Will Hiit shed your fat faster?
Hiit training (High Intensity Interval Training) strategies have gotten a lot of good press over the last few decades, and in this article we’re going to investigate the claim that they’re a superior exercise for weight loss.
Dr. Izumi Tabata’s 1996 study1, showed that alternating between intervals where we work out at close to our maximum aerobic capacity with rest periods lets you become fitter more rapidly than if you just did continuous moderate exercise.
Since then, Crossfit gyms and plenty of general fitness junkies have added this method to their workouts, at least periodically.
But over that time, something interesting has happened. The idea has taken hold that HIIT also burns more fat than endurance exercise, even though HIIT training almost always takes place across a shorter period of time than your standard endurance workout, and burns fewer calories. Some even claim that endurance exercises like biking and running makes you fat.
A recent meta analysis drew on 28 studies comparing steady state cardio to various types of HIIT training for body fat reduction. In all, 837 men and women were involved in these studies.
The authors actually looked at two different types of interval training. The first was Sprint interval training (SIT), which they defined as an “all out” (greater than 100% of V02max) effort lasting eight to 30 seconds mixed in with recovery periods. The second was high intensity interval training (HIIT), which they defined as submaximal (80-100% of VO2max) intervals of exercise lasting 60-240 seconds mixed with with less intense recovery periods.
They compared these two types of intervals with moderate-intensity continuous training (MICT), which they defined as steady-state cardio work lasting 20-60 minutes at a moderate intensity of 40-59% of VO2max.
The studies this meta analysis drew on mostly looked at stationary bicycling and running, since these could be done in both steady state, HIIT, and SIT format.
HIIT Vs Endurance Cardio
It shouldn’t shock anyone to find out that despite diligently working out for an average of 12 weeks, participants, on average, lost very little fat, regardless of the type of exercise done.
HIIT and SIT trainers lost an average of only 1.26% of their body fat, while MICT lost an only slightly higher 1.48% of their body fat. There was no significant difference between HIIT and SIT styles of interval training.
People regularly sign up for gym memberships when they want to shed pounds, but this meta analysis, and dozens of previous studies on various exercise-based weight loss trials, have found that it’s not an effective strategy.
Exercising without making dietary changes or putting limits on caloric consumption causes an increase in appetite and other compensatory mechanisms, which negates much of the weight loss being caused by the exercise. 2
There’s actually not even an association between the amount of physical exercise done and the body fat mass of children 3.
On the other hand, when you bring diet into the picture and combine it with exercise, results are better. 4.
But the biggest role exercise has to play in weight loss may be the maintenance of your new lower bodyweight once you’ve shed some pounds. 5. Those who regularly exercise are far less likely to regain weight than those who don’t.
Hiit vs Endurance Cardio: Summing Up
- Steady state cardio was more effective than interval training for fat loss, but only because it burns more total calories.
- The intensity of workout intervals had almost no bearing on the amount of fat lost.
- Interval training, despite underperforming, was still relatively effective, and may be the better choice for those who hate steady state cardio or who have limited time to exercise.
- All things considered, none of these exercise modalities lead to large amounts of weight loss, so relying on exercise to be the driver of your fat loss is questionable.
Only a minority of people can lose lots of weight through exercise without dietary change. I suggest that my coaching clients should focus on doing exercise for muscle gain and maintenance, general health, and with regard to how it affects other areas of life.
If your chosen exercise modality causes a big increase in your appetite, or causes you to move your body dramatically less when not exercising, it’s probably not ideal. It also has to be enjoyable enough that you can stick to it for the long term.
If you want to lose weight, check out my book, Raw Food Weight Loss And Vitality.
Rosenkilde, M. Et al. Body fat loss and compensatory mechanisms in response to different doses of aerobic exercise–a randomized controlled trial in overweight sedentary males. Am J Physiol Regul Integr Comp Physiol. 2012 Sep 15;303(6). Link.↩