I've been blabbing a lot lately about doing triathlons. Almost annoyingly, I admit. And if you think you've got it bad, try being my wife. Well, that might be illegal and weird, so we'd better not try that.

Anyway, I've been preaching the benefits of exercising and about my new multisport hobby so much — even to the point of trying to convert, er, convince others to "tri" 'em — that some might wonder if I've been called on a triathlon mission.

FYI, I haven't.

For the record, if somebody wants to extend such a calling and the destination is Kona, Hawaii, I just might do it — preferably not in a suit and tie.

Though I've become sold on exercising in general (who'da thunk it?), I relearned a valuable lesson this past week regarding physical activity and weight loss.

Moving your body is great and all, but the scale sometimes just doesn't care how much you exercise and how much weight you think you should have lost if your mouth also keeps moving in a munching motion.

Sadly, calories are harder to sweat off than to swallow.

It's almost an unfair equation, really. Consider this comparison: A single serving of one of my favorite candies, Reese's pieces, has 200 calories, but my 220-pound body would have to run/jog/waddle like E.T. about 1.4 miles to burn that much fat fuel, caloriesperhour.com claims.

Now, it would take me approximately 1.5 seconds to inhale one serving (about 50) of those scrumptious "Peanut Butter Candy in a Crunchy Shell" mouth-pleasing morsels. Maybe a full two seconds if I listened to my mom and slowed down to taste and enjoy my food.

But getting my short, chunky body to travel 1.4 miles on its own power would take about 16 minutes of running. Maybe 15:30 if I pretended an Olympic gold medal or 50 more Reese's pieces were on the line.

By my calculations, that means it is approximately 640 times easier to gain weight than to lose it. And if you think about it, running 1.4 miles would only offset the handful of candy. And who can stop with just one handful anyway? So now you've got the multiplying effect of several handfuls. Plus, once you've eaten that much candy, who even feels like running?

That makes gaining weight infinitely easier than losing weight by just exercising. Especially if you put pi in the formula.

I re-realized this when I stepped onto the scale Monday. The chart on my bathroom wall kindly showed that I'd lost four pounds the previous month, which included me training for and doing two sprint triathlons.

But after just five days of vacation — where I left work, the world and my will power behind — the mean bathroom scale unkindly showed that I'd regained all four of those pounds. Boom! Welcome back!

This wasn't just a sit-under-the-coconut-tree vacation, either. I swam a bunch. I even made a mini-jogging course on a Lake Powell beach and ran for 30 minutes one morning. And I biked 60 miles right before leaving.

But because I experienced portion distortion and overindulged in junk food and treats — foolishly trying to convince myself that my "workouts" would ease the pain at the scale — I gained weight.

Lesson re-re-learned.

Even while not vacationing, I often fall into a trap of thinking I can eat more because I exercise. Problem is, it's easy to overestimate the benefit of a workout and to underestimate the damage of a pig-out.

Guess that's why some experts suggest we exercise for health and watch what we eat to lose weight. And all the better if we can do both at the same time.

Despite his vacation, sports writer Jody Genessy has still lost/kept off 151 pounds. His weight-loss/fitness column runs every other week.

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