If you want to lose fat, your first consideration should be your diet. It doesn’t matter how hard you train, if you are eating too many calories you will never create the calorie deficit necessary for fat loss. If your fat loss has stalled, make sure your diet is aligned to your goal. Otherwise, and irrespective of what type of training you do, you’ll never make much meaningful progress.
Now, with that out of the way, what about the best type of exercise for fat loss: is cardio the fat-burning champion, or is strength training the way to go?
Cardio burns calories and most of those calories come from fat. It’s also good for your heart, lungs, and circulatory system, and therefore your health too. In short, everyone should do at least some cardio every week (even if you hate it).
However, while cardio does burn calories and fat, it does it at a relatively slow rate, and only while you are actually doing it. A 30-minute cardio workout will burn around 300 calories and so, to lose a single kilo of fat, you’ll have to complete around 12 hours of cardio.
Cardio also has minimal impact on your resting metabolic rate. In other words, while you will burn more calories than normal while you are exercising, not long after you stop, your metabolic rate will return to normal. That means you not only need to do a lot of cardio to lose fat, but you also need to do it often to continue to lose weight. A missed workout means a missed opportunity to burn calories, and the more workouts you miss, the slower your weight loss will be.
Finally, it’s important to understand that it’s quite hard to burn off 300-600 calories with cardio but very easy to eat that same amount. A couple of cookies and a packet of potato chips will undo any benefit of your cardio workouts. Also remember, when a workout quotes the number of calories you’ll burn from completing it - this also adds the number of calories you would burn from doing nothing, which is the numbers always appear to be really high!
Lifting weights burn slightly fewer calories per hour than cardio, and more of those calories come from carbs rather than fat. This might suggest that cardio is the best way to shed that unwanted blubber. But, before you cancel your gym membership and take up jogging, it’s important to consider the following:
While strength training may burn fewer calories while you are exercising, it tends to increase your metabolic during the hours and even days that follow. This is because of a phenomenon called EPOC, short for Excess Post-Exercise Oxygen Consumption, and also known as ‘afterburn’.
Strength training causes the build-up of lactic acid and other exercise byproducts, and your body has to use energy getting rid of it. In short, strength training can elevate your metabolic rate for up to 48 hours after exercise. Strength training also dramatically increases insulin sensitivity, meaning carbs consumed after exercise are preferentially moved into your muscle and liver cells, and away from your fat cells.
Finally, strength training builds muscle which further increases your metabolic rate. Adding just a little muscle to your body can significantly increase the number of calories you burn per day. Remember, the majority of the calories you burn each day are not used during physical activity but by your resting metabolic rate.
SO, WHICH TO CHOOSE?
The answer is that both approaches CAN work and really it depends on which approach you prefer and enjoy. Burning fat through cardio alone means you’ll have to resign yourself to exercising for 30 minutes or more most days of the week, and that a missed workout will delay fat loss.
In contrast, lifting heavy weights means you’ll burn fewer calories per workout, but your metabolic rate will increase so you’ll continue to burn fat and calories at an accelerated rate even on the days you don’t exercise.
The best option is to do both – preferably on alternating days. Do a full-body heavy weights workout one day, and then do a cardio workout the next. If you only have a few days a week to train, simply add some HIIT cardio straight after your workout. This should give you the results you want in the shortest possible time; assuming your diet is on track of course!