One reason you might strength train is to build muscle, but many people have the goal of losing body fat too. If you have too much body fat covering your muscles, you won’t see the results of your muscle-building labors. If you do cardio for fat loss with the idea that strength training doesn’t significantly reduce body fat, think again. A new study shows that it does, and scientists now know the mechanism.
Strength Training for Fat Loss
A new study published in the journal FASEB identifies a mechanism by which strength training converts your body into a fat-burning machine. When you work your muscles against resistance, there’s a lot going on at the molecular level. Muscle cells communicate with tissues, such as fat tissue, via tiny structures called extracellular vesicles. These lines of communication allow cells to send messages back and forth to each other.
Research in mice and humans shows that in response to strength training, muscle cells send out extra cellular vesicles that tell your fat cells to burn more fat. No aerobics required! So, muscle cells and fat cells communicate in a way that helps the latter burn more fat. It’s unclear how heavy you must lift to maximize fat loss but lifting heavier would seem to be more favorable. At the very least, you would need to use progressive overload to keep the communication between fat and muscle tissue strong.
Other Mechanisms by Which Strength Training Increases Fat Loss
Strength training reduces body fat in other ways too. When you work your muscles against a challenging resistance it creates an afterburn. The afterburn is the extra energy your body must expend to return to baseline after a tough workout. The more intense the workout, the greater the afterburn.
Strength training raises your body temperature, creates muscle tears, and changes the pH of your blood. Muscles require energy resources to repair and rebuild themselves. This means your body will burn more fat to provide energy for repair work. The extra energy your body expends to restore baseline is the afterburn. Some studies suggest that the additional calorie burn lasts up to 24 hours.
Plus, strength training increases the size of your muscles. Larger muscles are more metabolically active and use more energy. This effect is smaller than what scientists originally thought but building more muscle does modestly boost your resting metabolic rate. The effect of the afterburn and gaining more muscle is small but not insignificant. For example, if you gained 4.5 pounds of muscle mass, you’re burning around 50 additional calories per day.
Do You Still Need Cardio to Slim Down?
A 30-minute moderate-intensity cardio session burns more calories than 30 minutes of weight training while you’re doing it, but an intense weight-training session will burn more calories after the session is overdue to the afterburn. Plus, you get the shorter-term benefits of the afterburn and the longer-term benefits of adding more metabolically active muscle to your frame.
Cardio offers other benefits though, particularly for heart health. It builds stamina, which can help you with weight training too. So, it’s still something you should include in your routine. However, some people overemphasize cardio because they believe it’s a better approach to slimming down, but having more muscle helps you better maintain the fat you lose. To lose body fat, you may find it more beneficial to cut back on cardio sessions and replace some of them with strength training.
You can also get an afterburn by increasing the intensity of cardio. Rather than exercising at a moderate intensity, add interval training to your routine. Interval training alternates between lower intensity exercise periods and higher intensity periods of exercise. If you run or jog for exercise, you might jog for 1 minute and then sprint for 30 seconds and keep alternating.
Focus More on Compound Strength Training Exercises
If you’re trying to maximize fat loss through strength training, work as many muscles as you can with each exercise. Exercises that work multiple muscle groups simultaneously are called compound exercises. Compound exercises that are the biggest calorie burners are deadlifts, squats, push-ups, pull-ups, and lunges. Doing strength training exercises circuit style also increases the afterburn.
It’s 80% Nutrition
Keep strength training and get the exercise portion of your fat loss program right but focus on nutrition too. The saying that fat loss if 80% nutrition and 20% exercise is on target. Muscles grow in between workouts as the muscle repair and rebuild to become bigger stronger. That requires adequate calories and protein.
Good nutrition gives you the energy to power through your workout and adequate calories and protein keep your body in an anabolic state for muscle hypertrophy. Eat some protein at every meal and get 20 to 30 grams of protein within an hour of your workouts.
Skip the processed foods that only cause you to feel hungry again a few hours later. Choose whole, fiber-rich foods and high-quality sources of protein from natural food sources. Don’t depend too much on protein bars and shakes.
The Bottom Line
If you’re trying to slim down, strength training can help you get there in more ways than one. Use progressive overload, focus on compound exercises, and don’t ignore the nutrition part of the equation. Be consistent with your workouts and give it time. If you approach your training and nutrition correctly, you should see improvements in your body composition after a few months.
References:
- Ivan J. Vechetti, Bailey D. Peck, Yuan Wen, R. Grace Walton, Taylor R. Valentino, Alexander P. Alimov, Cory M. Dungan, Douglas W. Van Pelt, Ferdinand Walden, Björn Alkner, Charlotte A. Peterson, John J. McCarthy. Mechanical overload‐induced muscle‐derived extracellular vesicles promote adipose tissue lipolysis. The FASEB Journal, 2021; 35 (6) DOI: 10.1096/fj.202100242R
- “Identifying extracellular vesicle populations from single cells.” M. Nikoloff, Mario A. Saucedo-Espinosa, André Kling, and View ORCID ProfilePetra S. Dittrich. PNAS September 21, 2021 118 (38) e2106630118; https://doi.org/10.1073/pnas.2106630118.
- “Controversies in Metabolism.” Paige Kinucan and Len Kravitz, Ph.D.
- “Benefits of Compound Exercises | 5 Reasons to Do These ….” 26 Jan. 2016, https://www.acefitness.org/education-and-resources/professional/expert-articles/5811/5-benefits-of-compound-exercises/.
- Carbone JW, Pasiakos SM. Dietary Protein and Muscle Mass: Translating Science to Application and Health Benefit. Nutrients. 2019 May 22;11(5):1136. doi: 10.3390/nu11051136. PMID: 31121843; PMCID: PMC6566799.
Related Articles By Cathe:
Which Strength Training Exercises Burn the Most Calories?
Strength-Training vs. Cardio: Which is More Effective for Weight Loss?
The Truth About Weight Loss, Body Fat Burning, and Exercise
High-Intensity Interval Training: How Intense Does It Have to Be?
Is the Afterburn Effect You Get after a Strength Workout Overrated?
Does Fasted Cardio Burn More Fat?
Related Cathe Friedrich Workout DVDs:
STS Strength 90 Day Workout Program
All of Cathe’s Strength & Toning Workout DVDs
Total Body Workouts
Lower Body Workouts
Upper Body Workouts
