Right after my promotion to shodan years ago I realized somebody slipped up in the ordering department when I tied my new black belt around my waist. I've always taken a size 5. Maybe my instructor thought I would grow into the size 9 that was now dangling halfway down my shins. Fortunately he had a 5 on hand. "I hope it fits like a bow tie" he remarked. Funny guy. It didn't, and I'm happy to say it still fits just fine. I'm wondering how many masters have had to pick up longer belts through the years to accommodate an increase in midsection girth. It's a bit disheartening to see a 6th dan walking around with a build like Chris Farley.
Obesity has become the new disease for the modern age. At no other time in history have so many people been so overweight. Much of this begins during childhood, and legislation has already been passed to remove vending machines filled with "bad" snacks from public schools. Healthy treats such as low glycemic fruit juices and other fat free items are available. But overindulging in anything, even if it's touted to be good for you, defeats its original purpose.
I remember seeing an ad for a local martial arts school chain that displays the now trite before-and-after images of flab to firm washboard abs, courtesy of karate training. Almost every exercise gizmo on the infomercial market targets the stomach. You can do crunches and leg raises until you're blue in the face, but if you're taking in more calories than you can burn the excess gets stored as body fat. Nevertheless, working the midsection is imperative as it is the seat of the hara. Having strong abdominals also offsets the possibility of wrenching the lower back, another ailment of the masses.
In addition to the all-important diet, I strongly advocate some kind of progressive resistance training. Some myths regarding weight training don't die easily. One martial artist wrote online that he felt bodybuilding was detrimental because eventually the hard earned muscle could turn to fat! This isn't even remotely possible.
There's so much information available on proper diet that I won't bother getting into that here. I will say that certain faddish diets do more harm than good. Low carb or crash diets may cause a rapid decrease in weight, so much in fact that lean body weight (i.e. muscle) is sacrificed, thereby slowing one's metabolism. As such I don't believe in any type of radical dieting.
These height and weight charts that I've seen are speculative. If you're eating properly, training consistently and getting adequate rest you're doing good. Still, I like to cheat now and then. And who doesn't? Recently I indulged myself with something called a Frappuccino. Unbelievably good. Lots of caffeine, sugar and cream. Look, if you're going to be bad do it right!