It's a common question many trying to lose weight ask: is HIIT or incline walking better for weight loss? On one hand, HIIT (short for high-intensity interval training) has long been touted as a sure-fire way to carve fat, whilst a brisk walk has also been said to do the same. So which one is better for you? This article will outline the benefits and shortfalls of both, so you can make the best decision inline with your fat loss goals and the stage of your weight loss journey.

HIIT vs LISS for fat loss: How many calories burned?

what's better weight loss

For those of you who aren't aware, HIIT is periods of all-out intensity followed byperiods of rest. You might do 60 seconds flat out on the rower, and then rest for 30 seconds, and repeat this for 20-30 minutes. You can do it in the park with sprints, or swimming.

This is in comparison to going for a 45-minute incline walk on the treadmill at a brisk pace, which is referred to as LISS; the abbreviation for low-intensity steady-state cardio.

The treadmill walk might burn about 200 calories, and the HIIT might burn 300 plus. And how many calories you burn depends not only on workout duration but on how hard you're willing to push it during your HIIT session.

Tell me if this sounds familiar: people at your gym who have been turning up for years with NO changes to their body. They're not willing to suffer: they DON'T push themselves to the limit on the bench press, and when it comes to cardio, they're walking on the treadmill scrolling through Instagram. And if you asked them to do HIIT on the rower, they would give about 50% of their maximum effort. Yep, we all know them, because that's what the majority of gyms (sadly) are made up of!

HIIT is only effective if you're willing to push yourself as hard as possible in the periods you need to exercise. If you like the idea it takes "only 20 minutes" and don't push it, then you'll get absolutely nowhere. You're better off on Instagram and on the treadmill! But if you have a killer attitude when it comes to weight loss, then HIIT will save you time and help you burn more calories.

Moreover, HIIT may help blunt your appetite more (1), which is a powerful ally when it comes to not overeating. But it's something you'll have to try for yourself: test out a walk and a HIIT session of ALL OUT intensity and record your feelings of hunger on a scale of 1-10 about 4 hours afterward. Be sure to do this hunger test at the same time of the week for accuracy.

HIIT vs LISS for muscle growth

what's better for weight loss

It should also be noted that HIIT can actually help us build muscle (2), which is important for you regardless of gender when it comes to looking your best. LISS elicits muscle growth in the elderly population (70+) but not as much in subjects in their 20s (5).

If you've missed some leg sessions in the gym due to a crazy schedule, some HIIT can give you the best of both worlds as you try to build muscle mass and also lose fat. (Note: you can't gain muscle in a calorie deficit unless you're new to training, but HIIT will still help you maintain the muscle you have when in a calorie deficit and when fat loss is the goal).

HIIT can make you burn out and quit

HIIT is NOT the best option for you when you're eating very low calories, or have significantly reduced carbohydrates in your diet for a periodic ultra-aggressive approach.

This leads to burnout and hunger which can lead to overeating. So what you're eating by way of calories determines the sort of training you can do. Or, if you know you definitely want to do HIIT, then your carbohydrate intake will have to be adjusted accordingly.

But try and do HIIT frequently (4-5 sessions a week) and have a diet very low in calories and carbs, and you're in for all sorts of trouble.

You're best to do no more than 3-4 sessions of HIIT per week, as recovering from it is particularly difficult. As you get further along in your diet, LISS becomes more effective in helping you to keep losing body fat without being too taxing on your body.

VO2 Max ad Aerobic Performance: HIIT makes you fitter than LISS

HIIT for weight loss

If being fit is also a goal then HIIT is far superior; one study found that 2 weeksof HIIT training achieved a level of VO2 max that LISS needed 6-8 weeks to match (3). HIIT is simply a very practical approach to improving aerobic capacity and performance (4).

So when it comes down to it -- one is not any better than the other; It really comes down to your goal and where you are at with your diet.

Sure, 20 mins of LISS and 20 mins of HIIT means you'll burn more calories with the latter approach, but there's more to fat loss than simply burning more calories within a 20 minute period.

If you're just starting out, and you really want to do HIIT, then start with 3-4 sessions per week and taper off to 1 session a week as you reduce your calories. If/when you're at the final stages of your diet and are looking for the last bit of fat loss, HIIT will be too demanding on your central nervous system and will be too much to try and recover from. That's when LISS is advisable.

But one thing is for sure: 4-5 sessions of HIIT as you reduce calories week to week is a disaster waiting to happen. LISS must be implemented more as the period of time spent in a calorie deficit increases.

It boils down to this:

"I love HIIT and want to do it!" Ok, 3-4 sessions a week for the first ~4 weeks of your diet is ideal. Make sure your nutritionist is factoring in additional carbohydrates for energy and recovery. Drop it down to 1 HIIT session per week after 4 weeks, and then introduce LISS.

"I HATE HIIT" Then don't do it! Bring in LISS after about 3-4 weeks of dieting to encourage more fat loss.

These are simply rough estimates and are not absolutes. You know your body, and if you have a coach or a PT, so do they.

The bottom line is one cardio approach may not be significantly better than the other if your macronutrients are set adequately -- but HIIT is far more time-efficient for those who are prepared to suffer.

Now you know about which cardio option is preferable for at what stage of your diet; all the best torching that fat! 

References

(1) Trapp, E., Chisholm, D., Freund, J. et al. The effects of high-intensity intermittent exercise training on fat loss and fasting insulin levels of young women. Int J Obes 32, 684–691 (2008). https://doi.org/10.1038/sj.ijo.0803781

(2) Blue MNM, Smith-Ryan AE, Trexler ET, Hirsch KR. The effects of high intensity interval training on muscle size and quality in overweight and obese adults. J Sci Med Sport. 2018 Feb;21(2):207-212. doi: 10.1016/j.jsams.2017.06.001. Epub 2017 Jun 8. PMID: 28647284; PMCID: PMC7104622.

(3) Gibala MJ, Little JP, van Essen M, Wilkin GP, Burgomaster KA, Safdar A, Raha S, Tarnopolsky MA. Short-term sprint interval versus traditional endurance training: similar initial adaptations in human skeletal muscle and exercise performance. J Physiol. 2006 Sep 15;575(Pt 3):901-11. doi: 10.1113/jphysiol.2006.112094. Epub 2006 Jul 6. PMID: 16825308; PMCID: PMC1995688.

(4) Dunham C, Harms CA. Effects of high-intensity interval training on pulmonary function. Eur J Appl Physiol. 2012 Aug;112(8):3061-8. doi: 10.1007/s00421-011-2285-5. Epub 2011 Dec 23. PMID: 22194005.

(5) Konopka AR, Harber MP. Skeletal muscle hypertrophy after aerobic exercise training. Exerc Sport Sci Rev. 2014;42(2):53-61. doi:10.1249/JES.0000000000000007