Ask Rocco: Which Activity Burns More Calories?

Question: I've had a constant debate with a girlfriend for months over a couple fitness questions, so I'm hoping you can settle this once and for all:

1. Which burns more calories – jogging at a constant speed or doing intervals (walk, jog fast, walk, jog fast, walk)?
2. Which burns more calories – doing cardio before or after lifting weights?

Thanks in advance for your thoughtful, yet sarcastic insight! I'm looking forward to it.

– Kimberly, Cincinnati

Answer: Sarcastic, huh?! Insightful, yes, but sarcastic, never! Come on, is it really a debate, or is it a bet that you want me to settle? If it’s a bet, then I want half of the winnings. Go on, call me greedy. If you don’t like it, then call “Body by Jake.” He may even have something insightful to say besides “abbadabbas.”

To answer your question and settle the debate once and for all, an individual will burn more fat calories performing an interval-style aerobic workout, i.e. walk two minutes, run two minutes, walk two minutes, rinse and repeat, than they would with sustained speed training. The reason for this is that the body becomes very efficient at utilizing energy during sustained training. However, when interval training is introduced, the body doesn’t know what the hell to do, so it keeps burning fat. That’s the simple explanation.

To answer your second question – wait a minute – how lucky are you guys? You're getting two questions answered for the price of one. OK, back to business, now; I’ve been saying this for years and I hope it finally sinks in. First, you need to do a little warm-up, nothing too crazy, just 6-8 minutes on the treadmill, elliptical trainer, bike, whatever. Then, perform a strength training workout. After that, you should finish up with aerobic training. The workout is much more efficient this way. To illustrate my point; let's say you begin your workout with 30 minutes of aerobic training before you do your strength training. Now, you’ve just wasted about 15 minutes, because during your first 13-17 minutes all you’re burning is glycogen, which is the fuel the supplies your muscles. It’s only around minute 18 that you even start to burn fat; but by now, you’ve already depleted much of the glycogen stores that you’ll need for your weight workout. Clearly, this is not a very good use of your time in the gym.