Monday 14 August 2017

HIIT vs Steady State Cardio for Fat Loss

Fat loss is about nutrition. However, a good exercise program can accelerate your results. Traditionally, many people have looked to steady-state cardio to melt off unwanted fat. However, over the last almost 20 years, high-intensity interval training or HIIT has continued to grow in popularity. This brings us the important question – if you want to lose fat, which is better – steady state or HIIT? The latest research may surprise you.

This month (Aug 2017), Obesity Reviews published a systematic review and meta-analysis comparing interval training to traditional cardio for fat loss. If you are not familiar with it, a meta-analysis is a study where they study a group of studies that fit specific criteria.

Study Reference:
Keating, S. E., Johnson, N. A., Miekle, G. I., & Commbes, J. S. (2017). A systematic review and meta-analysis of interval training versus moderate-intensity continuous training on body adiposity. Obesity Reviews, 18, 943-964. Retrieved August 11, 2017.

The Methods
The researchers collected training studies that directly compared HIIT (high-intensity interval training) or SIT (sprint interval training) to moderate-intensity continuous training (i.e. traditional cardio) for changes in body fat. Each study had to last a minimum of 4 weeks. They did within-group and between-group comparisons for body composition (i.e. % body fat) and fat mass. In the end, this study included 31 studies.

There were no differences in body fat between the HIIT/SIT groups and the traditional cardio groups. When the HIIT/SIT groups used shorter times and/or calorie expenditures, traditional cardio (for longer times and/or greater calories expenditures) may actually be better. Neither group produced “… clinically meaningful reductions in body fat.”

I like meta-analysis research as it is a time-efficient way to gain important understanding of a topic

I liked that they only included training studies. If you are a trainer or someone into fitness, you should care about these studies. Too many studies these days take the quick and easy route. For example, they take someone’s blood, put him/her on the bike, and then re-take blood work. This can help scientists understand what is going on inside the body, but what we care about is what works in the real world.

Without nutrition intervention, it is no surprise that there wasn’t really much fat loss in either group. Fat loss is about nutrition, not training. It would have been interesting to compare training methods with groups that are both on a solid fat loss-eating plan.

Not all body composition methods are the same. There can be large ranges of inaccuracy – especially with certain methods such as bioelectrical impedance. Would results have been different if all the studies used DEXA (the gold standard) to measure body composition?

Many studies use untrained beginners. HIIT and sprints are more effective (and safer) for strong individuals.

Real World Application for You and Your Body Composition 
As a trainer, I hate to admit it, but fat loss is really about nutrition. This study continues to support this ugly truth. Focus on your nutrition first. Get in a calorie deficit and work on optimal protein intake. For this, I like Brad Schoenfeld's advice: 1g per pound of ideal body weight.

If someone is strong and skilled in the weight room, weight training is amazing for fat loss. In past, I think we over-emphasized weight training’s ability to increase EPOC, secrete growth hormone and raise your metabolism. These factors do not seem to be as significant as we once thought. However, weight training builds shape and tone in your muscles. It also helps make sure you are losing fat and not muscle (your body cannot afford to lose muscle if it has to survive weight training). The cool thing about weight training is that the better you get at it, the more calories you burn - you become more fuel inefficient. It is the opposite with cardio.

Out of shape beginners can start with gentle aerobic exercise to build an aerobic base (don’t get carried away with this)

HIIT is safer and more effective when you are stronger. Get stronger!

HIIT is more time-efficient – if you only have a short amount time to train – go hard!

HIIT is great for improving VO2max (how you measure someone’s aerobic fitness level)

HIIT is great for team sport athletes

Carefully select modes of cardio. Sprinting up a hill is harder and safer than sprinting on flat ground. Pushing/pulling a sled is brutally hard yet quite gentle on the joints. Sprinting on a motorized treadmill is not worth the risk. See this short video to fully appreciate the risks of treadmills.

Because HIIT is high-intensity, you cannot do it all the time. 2-4 times per week works well for most folks.

Low-intensity cardio (if not over-done) is great for recovery. It will also burn a few extra calories. If you have the time, spread these out between bouts of HIIT. Consider low-impact options such as brisk walking, hiking, swimming or cycling.

As always, I welcome your comments or questions below.

Want more on exercise for fat loss? Check out:

Athletic Training for Fat Loss

6 Program Design Tips for Faster Fat Loss

6 More Program Design Tips for Faster Fat Loss

What is the Best Type of Cardio for You?

Cardio Beats Weights for Weight Loss?

7 Habits of Highly Lean People

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