If you ask most people the best way to burn fat, they'll normally say increase your cardio workouts. However, lifting weights can, in some cases, actually be a more effective fat burning strategy than cardio alone. This may seem counter-intuitive and it does of course depend on the type of weight training as well as the amount of cardio, but resistance training really does help to burn fat. Let's have look at the reasons why.
Not any old weight training, but strength-based stop-start resistance training will burn through your muscular glycogen (the body's sugar storage molecule) very quickly. Then, when you refill the glycogen levels with food post-training, if you've done a hard workout, the blood sugar won't hang around in the blood stream as long. Over time your insulin sensitivity will improve, so your body will get better at using sugar for energy in the muscles, rather than converting it into fat.
A study in 2002 (1) showed that the excess post-exercise oxygen consumption (EPOC), which directly affects metabolism, increases for up to 38 hours post-exercise when resistance training was involved. This EPOC effect means you'll be using more calories post-exercise even if you're resting, so your basal metabolic rate effectively increases. This is a great step in making yourself a fat burning machine, especially if you never exceed 38 hours between workouts. Because traditional steady cardio training is normally very efficient your EPOC after steady cardio will be lower. However this doesn't apply if your cardio training is HIIT. Like weight training, this will also increase your EPOC as we discussed in our last blog "What is HIIT cardio?".
So as well as the short term increase in metabolic rate, you can actually rewire your metabolism by building muscle.
As muscle is very energy expensive, it requires calories to maintain. When you compare this to fat, which is a storage medium so requires no calories to maintain, it's easy to see how more muscular bodies will naturally burn more calories even at rest.
Muscle tissue is also fairly stable and won't deteriorate too quickly if it is maintained to a basic level. So once you have built some muscle it will continue to work for you as a fat burning engine, even when you're not training too hard. This is why men can generally get away with eating more calories than women and not gain as much weight, because they are burning more calories each day, even if they don't exercise.
Women often avoid heavy weight training due to the fear of gaining too much muscle. Unfortunately this fear is quite unfounded. Women don't have high enough levels of testosterone to enable large muscle gains, without training at a very high level. Therefore if you are one of these women, and you want to burn fat, you're missing out on a big opportunity to lose fat without spending hours doing cardio workouts!
Just like with men, heavy resistance training can help you to burn fat. It will convert your body into a fat burning machine, by increasing the quality of your muscle. Yes, you'll gain some muscle, but you won't start to look like a bodybuilder, you'll just improve your natural shape.
Why do you want to lose fat? If it's for pure health benefits and you're not interested at all in aesthetics, then cardio will generally burn more calories per minute when you're working out. However the post exercise calorie burning effect will be much lower, so it depends if you like cardio and want the cardiovascular training benefits. If you take this to it's extreme you will develop a very lean, slim body akin to a marathon runner or long-distance cyclist due to the physical adaptions to exercise.
Sometimes people lose weight through diet alone and you can see that their body is still very soft and unshapely. This is because the muscles that were under the fat still have very little tone and therefore appear soft and small.
If your main goal for fat loss is to look more shapely, toned and lean. Then building muscle makes more sense. Muscle improves your overall body shape, increases your basal metabolic rate and gives you more strength and power. You can still train very hard, burn through fat and not look like a body builder, if you were concerned of becoming too muscular.
Another thing to bear in mind is the capacity of muscle to contain intramuscular fat. This is fat stored inside the muscle. So if you think of the muscle as a sponge and fat as water, bigger muscles are like a bigger sponge, they can soak up more fat and store it before it gets stored in less desirable places such as your belly. In other words a more muscular body has more places to spread the fat!
High-rep, short-rest exercise or repetitive exercise such as steady cardio will mainly work out the slow-twitch muscle fibres and stresses the body. This causes the release of cortisol, which suppresses the release of both testosterone and growth hormone. These two hormones are both strong fat-burners, so without them your body won't naturally burn fat as easily.
Lifting heavy weights to a maximum of 12 reps per set, with adequate recovery will do the opposite. It'll boost testosterone and growth hormone, turning you into a fat burning machine!
Of course if you're looking to really reduce your body-fat percentage then dietary improvements will yield the greatest results compared to any exercise. However, as we mentioned above, simply losing fat and not improving muscle tone and/or size will lead to less-than-desirable results (from a purely aesthetic point of view).
So to answer the big question, yes, lifting weights will burn fat. It will also give your body more natural fat-burning capacity even at rest. It'll boost your metabolism and give you a body that looks less fat, when compared to a body with less muscle but the same amount of fat tissue.
The traditional thought, that cardio is the number one way to burn fat, is over rated. You can actually burn fat quite efficiently by simply lifting heavy weights!
That is a key point, the weights need to be heavy. You shouldn't be able to perform more than 12 reps per set, otherwise you're approaching muscular endurance territory and won't reap all the benefits of weight training.
If you're looking to apply this to your everyday training and start losing fat and reshaping your body then you'll need some weights, our 50 KG cast iron dumbbell and barbell set is the ideal starter set.
1. Schuenke, M. D., Mikat, R. P., & McBride, J. M. (2002). Effect of an acute period of resistance exercise on excess post-exercise oxygen consumption: implications for body mass management. European Journal of Applied Physiology, 86(5), 411-417.