I wasn't originally going to post about exercise for fat loss, but a comment left on the last post led me to reconsider.
Why wasn't I going to write about this? Well, the unfortunate fact is that exercise alone is a pretty poor way to lose fat.
If you're gasping in shock right now, I understand - the popular media (and gym owners all around the country) would have you think that sweating away on a treadmill is the quickest route to abs of steel and glutes of zinc (or whatever). But it rarely works, because most people, when they try to just exercise, compensate by eating more and end up losing little to no fat. It's really easy to out-eat even a very vigorous exercise program. Burning 1,000 calories is a LOT of work, but eating that much food is pretty easy, especially if you're the sort of person who got fat to begin with (meaning, you're not exactly a light eater).
Having said that, I would also say that dieting without exercising presents its own drawbacks. If you cut calories without exercising you will lose unacceptable amounts of muscle mass, which has long term negative effects on performance, health, and your ability to keep losing fat. I personally also find that if I'm exercising while restricing calories the exercise helps blunt my appetite (this phenomenon is not supported in the literature, but it absolutely works for me, so take what you want from that).
So if you are watching what you eat (details to come in another post), exercise can serve various functions. First, you must exercise to preserve muscle - you want your body to burn your stored fat for energy, not your muscle. Exercise will also burn calories, both during and after the workout, which will accelerate your fat loss if you are eating properly. Exercise may blunt your appetite, or at least motivate you to maintain the strictness of your diet.
The next question is which type of exercise will serve these functions best. If you answered hours of steady state cardio (otherwise known as LSD for long slow distance, or long slow death), then you're wrong. There are many reasons why hours on the treadmill won't get you ripped - your body gets more efficient at a movement the more you do it, reducing the calories burned; you tend to sustain injuries from doing long term repetitive movements; chronic overexercise will jack up your cortisol levels, messing up your metabolic rate. Hours on the treadmill will also make you a worse martial artist. Muscles forced to move slowly for long periods of time get good at moving slowly for long periods of time - it's called specificity of adaption. You don't want muscles good at moving slowly over long periods of time - fights are quick and fast, and you want quick and fast muscles.
So what should you do? Metabolic conditioning and high intensity interval training are all the rage in fat loss programming. There are great sources available for details on how to do these, but the core of both is short bursts of very intense activity - moving fast, or with a heavy load - interspersed with short periods of rest. In short, do things you can't do for very long (anywhere from 20 seconds to a minute or so), rest, repeat. Run sprints, jump rope for 30s, then rest for 30s, repeat, do sets of dumbell snatches, something like that.
One could argue about the best interval/ rest ratios or whether complexes are better than bodyweight sequences, but I doubt we'd find huge differences between the different protocols. Making sure your exercise is intense makes sure your body holds onto its muscle mass. It also encourages your body to burn calories far after the session is over (called EPOC, I believe), which means you burn more fat.
If you've been following this blog you might notice that these protocols are not only good for fat loss, they're what I recommend for improving your endurance. They also closely mimic many martial art classes. Think about it - you do a few techniques, very intensely, then get some pointers from the instructor, then repeat. Do a bunch of pushups, then stretch, then a bunch of leg raises, stretch - it's all high intensity intervals. In other words, if you're a martial artist looking to lose fat, you should already be doing the exercise that helps you lose fat. So why are you still fat? That comes right back to diet (and another post).
I will add one more complication to this mess. Remember when I wrote that long, slow cardio was not good for fat loss? Well, I lied. LSD is a bad foundation for a fat loss program. Getting onto a treadmill and sweating away for an hour is not a good basis for your fitness regimen. It is both too high intensity (causing wear and tear and a stress response in the body) and too low intensity (not intense enough to preserve muscle or boost metabolism). You HAVE to do high intensity work first and foremost, for the reasons I described already. But once you've got that base covered, you can't just keep adding in more and more high intensity work and lose weight faster. You're going to overtax your body if you try - your recovery ability is limited, especially if you're restricting calories. You can't do serious metabolic conditioning every day without getting hurt and overstressed.
So what if you want to lose fat faster and you're at the limits of your own recovery? Add in some very slow work into your program. What doest that mean? It doesn't mean jogging on a treadmill. It might mean casually walking your dogs - not power walking, not racing around with a heart rate monitor, it means moving casually for a period of time - up to a couple of hours - slowly enough that you're not sweating profusely or out of breath, yet you're burning more calories than you would sitting on your couch and watching TV. Your muscles won't adapt to the exercise (won't get slower) because you're not going to work hard enough to force any kind of adaption - you're working so far within your ability that your body doesn't need to change, other than by providing the fuel for the activity.
Want to really lose a lot of weight, fast? Get one of those weird treadmills that goes veeery slowly and put it at your desk. Spend your entire work day walking at, say, .5 mph. Or park one of those weird little portable pedal setups - like a tiny little exercise bike that you put on the floor in front of your chair - and pedal away, very casually, all day long. You can get your body to burn calories constantly the way skinny people do (they do it by fidgeting, but I don't think one can learn to be a fidgeter).
The trick to this is to understand that the long walks or all-day-low-intensity-activity won't get you in shape, it won't keep muscle on, and it won't make you better at karate. It will help you lose fat, as long as your diet's in order. It will also make everybody in your office think you're crazy, so beware. Give it a try and post to comments if you get anywhere!