Many people train to either lose weight or build muscle, so with these specific training goals in mind it is important to understand the impact of the different types of training and nutrition in meeting these goals.
In this excerpt from Elite Physique: The New Science of Building a Better Body we explore the core training principles you’ll need to know to build muscle or lose fat.
Muscle building vs. fat loss
Almost any resistance training program can both burn fat and build muscle. Consider three intelligently designed resistance training programs. Let’s say each of these three programs has a different emphasis:
- Training plan 1 emphasizes heavy loads (3-5 sets of 3-5 reps).
- Training plan 2 emphasizes moderate loads (3-4 sets of 6-12 reps).
- Training plan 3 emphasizes lighter loads (3-4 sets of 18-20 reps).
If you simply look at the sets and reps, and don’t know anything else about the programs, you could say with some confidence what each program is designed to achieve. The goal of training plan 1 is to build maximal strength. Plan 2, using the most common hypertrophy parameters, is for someone trying to increase muscle size. And plan 3, with its high volume (up to 80 reps per exercise), would be best for fat loss.
But what if you learned that every set in plan 3 is to be taken to momentary muscular failure to create metabolic stress, a potent stimulus for hypertrophy (Schoenfeld 2010)? Or that plan 1 includes lots of single-joint exercises for muscles that wouldn’t typically be emphasized when the goal is pure strength? Or that plan 2 has relatively short rest periods and thus limited recovery between sets, which wouldn’t be optimal for hypertrophy? Wouldn’t that change your sense of what each program was designed to achieve?
The truth is, any of the three can be a muscle-building or fat-burning program. Training with heavy loads induces greater growth of type II muscle fibers, or equal growth of type II and type I fibers, mainly by myofibrillar hypertrophy. Training with lighter loads for a high volume or to momentary muscular failure causes more growth in type I fibers and might stimulate sarcoplasmic hypertrophy (Haun et al. 2019). What matters most is this:
- All muscle fiber types can grow with the right type of training.
- Your daily nutrition is the difference maker. If you consistently consume 500 calories a day above your maintenance level, you’ll gain muscle with any of the three programs. If you eat 500 calories below your maintenance level, you’ll lose fat with the same programs.
Training for fat-loss
A fat-loss program needs a few modifications because training and eating to burn fat requires a caloric deficit, which imposes stress on your immune system. With too much overall stress, you won’t be able to maintain optimal levels of testosterone and other anabolic hormones (Fry and Kraemer 1997; Schoenfeld et al. 2020). The modifications are as follows:
- Less volume: For example you’ll do four rounds of a circuit instead of five or more.
- Less intensity: You’ll stop each set one or two repetitions short of failure to avoid excessive muscle damage (another form of stress).
- Fewer exercises: Fat-loss workouts often have three or four multijoint exercises instead of five or more.
- Shorter rest periods: With 30 to 45 seconds of rest between each exercise in a circuit, instead of 2 to 3 minutes, you’ll elicit a larger cardiorespiratory response (Alcaraz, Sanchez-Lorente, and Blazevich 2008).
- More metabolic work: Each workout will end with a metabolic exercise (e.g., sprints or sled work) to stimulate fat loss. You’ll also do lower-intensity cardiorespiratory exercise on nonlifting days to promote fat burning and manage fatigue.
The first three changes—lower volume and intensity and fewer exercises—help you limit training-induced physical stress at a time when your body is already coping with the stress of a reduced-calorie diet. If you’re relatively new to strength training, or coming back from a long layoff, you may increase strength and muscle mass during a caloric deficit while also losing fat. But if you’re an intermediate to advanced lifter who’s been training consistently for the past few years, you may be lucky to maintain your muscle mass while losing fat. The more likely outcome is that you’ll lose some muscle along with the fat. That said, if you have a lot of fat covering strong and well-developed muscles, you will probably appear more muscular as you get leaner, even though you actually have less total muscle. It’s a trade-off most of us will gladly make when the goal is to improve your physique.
The fourth change—shorter rest periods—increases the density of your workout. In other words, you perform more work in less time. Your heart rate will increase, and you’ll breathe harder from the greater cardiorespiratory demand (Alcaraz, Sanchez-Lorente, and Blazevich 2008). You’ll also have higher levels of EPOC (excess postexercise oxygen consumption), which means you continue to burn calories at a higher rate in the hours following your workout (Greer et al. 2015). Some research suggests EPOC aids in fat loss, although probably not to the extent you often see promoted in fitness marketing (Williams et al. 2013).
Calorie burning is also the reason for the fifth change. Metabolic work is similar to strength training with limited rest periods, in that it raises your heart rate and contributes to EPOC. The low-intensity cardiorespiratory exercise on the days in between strength workouts will also burn calories and train your body to better utilize fat for fuel. So why not do only high-intensity metabolic exercise, like interval training, on nonlifting days? The goal is to limit fatigue and facilitate recovery. High-intensity exercise creates an acid load on the body that must be buffered by your kidneys, which can be stressful if you do too much of it. Simply walking at a brisk pace on those days, instead of remaining sedentary, will increase circulation, which helps your body clear the waste products left over from your strength workouts.
To summarise, strength training and both burn fat and build muscle, but nutrition can be a fundamental factor in which of the two outcomes is achieved. You can read more in Chad Waterbury’s Elite Physique.
Alcaraz PE, Sanchez-Lorente J, Blazevich AJ. Physical performance and cardiovascular responses to an acute bout of heavy resistance circuit training versus traditional strength training. J Strength Cond Res. 2008;22(3):667-671.
Fry AC, Kraemer WJ. Resistance exercise overtraining and overreaching: Neuroendocrine responses. Sports Med. 1997;23:106-129.
Greer BK, Sirithienthad P, Moffatt RJ, Marcello RT, Panton LB. EPOC comparison between isocaloric bouts of steady-state aerobic, intermittent aerobic, and resistance training. Res Q Exerc Sport. 2015;86(2):190-195.
Schoenfeld B. The mechanisms of muscle hypertrophy and their application to resistance training. J Strength Cond Res. 2010;24(10):2857-2872.
Schoenfeld BJ, Alto A, Grgic J, et al. Alterations in body composition, resting metabolic rate, muscular strength, and eating behavior in response to natural bodybuilding competition preparation: A case study. J Strength Cond Res. 2020;34(11):3124-3138.
Williams CB, Zelt JG, Castellani LN, et al. Changes in mechanisms proposed to mediate fat loss following an acute bout of high-intensity interval and endurance exercise. Appl Physiol Nutr Metab. 2013;38(12):1236-1244.