We may have known for some time that cardio isn’t essential for fat loss, but that doesn’t mean it can’t help … A lot.
Losing body fat comes down to one thing and one thing only: Being in a calorie deficit. I.e. You need to be burning more calories than you’re eating. While it’s perfectly possible to achieve this through diet and weight training, or even just diet alone, most people are going to benefit from doing some form of cardio, as this increases their calorie burn, raises their deficit, and should help them lose fat faster.
But that begs the question - What’s the best cardio for fat loss?
Types of Cardio
You could potentially break down cardio into more than half a dozen different categories, but for the purposes of this article, we’ll use 3 main forms of cardio -
- HIIT (High-Intensity Interval Training)
- LISS (Low-Intensity Steady State)
- NEAT (Non-Exercise Activity Thermogenesis)
20 years ago, HIIT style training was solely the domain of athletes, and perhaps the odd circuits class. It was rare that anyone involved in bodybuilding or physique sports would even consider any type of interval training, for fear of losing muscle mass.
The jury still seems to be out on this.
On the one hand, it makes sense to assume that, if you’re going all-out in your cardio sessions, your body may not be able to recover fully before you next lift weights, and therefore, lifting performance can be compromised.
Likewise, where almost all forms of cardio are heavily leg-dominant, if you’re not used to HIIT, then the DOMS from your first half a dozen sessions will mean your lower-body workouts are negatively impacted.
On the flipside, HIIT has been shown to potentially increase testosterone levels slightly over lower-intensity cardio, (1) as well as lower insulin resistance, and improve glucose tolerance and fat oxidation. (2)
The one area where HIIT does seem to stand out is from a fitness perspective. A 2018 study from the Open Access Journal of Sports Medicine found that interval-based training appeared superior to steady state-style training when it came to improving cardiorespiratory fitness. (3)
When it comes to time efficiency, there’s also no doubt that HIIT has the advantage here as well. It’s much easier to burn the same number of calories in less time, (or more calories in the same time,) when you’re incorporating stints of all-out effort in your cardio.
The biggest benefit LISS has going for it is that it takes very little energy to recover from.
If you’ve not done any cardio for a while, and suddenly decide to go on a 40-minute run, or sit on a stationary bike for an hour, you’ll probably have some soreness, but not nearly as much as had you done intervals for the same amount of time.
Secondly, there’s hardly any thought power involved with LISS. It’s very easy to do while listening to a podcast, watching TV, or even checking you emails. Provided your heart rate stays at around 60-70% of your maximum, (your maximum being 220 minus your age,) you’re going to be just fine, without putting too much thought into it.
Studies seem to show that when calorie burn is matched, LISS performs just as well as HIIT from a weight loss perspective. (4)
It’s crazy how often NEAT is disregarded as a form of cardio. The reason for this tends to be because we don’t even think about NEAT as being exercise.
NEAT actually has the power to contribute a very high percentage of your total daily calorie burn though. It’s basically all the calories you burn from the daily activities you don’t even think about - walking to the office, typing on a keyboard, fidgeting, doing basic chores, and so on.
While these activities may seem insignificant, the research shows that calories burned from NEAT can vary in individuals by up to 2,000 per day. (5) That means someone who has a sedentary job, commutes to work by car, and doesn’t do much around the house could be burning 2,000 fewer calories per day than a more active individual who has a job where they move or stand, commutes to work on foot (or by bike,) and typically leads a more active lifestyle.
When you break it down, 2,000 calories extra per day is 14,000 extra per week, or enough to lose an extra 4 pounds. A lot of calories burned from NEAT will be subconscious, but that doesn’t mean we can’t make an active effort to increase it, simply by being more active.
The biggest advantage NEAT has over HIIT and LISS is that there’s zero recovery involved. Even someone who’s incredibly unfit or undertrained can cope with an increase in NEAT without feeling sore or compromising gym performance.
So … What’s Best?
It would be great to give a comprehensive answer and name one single type of cardio as the absolute best.
Unfortunately, we can’t do that, because there isn’t one. What’s ‘best’ will come down to a number of factors.
If you’re incredibly pushed for time, it’s likely HIIT will be your best choice, simply due to the fact you’ll get a higher calorie burn in less time.
If you’re got a little more time, and prefer to do cardio at a more leisurely pace, while browsing your phone or catching up on some TV, your fat loss results aren’t going to suffer from making your primary cardio LISS.
And, if you don’t want to spend any more time in the gym, or feel there are simple ways you can increase your NEAT, either by getting a standing desk, walking part of your journey to work, doing some gardening/ yard work at the weekends instead of sitting down and watching TV, then go for that.
The bottom line is it’s all about calories. 500 calories burned from LISS is the same as 500 calories burned from HIIT, is the same as 500 calories burned from NEAT.
The harder you work, the more calories you burn. But the harder you work, the more chance there is of your lifting performance suffering.
So do what works for you, and just remember - No matter how much cardio you do, your diet should still be the main driver for creating a calorie deficit, and, if you want to maintain muscle, lifting weights should still be your primary form of training.
Cardio is very useful for increasing calorie burn and improving fitness, but it won’t change your physique on its own.