Slow Up to Slim Down? Sounds Good, But Don’t Believe It.
“Hey, hey, hey. Take it easy out there.”
That’s the secret. The panacea. The Magic Bullet. Pedal long, pedal gently and you’ll fry the fat faster. The alleged Big Bonus of Base Miles: Keep your intensity in the “fat-burning zone”, or FBZ——no more than 65% to 70% of your max HR and the fat fairly flies off you. Crank up the intensity higher, and your working muscles draw more glycogen (which comes from carbs) than fat for energy.
No pain GUARANTEES no gain.
An enticing pitch, but don’t fall for it, Dr. Lynn Goldberg of the OHSU Human Performance Lab once warned me. “Senseless” was his take on the notion that less strenuous exercise taps into the fat bank for fuel, thus trimming you more quickly, whereas more intense workouts withdraw carbs, leaving your fat stores still on deposit in your thighs and handles, and on your ass.
You can use up MORE calories, and burn JUST AS MUCH FAT, by working out at higher-than-FBZ intensities. Now, it IS true that when you are riding at FBZ, your body does draw on fat for a sizable chunk of its energy needs.
See, body fuel comes in 2 octanes: fat wrapped around organs and layered under the skin, and carbo-derived glycogen stored in the muscles and liver. Which energy source your body chooses depends on how much energy it needs. And how quickly.
Pedal at higher HR, and your body uses mainly carb fuel, because it’s already in the muscles, ready to burn. AND unlike fat, glycogen can be converted into energy without oxygen - a commodity in short supply when your HR is bouncing off the roof of your target zone, and you’re sucking in air through your eye sockets.
But reduce the exertion level, as in gentle pedaling at, say, 15-16 mph, and your body switches over to fat as its fuel de jour. This part is true. You WILL burn a higher RATIO of fat during extended low intensity miles than you will at an effort hard enough to make you pant.
About Carlo Delumpa
When Carlo is not on his bike, he is usually thinking about his bike - or biking, bike accessories, this web site and the cute chick that shares his tandem. Carlo is a native of the SF Bay Area, where the weather is warm and the climbs go on forever. He's slowly winning the NW rain game with other sports, like skiing and hockey. And the climbing in Portland can go on forever if you don't mind going downhill a few times in the opposite direction.
Carlo is a co-founder and director of this illustrious cycling club, and the lead designer of pretty much anything Velo you see out there (with the possible exception of the race team swag). It lets him get out his creative yah-yah's and now that he's got a new iMac, watch out - you may see Portland Velo logo tattoos in the not-so-distant future.
Ever-so-approachable, Carlo is always open to ideas, suggestions and even criticism if it means making this an even better community. You can reach him at carlo@portlandvelo.net. Please keep the criticism limited to 25 characters or less, please.