Today I’m going to showcase a great video released a little while ago from a guy named Craig Ballantyne. For those of you unfamiliar with Craig’s work, Craig is a huge proponent of circuit training as the best approach for fat loss. In fact, he’s created an entire workout program called Turbulence Training that involves workouts designed for rapid fat loss.
In this video, Craig makes a great point about how futile a tool steady state cardio is for fat loss, particularly in the absence of dietary control.
This video serves as a great reminder for everyone that just because you exercise, it does not give you license to eat whatever you want. In other words, 30 minutes on the elliptical trainer is not a suitable excuse for downing a bag of cookies.
A second important lesson is that “calorie burn” during a workout is a minor contributor to the weight loss equation! What is far more important is the amount of metabolic change your exercise bout induces in the 24-48 hours that follow each exercise session. No one finishes a resistance training workout and brags that they’ve just build 1/36th of a lbs of muscle… yet everyone proudly recites how many calories their workout burned. I don’t get it.
Regardless, to help us see how trivial calories burned during a workout truly are, I’m going to enlist the help of my friend Becky Macpherson, who recently completed a brilliant study comparing sprint interval training to steady state cardio.
For her 6 week training protocol, she recruited young (average age: 23 years), recreationally active individuals (average body fat: 19.6%) and had them perform either:
Steady-state endurance training
- 3x/week
- run at 65% of VO2 max (moderate intensity running)
- 2 weeks at 30 minutes, 2 weeks at 45 minutes, 2 weeks at 60 minutes
- Total exercise time: 13 ½ hours
Sprint interval training
- 3x/week
- 30 second max effort sprints, followed by 4 minutes rest
- 2 weeks at 4 sprints, 2 weeks at 5 sprints, 2 weeks at 6 sprints
- Total exercise time: 45 minutes (with 6 hours of rest)
Even a quick look at these numbers reveals a staggering difference in total workout volume. Although calorie expenditure during the bouts wasn’t directly measured, we can estimate some numbers.
If we take a hypothetical 70 kg individual, they might burn ~24 kcal/min of sprinting. Therefore, in 45 minutes of sprinting they would expend a little over 1000 kcal (~1080 kcal) in the 6 weeks of training.
Conversely, in the group that did the endurance training, a 70 kg individual who ran at 6 mph (this is a low estimate), would burn ~12 kcal/min. Therefore, over the 13 ½ hours of training, they would burn close to 10,000 kcal (~9720 kcal).
Keep in mind, these are rough estimates but it’s fair to say that the endurance training group burned about 10x as many calories through exercise over the 6 weeks than did the sprint interval group.
So obviously we’d expect the group that burned 10x as many calories to lose more weight, only that’s not at all what happened. Take a look for yourselves:
Machperson et al. (in press)1.
What we see is that after 6 weeks of training, the sprint interval group loses 1.7 kg of fat on average whereas the steady state cardio group loses 0.8 kg of fat on average. In other words, sprint interval training was 2x more effective for fat loss than steady state cardio, despite the steady state group training 18x as long!
This my friends, is the kind of science you need to pay attention to. It’s not some hypothetical projection based on the results from a test tube or a rodent. No, this is meaningful training data done over 6 weeks in humans.
So the next time you are lying on the gym floor following an intense bout of incline treadmill sprints, if your friend saunters over after their 60 minute elliptical workout and brags that they just burned “527 calories today”, try to resist the urge to snicker at their saddlebags and instead educate them on the benefits of training intensely.
It’s a challenge to erase misguided beliefs, but when we embrace good science, at least we have some hope.
Till next time, train hard and eat clean!
1. MacPherson REK, Hazell TJ, Olver TD, Paterson DH, & Lemon PWR. (2010). Run sprint interval training improves aerobic performance but not max cardiac output. Medicine and Science in Sports and Exercise. In Press
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