your Resting Metabolic Rate (RMR) and Basal Metabolic Rate (BMR). Think of RMR as the energy your body expends while you're lounging around, doing absolutely nothing. This energy goes toward keeping your heart pumping, lungs breathing and brain ticking. Your BMR (a component of RMR) is the bare minimum number of calories required to keep you alive.
Muscle is metabolically expensive. A pound of muscle burns about 6-10 calories per day, compared to fat, which lazily burns just 2 calories. The more muscle you have, the higher your RMR, which means you’re burning more fat even while you sleep.
The Muscle Burn Effect
Weight training is like sending your muscles to boot camp. Every lift, squat, or deadlift causes tiny tears in your muscle fibres. This might sound bad, but it’s actually great. These microtears stimulate your body to repair and rebuild the muscle, making it stronger and larger over time.
Here’s where the fat-burning magic happens: muscle repair requires energy, and your body pulls from its stored glycogen and fat reserves to fuel this process. Dr. Houssein says, "Your body uses stored glycogen to power weightlifting, and the 'afterburn effect' (excess oxygen consumption after exercise) keeps your metabolism running high for hours afterward.”
This afterburn effect [scientifically known as Excess Post-Exercise Oxygen Consumption (EPOC)] is unique to high-intensity activities like weight training. It’s like leaving the lights on in your metabolism for hours post-workout, ensuring calories continue to burn long after you’ve left the gym.
Cardio’s Limitations In Fat Burning
While cardio is excellent for cardiovascular health and burning calories during the activity itself, it lacks the muscle-building benefits of weight training. Once your run or cycling session is over, so is the majority of your calorie burn. Unlike weight training, cardio doesn’t significantly raise your RMR because it doesn’t build muscle mass.
Dr. Houssein says, “Weight training produces a long-term fat-burning environment through muscle growth and metabolic enhancement, in contrast to cardio, which primarily burns calories during action.”
Why Weight Training Is More Effective In The Long Term
Here’s why weight training takes the fat-burning trophy:
Increased RMR: Muscle requires more energy to maintain than fat, leading to higher calorie burn around the clock.
Afterburn Effect: High-intensity resistance training keeps your metabolism elevated for hours post-workout.
Body Composition Changes: Weight training reduces fat while increasing lean muscle mass, improving your body’s shape and overall metabolism.
Sustainable Results: The metabolic boost from increased muscle mass leads to long-term fat-burning benefits, even on rest days.
Tips To Incorporate Weight Training Into Your Routine
If you’re ready to ditch the treadmill and pick up the weights, here’s how to get started:
- Focus on compound movements. Exercises like squats, deadlifts, and bench presses work multiple muscle groups simultaneously, maximizing calorie burn.
- Aim for at least two to three weightlifting sessions per week, gradually increasing the intensity and weights.
- Muscle repair happens when you rest, so ensure you’re getting adequate sleep and nutrition to fuel the process.
- Cardio still has its place for heart health and endurance. Combine both forms of exercise for a balanced fitness routine.
Weight training isn’t just about building muscle and looking chiselled, it’s about building a more efficient fat-burning machine inside your body. By increasing your RMR, activating the afterburn effect and reshaping your body composition, it delivers results that cardio simply can’t match.
As Dr. Houssein says, "Weight training creates a metabolic environment that keeps burning fat long after the workout is over.”
Sources:
https://link.springer.com/article/10.1007/s00125-023-05958-9
https://www.jacc.org/doi/10.1016/j.jacc.2023.12.019
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