HIIT has long been hailed as the “best” form of cardio for shredding body fat, but in recent years we’ve seen the emergence of a new contender…

… yes, it’s Insanity!
The boffins behind this much-hyped program (BeachBody) claim that their system can deliver better results and shorter workouts, promising to turn you into “a 24/7 fat burning machine!” thanks to an interesting technique they call MAX interval training.
They believe it blows HIIT out of the water, so today I’ll put both methods to the test and crown a champion.

The Ad To End All Ads
Before we go any further, let’s give a shout out to whomever created Insanity’s late night infomercials.
Seriously you deserve a pay rise.
These 30-minute sell-a-thons are done with such an elite level of marketing prowess that even the staunchest of sceptics would be tempted!
Trust me, if you’re sat in your underwear at 3am holding onto a king-sized chocolate bar and an overbearing sense of guilt (been there), nothing will convince you to “get back on it tomorrow” more than these oiled up machines, who explode onto your television screen claiming they can make everything okay again for three easy payments of $99.99.
However, I’m not a customer.
And in order to convince me that they’ve changed the laws of thermodynamics and discovered the “Holy Grail” of fat loss methods, BeachBody are gonna have to turn down the hype and bring the science…

Know The Differences
Many people mistakenly believe that Insanity actually is HIIT.
It’s not, though.
I can see why people would assume this, because when you’re working “flat out” they kinda look the same, but when we dig deeper there are a number of subtle differences which set them apart from each other.
Let’s take a look:
- What is HIIT?
Rising in popularity in the late 1980s, high intensity interval training involves performing short bursts of hard effort followed by a recovery phase.
This fast/slow template forces the body to burn through carbohydrates for fuel (just like weight training), and it triggers a mechanism called EPOC (a.k.a. “the afterburn effect”) which sees your body continue to burn calories at a slightly accelerated rate for up to 14 hours after your session finishes. (1, 2)
- What is Insanity?
This program is built around a training method they call MAX Interval Training.
BeachBody would like you to believe that this is a newly-discovered technique which they invented, but it’s otherwise known as HISS (high intensity steady state), and it’s been around for a few decades.
Unlike HIIT, this method has you doing significantly longer bursts of maximal intensity followed by shorter rest breaks, essentially flipping the HIIT formula the other way round.
Here’s how a 15-minute workout would look:
High Intensity Interval Training (HIIT) | MAX Interval Training (HISS) |
---|---|
30 seconds maximum intensity | 2 mins maximum intensity |
2 mins recovery | 30 seconds recovery |
30 seconds maximum intensity | 2 mins maximum intensity |
2 mins recovery | 30 seconds recovery |
30 seconds maximum intensity | 2 mins maximum intensity |
2 mins recovery | 30 seconds recovery |
30 seconds maximum intensity | 2 mins maximum intensity |
2 mins recovery | 30 seconds recovery |
30 seconds maximum intensity | 2 mins maximum intensity |
2 mins recovery | 30 seconds recovery |
30 seconds maximum intensity | 2 mins maximum intensity |
2 mins recovery | 30 seconds recovery |
15 mins total | 15 mins total |

Which One Is Better For Fat Loss?
HIIT wins, and it’s not even close.
Don’t get me wrong, though, Insanity definitely has some merits and it’s still a great fat burning program.
Heck, I used it myself during 2015-2016, so I have first-hand experience of how effective it is (even though the whole thing feels like a glossy vehicle for BeachBody’s over-priced supplements!).
But as good as it may be, there’s not defeating the mighty HIIT when it comes to burning fat and improving your fitness levels, and there’s four key reasons why:
- HIIT uses progressive overload
Anyone who has lifted weights will be familiar with the term “progressive overload”.
This is the process by which we increase the stimulus for our body to work against (e.g. increasing the size of the dumbbells you lift, or how many reps you can do) to ensure that you are always pushing your body to grow bigger and stronger.
It’s our primary muscle building pathway.
HIIT is based around this very same concept, because you can change several variables to ensure you continue pushing your body to new heights. This can include:
- Changing the length of each burst phase
- Changing the exercises to work different muscle groups
- Changing the length of recovery phases between each burst (my personal fave)
Insanity (or any other home workout program) doesn’t offer these kind of luxuries, so most people who complete it fall into the trap of just re-doing the exact same program from the start and promising themselves that they’ll “go even harder”.
- HIIT activates those all-important “Type 2B” muscle fibres
Our body has three types of muscle fibres; Type 1, Type 2A, and Type 2B.
Type 1 are mainly used for endurance-based activities, and type 2B are mainly used for explosive movements.
I’m sure we’ve all seen the old meme of the long distance runner and the sprinter, yes?
Here’s where things get really interesting, because the third type of muscle fibres (Tpe 2A) has the capacity to transform into either of the the above depending upon the workload they receive.
Now, considering most of you want to own an lean, muscular physique, it makes sense to prioritise a training method which turns those Type 2A muscle fibres into additional Type 2B muscle fibres, right?
So with that in mind, it’s worth knowing that HIIT and weight training will trigger this response to the maximum effect, whereas any form of steady state cardio exercise (even as ferocious as HIIS) will shift the focus to creating additional Type 1 muscle fibres. (4)
- HIIT is much safer
It’s no coincidence that figures show a spike in ACL injuries during the peak of Insanity’s popularity!
The combination of so many high impact explosive movements (power squats, jump lunges, burpees, etc) and the unforgiving structure of HISS can be a recipe for disaster.
Also, the fact that BeachBody openly targets newbies with their adverts for such a brutal program doesn’t help, because all it takes is one bad landing, or one awkward twist, to get side-lined for several weeks. Most of the people I’ve spoken to over the years who experienced injuries while using Insanity put it down to that, but sometimes even experienced trainees wound up getting injured as a result of trying to “out-train” their previous selves in a bid to make the program harder on the second go round (see above!).

- HIIT offers more variety
I’ve always believed that variety is the key to consistency in the gym, and HIIT is choc-full of it!
There’s no bigger progress killer than boredom, so the fact that you can apply HIIT protocols to almost anything makes it a fucking lifesaver. Considering it’s time-based and not a specific list of exercises, you could setup a HIIT workout which involved circuit training, or jump rope, or swimming, or sprinting on a running track – it’s all still HIIT!
When we get stuck with a rigid program template the novelty wears off quite fast, and before you know it you’re contemplating murdering the next guy who tells you to do a bodyweight jump squat.


References:
- Trembalay, A., et al. Impact Of Exercise Intensity On Body Fatness And Skeletal Muscle Metabolism. Metabolism (1994).
- Knab, A. M., et al. A 45 Minute Vigorous Exercise Bout Increases Metabolic Rate For 14 Hours. Med Sci Sports Exerc (2011).
- Mangine, G. T., et al. The effect of training volume and intensity on improvements in muscular strength and size in resistance-trained men. Physiol Rep (2015).
- Wilson, J. M., et al. Concurrent Training: A Meta Analysis Examining Interference Of Aerobic And Resistance Exercise. J Str Cond Res (2011).