HIIT vs LISS, which is superior for fat loss


When it comes to cardio, the 2 main forms you’re going to see are HIIT and LISS style cardio. They’re 2 very effective and easy to do methods to utilise when doing your cardio. But what is HIIT and what does LISS stand for? HIIT is an acronym for high intensity interval training. It’s a short, very high paced sprint, followed by low a low intensity phase. When I say sprint, it doesn’t mean all HIIT has to be done while running, although it is a method you can do. By sprint, I simply mean a quick, short burst where you basically do what you’re doing, as fast as possible. An example of HIIT would be on a spinning bike. Set the intensity knob high enough so your feet don’t go flying. Do 15-second high intensity interval, as fast as you can, followed by 45 seconds at a much lower intensity, done for 8 minutes. It doesn’t have to be 8 minutes, that’s just an example. LISS stands for low intensity steady state. An example of LISS would be walking on a treadmill or outside even, at a slow enough pace, without any high intensity bursts. In this article, we’re going to be going over both and find out which, if there is one, that is superior in terms of fat loss and which you should be doing.

For a while to begin with, LISS was considered the best method to do purely because it uses more fat for fuel, which is true. When I say fat, I mean fat the

macronutrient, not actual bodyfat. The calories being burned are the calories from the fat macronutrient. High intensity training tends to use more carbohydrates than fat for fuel. However, if you’ve read my article on fasted cardio, you’ll know that, for fat loss, it doesn’t actually matter whether you’re burning calories from fat or burning calories from carbohydrates. The only thing that matters is our energy balance, calories in vs calories out. This is the prime factor to take into consideration when trying to drop bodyfat. At the end of the day, protein, carbohydrates and fats are where we get are calories. A calorie is a calorie, and no matter which substrate it comes from, as long as we’re exerting more energy, so burning more calories, than we ingest, we’re going to drop bodyfat.

Because of this, opinions started to shift from LISS being superior, to HIIT. The logic behind this switch was, though not as much fat is being used during, more fat is being burned after. This is known as EPOC, or post exercise oxygen consumption. Basically, what this logic suggests is, after you’ve completed a HIIT session, you’ll burn more fat following the session, due to a higher oxygen consumption level. EPOC is most certainly a thing, however, the issue I have is peoples attitude towards it. The general public who are aware of EPOC generally tend to overestimate its ability. A study done in 2006 showed that when people performed cardio at 70% of their VO2 max for 80 mins, the EPOC effect lasted for 7 hours after. This sounds amazing, The EPOC lasted for 7 hours, that’s 7 whole hours that my oxygen level are higher than usual, I’ve definitely just burned so many extra calories… Not exactly. The EPOC only led

to a further 80 extra calories burned. I’m going to take a swing in the dark and say most people don’t perform cardio at 70% of their VO2 max for 80 minutes. Even if your half that, that’s still 40 minutes, quite a stretch, that’s only an extra 40 calories burned. Doesn’t seem all that worth it for what you get in return! Long story short, EPOC isn’t likely to account for any noticeable fat loss potential. A 30-minute HIIT session and 30-minute steady state session have been shown to burn similar calories. Interval work alternates between very high and very low caloric expenditures so the average expenditure ends up being quite the same. Even with the additional calories burned post HIIT session via EPOC, there’s a similar caloric expenditure from both modalities.

From this, you can conclude that both HIIT and LISS are similar when being used as a method of putting you into a further deficit. So, which one should you do? Like most things, it really comes down to your own preference. HIIT is extremely time efficient, you get a lot done in a shorter amount of time. As well as that, you’re generally going to work harder in a HIIT session that you would a LISS session. On the opposite side, LISS does take quite a longer amount of time and some people do find it quite boring. In terms of enjoyability and time efficiency, HIIT wins 10/10. However, HIIT does take longer to recover from when compared to LISS. I could do a LISS session every

day and be recovered to complete the next session the following day. You wouldn’t be able to do this with HIIT, where you’d be able to do 3, maybe 4 a week.

It all comes down to what you like. If you like doing some extra hard work after/ before a workout, HIIT is a good option. If you’ve the time and feel a bit fatigued post workout and don’t think you could physically do a HIIT session, LISS is always an option.

Personally, I do not think the goal of exercise, be it cardio or weight training,

should be fat loss. HIIT isn’t something you just do. It takes seriously hard work,

and if your goal is only fat loss, chances are you aren’t maximising your HIIT,

and have lost the “high intensity” aspect of it, turning it into kind of a “MISS”

moderate intensity interval training. I always say, make your training

performance oriented. Don’t go into a workout thinking, “What can I do to

burn more calories?” Going in with the mindset of putting your absolute all

into every set, rep and minute of cardio is going to stand to you much more

than exercising purely for fat loss. Think of it in this sense. I’m doing an upper

body session followed by HIIT on the bike. If I go into this session with fat loss as

the goal, chances are the focus isn’t on performing the movements correctly

and as efficiently as possible, you’re more going and doing these exercises

just to get them done because “doing stuff burns calories”. If we went into

this workout with the aim of owning every inch of every rep of every set and

actually using our muscles as best we can, followed by genuine high intensity

in your cardio, even if you aren’t focusing on calories, the quality of work

done is going to be so much better than when you were “fat loss focused”

and you actually, without realising it, burn more calories!

To conclude, HIIT and LISS are pretty much equal in terms of fat loss. If you were to choose one to do, pick which one you would genuinely prefer to do and which one you can fit into your schedule. When performing cardio, or any other form of exercise, the focus should never be “I’m doing this to burn calories!” The main focus should be performance, how you carry out certain movements and doing it as well as you can. The higher quality work done, the more your muscles do their job. You’re going to indirectly be burning more calories, without it being the main focus. As well as that, you’re reaping the many benefits that come with performing any movement as best you can!


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