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Answered: Cardio or Weights for Fat Loss?

Avatar Nutrition Staff

September 5, 2017


The great gym divide: Weights vs. cardio.

Walk into any gym across the country and ask people what they’re training for, the almost unanimous response would be ‘to look better.’ Why then, are peoples’ approaches so polarized?

Half the folks in the gym pound away at the treadmill or the elliptical, while the other half lift dumbbells or barbells and grunt away on machines.

When you to ask each group what they were training for, it’s likely the cardio folks would answer “to lose weight” while those in the weights section would respond with “to build muscle.”

cardio or weights

To the unknowing, this makes sense.

After all, cardio burns calories (which is crucial for weight loss) and weight training breaks down and rebuilds muscle tissue, which makes you bigger.

But what does the research say? Is the common belief that cardio is better for weight loss right, or is the bodybuilding fraternity onto something, even if they don’t know why?

What Burns More Calories?

Let’s talk calorie balance.

For fat loss, you need a negative calorie balance (known as a deficit) where you’re burning more calories than you consume.

It would make sense, therefore, that the most beneficial use of your gym time is the one that burns the most calories, as it pushes you into a bigger deficit, and thus means you drop weight quicker.

When we look at calories burned per 30-minutes of exercise, the activities that come out on top are high-intensity cardio drills or sports, such as running and cycling (the faster you go, the more calories you burn), swimming, handball, water polo, rock climbing, and certain gym machines [1].

A study from the Journal of Applied Physiology compared aerobic training (AT), resistance training (RT), and the two combined (AT/RT). Their results found that in terms of body mass and fat mass, both AT and AT/RT had the greatest impact, though AT/RT required double the time commitment. They concluded that aerobic training was the optimal mode of training for weight and fat loss [2].

The trouble is, studies like this tend to be somewhat short-sighted.

“As your body gets better at doing cardio, the oxygen cost of exercise goes down so that you burn fewer calories for a given amount of work.”

Over time, the body may adapt to regular cardio sessions—and not necessarily in a way that will be helpful for fat loss. As your body gets better at doing cardio, the oxygen cost of exercise goes down so that you burn fewer calories for a given amount of work. Your body becomes more efficient. This may mean that you have to do longer and longer sessions to burn the same amount of calories you were when you first started.

Also, if you try to accelerate fat loss by choosing cardio over lifting weights, your risk of muscle loss and metabolic slowing may be greater. Metabolism and muscle play a key role in long-term fat loss success.

Muscle and Metabolism – Key Players in Fat Loss

The main thing weight training helps with is building muscle, and while that may not seem like a major concern when fat loss is your primary goal, muscle is vital for burning fat and getting leaner.

Aerobic training may help decrease body fat, but it does little to increase your basal metabolic rate (BMR) [3].

The more muscle you have, the more calories you burn. Research suggests that for every kilogram of muscle you have, you burn around 13 calories per day—and that’s just while sitting [4]! When exercising or moving around, having more muscle can mean burning hundreds more calories. This will make fat loss easier in the long-term even if you carry only a few pounds of extra muscle.

A secondary, shorter-term benefit of resistance training is the immediate rise in metabolic rate.

This is known as EPOC, or Excess Post-exercise Oxygen Consumption, and refers to the increase in calorie burn AFTER a training session as your body attempts to repair itself and replace energy stores used up in training.

Where muscle damage is minimal with cardio, the EPOC effect isn’t too great. With resistance training, however, the body has to work hard to repair and grow new tissue, and so increases its calorie expenditure to cope with this. EPOC may contribute an additional 6-15% to the calories burned during a session (5), and it seems that the higher intensity the exercise, the higher the EPOC (6).

Weight Training = A Better Physique

Let’s say for a moment that both cardio and weight training bring about the exact same amount of fat loss over the long term.

Which do you think would give you the better physique—doing just cardio, or doing just weight training?

Unless your idea of the perfect body is one that lacks definition and is prone to injury, then we can all agree that weights will probably give a better physique.

weights for toned body

Without sounding too much like a fitness magazine for middle-aged women, weight training gives your body better shape and tone. If you’re dieting down for any kind of competition or photo shoot, then we also know that resistance exercise is vastly superior for retaining lean tissue and preventing muscle loss [7].

As much as anecdotal evidence shouldn’t be the basis of any argument, there’s a saying that ‘success leaves clues.’ Enough men and women who’ve developed incredible physiques have performed weight training as their main form of exercise, so it’s safe to say that the argument of whether weights or cardio gives a better physique is pretty much decided.

How About Health?

Your mind is probably drawn to cardio when you think about what’s better for overall health and longevity, and while it’s true that cardio does have a host of cardiovascular benefits, resistance training does too. It also has many others.

Greater muscle mass is associated with lower inflammatory markers and risk of chronic disease, as well as greater bone density [8,9]. So there’s no need to automatically swap to cardio if your goal of training switches away from aesthetics and more toward being healthier and living longer.

Living in Harmony

You don’t need to choose weights or cardio.

Why not do both?

A 2008 study from the Journal of Strength and Conditioning Research noted that resistance training and cardio can support each other under the right circumstances, and should probably both be included in an effective program [10].

It all comes down to this: What are your goals?

However, if in doubt or pressed for time where you need to choose one over the other, weights should form the majority of your routine.

Plus, fat loss and a calorie deficit can be achieved by diet alone, and Avatar Nutrition can make this happen. Therefore you want your training time and efforts to go towards the type of training that will most improve your physique. i.e. weights.

Don’t take a side – it isn’t weights versus cardio; it’s about how each suits your goals.


[1] Publications H. Calories burned in 30 minutes for people of three different weights – Harvard Health. Harvard Health. 2016. Available at: https://www.health.harvard.edu/diet-and-weight-loss/calories-burned-in-30-minutes-of-leisure-and-routine-activities. Accessed November 27, 2016.
[2] Willis L, Slentz C, Bateman L et al. Effects of aerobic and/or resistance training on body mass and fat mass in overweight or obese adults. Journal of Applied Physiology. 2012;113(12):1831-1837. doi:10.1152/japplphysiol.01370.2011.
[3] Dolezal BPotteiger J. Concurrent resistance and endurance training influence basal metabolic rate in nondieting individuals. Journal of Applied Physiology. 1998;85(2):695-700.
[4] Wang Z, Ying Z, Bosy-Westphal A et al. Evaluation of specific metabolic rates of major organs and tissues: Comparison between men and women. American Journal of Human Biology. 2010;23(3):333-338. doi:10.1002/ajhb.21137.
[5] Laforgia J, Withers R, Gore C. Effects of exercise intensity and duration on the excess post-exercise oxygen consumption. Journal of Sports Sciences. 2006;24(12):1247-1264. doi:10.1080/02640410600552064.
[6] Paoli A, Moro T, Marcolin G et al. High-Intensity Interval Resistance Training (HIRT) influences resting energy expenditure and respiratory ratio in non-dieting individuals. Journal of Translational Medicine. 2012;10(1):237. doi:10.1186/1479-5876-10-237.
[7] Geliebter A, Maher M, Gerace L, Gutin B, Heymsfield S, Hashim S. Effects of strength or aerobic training on body composition, resting metabolic rate, and peak oxygen consumption in obese dieting subjects. American Journal of Clinical Nutrition. 1997;66(3):557-563.
[8] Wolfe R. The underappreciated role of muscle in health and disease. American Journal of Clinical Nutrition. 2006;84(3):575-482.
[9] Olson T, Dengel D, Leon A, Schmitz K. Changes in inflammatory biomarkers following one-year of moderate resistance training in overweight women. International Journal of Obesity. 2007;31(6):996-1003. doi:10.1038/sj.ijo.0803534.
[10] Davis W, Wood D, Andrews R, Elkind L, Davis W. Concurrent Training Enhances Athletesʼ Strength, Muscle Endurance, and Other Measures. Journal of Strength and Conditioning Research. 2008;22(5):1487-1502. doi:10.1519/jsc.0b013e3181739f08.