In today’s instalment of #ByronKnowsBest I want to talk about high intensity interval training (HIIT) and fat loss. Now, I appreciate fat loss is a hugely expansive topic covering many areas, so today I’ll break it down to basics and leave you with some tips on how, with HIIT, you can become a fat burning machine.
High-intensity interval training (HIIT) is an enhanced form of interval training, an exercise strategy alternating periods of short intense exercise with less-intense recovery periods. Typically my HIIT sessions vary between 5 and 25 minutes depending on the overall intensity of the session. These short, intense workouts provide greater athletic capacity and condition, more efficient glucose metabolism, and improved fat burning.
In order for me to explain why HIIT is, in my opinion, superior for fat loss over other options, I need to give you a quick science lesson on why we store excess body fat.
The Science Bit

So how does it work? It all becomes much clearer when you realise that fat loss depends almost entirely on achieving the right internal hormonal environment and very little to do with calorie restriction. And I can prove it. When people with the same diet and exercise programme go through a hormonal change in their late 40s/early 50s, they find it harder and harder to lose fat. And I’d be a rich man if I had a pound for the amount of times clients have told me they’re on a low calorie diet and they just aren’t losing any weight (or they lose a little then put it all back on again). Creating this environment is achieved in two ways. Firstly by leaning towards a diet which is permissive for fat loss (coming in the next instalment of #ByronKnowsBest) and with high intensity exercise.
Why should I choose HIIT?
This adrenaline producing, quick style of training is the polar opposite to what you see 90% of gym goers doing, and I’ll share the secret as to why it works so well.
Your muscle cells burn energy in two ways, aerobically (with oxygen) and anaerobically (without oxygen) and here’s the difference
- Aerobic exercise – Steady state treadmill walking or light resistance training
- Anaerobic exercise – Flat out sprinting or throwing a heavy weight overhead
As if that’s not enough, HIIT also causes what’s known in the fitness world as the afterburn effect. Put simply it keeps your body releasing energy and burning calories long after you’ve left the gym, opposed to the steady state alternative where you only use energy when performing the activity. It’s something to think about when you’re watching T.V after a good session!
HIIT training is also an attractive prospect to those of us with a busy schedule. It has revolutionised personal trainers, because now the - “I just haven’t got the time” excuse, just won’t wash. I mean who can’t find 5 minutes?! And within that 5 minutes you’ll get a workout which guarantees fat loss results – something you
weren't getting before. And come on, who wants to stand on a treadmill for an hour?!