Cardio vs Weights - which is the most effective method to burn fat?

Many people think that if you want to lose fat, you should do more cardio, and that if you want to build muscle, you should lift weights. But it's not that simple. You can use weight training to lose fat, and in some ways it's actually better than cardio.

This topic has long been a debated issue in the health and fitness world; for decades we’ve been misled to believe that cardio training, alongside eating the low sugar/’diet’ foods that we were marketed extensively in the 70s and 80s, were the best ways to lose weight. In simple terms, to lose weight you must cut the calories and do cardio. 

 As much as it is a common misconception that you need to do cardio to lose weight, there are still multiple benefits to doing cardiovascular activity. So, let’s look at the facts.

In terms of time spent doing it, cardio training does burn the most calories. It is a fact that an hour of running will burn more calories than an hour of lifting weights. However, the least valuable thing of doing exercise is the calories you burn whilst doing it.

 When you consistently do cardio as your main method of training, your body simply gets better at doing cardio. One of the ways it gets better at cardio is that is pairs muscle down and makes you more efficient at burning calories. What do we mean by ‘more efficient’? It slows your metabolism down and multiple studies have proved this. A lot of the weight you lose through cardio training is, in fact, muscle.

 In the short-term your cardio training alongside your diet can help you lose a lot of weight. So, you’re now smaller but with a lower metabolism. But what does this look like in the long-term?

Firstly, at some point you will plateau. Then you apply the same process and lose weight again and plateau. It’s a repeated cycle, where at one point you’re eating less than before and still doing cardio until it becomes unsustainable.

The first reason I will give resistance training a point in the fat-loss war against cardio is due to the calorie burn after the workout is completed. This is because this method of training helps build muscle and increase your metabolism.

Studies have demonstrated that after a weight-training workout, metabolism can be boosted for up to 38 hours post-workout.  This means that rather than burning, say, 60 calories an hour while sitting and watching TV, you're burning 70. While you may not think that 10 extra calories is a big deal, when you multiply this by 38 hours, you can see what a huge difference it can make in your daily calorie expenditure.

When you figure that out on a monthly rate, it becomes even clearer how regular participation in weight training will really increase your capacity to burn calories, and thus fat. The effect of this training in the long-term means you should be eating more at the end of your weight loss journey to sustain your new lean body.

 With cardio training, you might get an extra 40-80 calories burned after a moderately paced session, but this will depend upon the exact intensity and duration of the workout. In order to generate a high amount of post-calorie burn from aerobics, you'd have to be doing it for a very long duration of time.

What are you telling the body by eating less calories and creating more activity/cardio training? You’re essentially teaching the body to become increasingly more efficient at how little you’re going to feed it and how much you’re asking it to do. Your body doesn’t know when you’re going to feed it next and hence why it will cling onto its fat reserves. This is why we are unable to keep the weight off in the long-term.

The second factor to consider in the fat-loss war is long-term metabolic increases. While it's great to be burning more calories for 38 hours after the workout, that's not going to help you two weeks from now, unless you are consistent with your workout program (which you should be, but that's not the point we're trying to make here).

What weight training will enable you to do is build up a larger degree of lean muscle mass, which then basically serves as a calorie-burning powerhouse in the body.

When you calculate your basal metabolic rate, which is how many calories you would burn if you stayed in bed all day and did absolutely nothing except breathe, one of the factors that goes into this is your total body weight. The most accurate equations will also take into account lean body mass, which represents your muscles, bones, and organs.

The more muscle you have on your body, the higher this rate will be and the better the calorie-burning results you will obtain 24/7.

An efficient metabolism is a good goal to strive for. We need a fast metabolism now in our Western modernised society where food (particularly highly processed food) is abundant, and our lives are becoming increasingly sedentary. Since muscle tissue is fairly stable (as long as there is some stimulus on the muscle and you are consuming enough protein, it won't be lost), this continues to be the most bullet-proof long-term strategy for losing body fat.

Speaking of our fast-paced Westernised society, we often are too time-poor to exercise. This is again where resistance training is a fitting choice for those who have little time to exercise in their week; it is a training modality that doesn’t need to be performed nearly as often as cardio. In fact, for the average person two times a week is plenty!

 To add a final point to resistance training for its health benefits, it is one of the only forms of training that positively influence the hormones. This is because the main signals to build muscle, and the hormones associated with building muscle - testosterone, better growth hormone, lower cortisol, balanced oestrogen/progesterone, etc. - start to activate. Cardio doesn’t send the same ‘preserve muscle’ signals.

It's time to break free from the thinking that cardio equates to fat loss and weight training equates to building muscle and weight gain. It's simply not as clear cut as that. While it’s generally proven that resistance training does have the longer-term benefits for your health, we cannot ignore that cardio training has a bigger influence on cardiovascular health, since your heart and lungs work harder for longer when you do it.

So, while you likely shouldn't eliminate cardio from your fat-loss training program, you should be putting forth good effort toward weight training as well. Otherwise overlooking this fine balance of both training modalities could delay your long-term fat-loss goals.