Bottom Line: Running Will Definitely Burn Fat, but Only If You Do It This Way

With all the (admittedly well-deserved) hullabaloo around high-intensity interval training (HIIT), sometimes classic cardio training, like jogging, walking, or cycling, gets left by the wayside — especially when it comes to burning fat. It's smart to balance these two activities throughout your workout routine, both for weight loss and injury prevention, but if your goal is eliminating fat, you shouldn't look at cardio, and specifically running, as a waste of time. It can play an important role in your weight-loss journey, although it's definitely not everything.

Switching Up Intensity and Exertion Burns the Most Fat

To make a long answer short: running definitely burns fat, and it's highly dependent on your fitness level and the intensity of the run. "A lot of people will get into running and they will actually lose fat and lose weight," said Dr. Steven Mayer, MD, sports medicine specialist at the Northwestern Medicine Running Clinic. "Usually, though, that will taper off over time, because the body resets its metabolic rate based on how much you're running and what you're doing." Essentially, you'll hit a plateau; your body gets used to running a certain distance, speed, or terrain, and adjusts itself, so you won't get the same fat burn benefits. One of POPSUGAR's own editors has struggled with this.

The best way to beat that frustrating roadblock, Dr. Mayer said, is to up the intensity of your runs. That could mean adding hills, increasing your speed or rate of perceived exertion, or even doing some HIIT runs with high-speed intervals and rest periods (like this treadmill interval workout). Anything that shifts up the intensity will help you burn more energy and more fat.

One caveat: if you're running for long periods of time at a high speed or rate of exertion, said sports physiologist Richard Lampman from the University of Michigan, your body might switch over from burning fat to breaking down muscle in order to give you energy. That's definitely something you want to avoid, Dr. Mayer agreed — and you can. If you're running for over an hour, he advised having a carbohydrate-rich snack, like an energy chew or gel, so you're not burning up your body's other resources.

Can Walking or Slow Jogging Burn Fat?

If you're a beginner, walking is a great way to get started with weight loss, Lampman said. He recommended walking for a set period of time, like 20 minutes, taking a rest, then walking again. (Try this week-long walking interval plan for starters.) "You can go longer that way than you could just doing it all at once," he said. If that feels too easy, start with a light jog and take walking breaks as rest. Try to increase the duration a little more each time until you don't need the breaks at all.

Dr. Mayer stressed that working out at a low intensity, like walking or a slow jog, will be an effective fat-burning workout for beginners. Once you start to get fitter, though, and the speed starts to feel easier, you'll need to increase the intensity in some way, through speed, higher exertion, or by adding in terrain elements like hills. "I have found that you really need to work with higher-intensity type of stuff to really continue that fat burn over time," he said.

Is Running Good For Burning Fat?

"I do think running is a great exercise for people who want to burn fat and lose weight," Dr. Mayer said, "but I think in isolation, it's not going to be the long-term answer." The key, he said, is mixing it in with HIIT, weight training, and core work. Weight training helps you build muscle, he said, which boosts your metabolism and helps you burn calories more throughout the day. That combination, along with interval running (and a healthy diet), is a good recipe for fat loss.