Fasted exercise - Matt Metzgar

Matt Metzgar

Fasted exercise - Matt MetzgarSeptember 18, 2011

Running on Empty

I've noticed a couple curious things lately in regard to eating and exercise. First, I've noticed that if I ocassionally skip dinner, or just have some carbs like potatoes but no meat for dinner, that I actually feel better upon waking the next morning. Of course, I'm not doing this every day, but if I do this once or twice a week, then I am virtually guaranteed to feel better the next morning. This points to how occassionally restricting calories in the evening, or perhaps restricting protein in the evening seems to yield benefits.

Today, I noticed how this carried over into exercise. I have been exercising fasted in the morning, going for an intermittent run on the nearby trail. Last night, I just had some potatoes instead of dinner, and this morning I ran before eating anything. This combination seemed to really prime my body for running. I don't know if it put me in "fat-burning" mode or something, but I was just really cruising on the trails today.

It's amazing how good you can run on an empty fuel tank. I wish someone would have told me about this 15 years ago. I remember reading Runner's World for a few years straight back in my twenties. Never once did I see an article that recommended running while fasted. Guess it wasn't the expert publication it was supposed to be!

Skip breakfast, then lift weight to burn fat

Return from Vienna: Fixing the Damage, Part 1 | Dangerously Hardcore

Extract:

Let’s recap. Skipping breakfast accelerates fat burning, spares lean tissue and prevents the formation of new fat cells. Eating breakfast—specifically a traditional breakfast containing copious amounts of carbs—creates new fat cells, stops fat burning and triggers the destruction of lean tissue if blood sugar levels fail to rise high enough.

Cortisol levels naturally rise through the evening and peak around wake-up time. Cortisol, as you know, catabolizes body tissue, which can include muscle, but only if certain signals in the body direct it to do so. The specific signal: elevated insulin levels and high cortisol levels. That high-carb breakfast switched on the potential to burn muscle (although what happens in most cases is far worse, but I’ll get to that in a second).


If cortisol acts alone, in the absence of insulin, it forces the body to preferentially burn body fat; this is the exact scenario you find yourself upon waking, if you don’t screw it up by eating carbs. And if you don’t eat anything, or very little, cortisol continues signaling the release of body fat for metabolism, just as it did through the previous hours of snoozing.

Let’s say that you don’t care because you’ll ensure you eat enough carbs so that muscle won’t get burned. You want to build muscle, lots of muscle and you want to do it now; extra cardio can burn off the fat. Slow down, killer. There’s another problem with high insulin levels plus high cortisol levels. When the two are elevated together, the body gets another signal: start making as many new, empty fat cells as possible—the max number of which being determined by how much body fat you already have stored, the more fat, the more empty fat cells created.