Fasting, Aerobics, and Weight Loss

GoreTex Experiance Tour - Dave MacLeod goes for a run! from Hot Aches Productions on Vimeo.

I just got back from an easy morning run. It was slow, almost plodding, ended with a short stretching session, and in total took about 45 minutes. I did it because I need to shed a few pounds quickly and it’s the oldest trick in the book when it comes to fine tuning your weight loss.

I was reminding of this “trick” yesterday when my friend Ben brought up Dave Macleod using this tactic to get ready for his hardest routes. We used to run this tactic in college for track. As for climbing, before the most successful road trip of my life I’d tweaked a finger and had to back off on my training. Without the ability to train for strength I aimed instead for lighter (a roundabout way of getting stronger in gravity sports) by starting 3-4 days per week with 2-10 miles of easy aerobic-paced running. I ended up going into that trip 8 pounds lighter than my average weight, which increased my performance far more than any strength training could have hoped to.

Running in the morning before you eat helps improve your body’s use of fat for energy or, as Macleod puts it, “normally if I run I do it after the overnight fast to get into fat oxidation quicker”. A fasted state, while not optimal for hard training because you quickly run out of stored glycogen (or bonk, a point where your workout goes south quickly), is great for easy to moderate exercise because you can improve your body’s ability to tap into it’s “fat for fuel” process.

In general, light aerobic training has very little effect on your metabolic process. This is why you often hear trainers say things like “cardio only burns calories while you’re doing it where weight training burns calories all day long” and so forth. Aerobic training in a fasted state helps your training in two ways. It heightens your metabolism for a longer period of time than it normally would and it doesn’t break down much muscle tissue so you can utilize it during your hard training.

This is why when we recommend doubles programs one of your two workouts is always easier than the other. It’s not running that’s the magic pill here but aerobic training done in a fasted state. Running is efficient, since even easy running stresses the body more than most things, but any low-intensity exercise that raises your heart rate will work. For example, Cardio X was designed as the P90X doubles workout, which is why it’s much easier than everything else. If I don’t feel like going out, like I do right now because it’s raining so thankfully i'm already done, I’ll pop in a cardio vid instead.

vid: macleod on a 'run'. my runs are often similar. i don't generally (ever) solo 7B in my hiking boots but would guess well over half my runs are explorations that include a lot of off-trail rummaging around looking for rock, or whatever, which often includes technical climbing or, at least, scrambling over rock. you don't need to keep your heart rate at a steady state to get the effects of aerobic training. you just need to keep moving.

Great Article on Fasting

I've done a lot of fasting in my life. I've written a lot on it, too. This is one of the simplest scientific explanations about it I've seen. I gives you some science and minimizes the confusion. Here's an excerpt:

"Glycogen is necessary for thinking; it's necessary for muscle action; it's necessary just for the cells to live in general," says Dr. Naomi Neufeld, an endocrinologist at UCLA.

Neufeld says most adults need about 2,000 calories a day. Those calories make energy, or glycogen. Neufeld says it doesn't hurt — it might even help the body — to fast or stop eating for short periods of time, say 24 hours once a week, as long as you drink water.

"You re-tune the body, suppress insulin secretion, reduce the taste for sugar, so sugar becomes something you're less fond of taking," Neufeld says.

Eventually the body burns up stored sugars, or glycogen, so less insulin is needed to help the body digest food. That gives the pancreas a rest. On juice diets recommended by some spas, you may lose weight, but your digestive system doesn't get that rest.

Mark Mattson, a scientist with the National Institute on Aging, says that when we convert food into energy, our bodies create a lot of byproducts we could do without, including free radicals.

"These free radicals will attack proteins, DNA, the nucleus of cells, the membranes of cells," Mattson says. "They can damage all those different molecules in cells."

Fasting Article

If you don't want to read, there's also an audio link. Enjoy.