GYM BLOGGING: I’m off to a late start today because I’ve tried to return to my habit — which InstaPundit has interfered with — of going straight to the gym after dropping my daughter off at school.

That got me thinking about the dieting debate involving Megan McArdle and Jim Henley — as well as about John Ellis’s diet-blogging. Here are a few personal observations, which may or may not be worth anything.

First, the Body Mass Index seems worthless to me. Case in point: me. I’m 6′ 3″ tall. When I first started working out again over ten years ago, I weighed 194, which, according to the Body Mass Index calculator gave me a BMI of 24.2, which is healthy. Now, after many years of aerobic exercise and weight training, I weigh 210. That gives me an unhealthy BMI of 26.2 today. But when I started working out, my bodyfat was, if I recall correctly, 23.7%. Now it’s between 15 & 16%. My resting heart rate, always low, is lower than it was. My cholesterol is 150. I look better. And despite being at the computer a lot, I have fewer aches and pains than I had then. So am I really less healthy as the result of adding a good deal of muscle and losing a good deal of fat? I don’t think so.

Second, weight training is really important. Diet is important — you really can’t get in shape without paying attention to what you eat. But for me there’s nothing like muscle-building exercise to bring down body fat. Old-fashioned free squats are the single best thing: if I do them regularly, I get in better shape overall, and in particular the computer-related low-back pain disappears. If I stop for a while I can really tell the difference, in bodyfat and in how I feel. I don’t use a lot of weight — never more than bodyweight, and usually a good deal less. They even seem to help my knees feel better (as long as I’m careful to observe strict form). Other big compound exercises (curls, clean-and-press, etc.) have similar effects — old-fashioned, but effective. Aerobic/cardio work is important too (if I slack on that, I can see my cholesterol go up, and in particular my “good” HDL go down), but people seem naturally to pay more attention to aerobic exercise for some reason. Don’t neglect the weight training, too. This goes double for women, who need the bone strength it builds, and some of whom seem to worry about building too much muscle. Don’t worry — you won’t. And muscles on women are sexy, anyway.

I’ve long been an Atkins skeptic, and I’ve never done the Atkins diet. I do notice, though, that the more carbs I eat the hungrier I get. Protein and fat seem to satisfy me on fewer calories. Fortunately, I’d rather eat them anyway, and I’d rather have a small serving of protein than a big one of carbs. (My wife, like most women, feels differently.)

Anyway, for me it all goes back to a series of Bloom County cartoons in which Opus kept looking for gimmicks, oblivious to Milo’s advice of “eat less and exercise more.” “That can’t be it!” exclaimed Opus. It can, and it is. At least in my experience.