Wednesday, January 6, 2010

another day in fitness-land

it may be self-indulgent to share one's personal or professional endeavors and thoughts on a daily basis. that's what blogging is about. but sometimes you actually have much to say that would be beneficial for others to hear.

this past summer, TIME mag ran a piece that was very controversial, esp among fitness people. the writer found some exercise physiologist(s) willing to address the thesis that exercising may actually lead to excess caloric consumption, leading to weight gain or retention. this raised a firestorm in the field such that the ACSM sent out an email to its members suggesting we counter these claims by writing to local press. unfortunately, the ACSM's bullet points did not refute the thesis; it merely declared that exercise is essential to healthy weight loss/management and that exercise is healthy in many other ways. but it did not counter the idea of the article that diet is essential for weight loss. i, unfortunately for the profession, actually concur with the TIME article. here's why....

an article in, i believe, the ACSM's flagship journal, Med Sci Sports & Exercise, this very year found that long distance runners lose weight because they tend to not eat enough calories. by 'enough calories' what scientists mean is calories to match your basic and activity-based needs. for example, let's assume you need 1600 cals/day just to lay in bed and hold weight - this is your BMR, or basal metabolic rate. then, you need about 300/day to do normal activities - eat, toilet, sit at work, etc. now, if you are active, say you run an hour/day, you burn about 400-800 (you're a real athlete at these higher numbers) per day over and above the 1900 you otherwise needed; that's, for simplicity sake, 2500 cals/day. most athletes do eat enough but those who lose weight were found to actually not eat enough. whatever reasons one might conclude - fatigue, loss of appetite, attempt to lose weight and therefore watch calories (all listed in a nancy clark, r.d., article in the ACSM's FitSociety newsletter this winter) - if you don't eat enough to compensate for your needs, you will lose weight. duh!!

so what can we conclude: exercising weight off is hard to do, and invariably requires you not enough to replace the calories you burned off. hence, only dieting loses weight.

but, the hard truth is, only by exercising, along with watching excess calories, can you retain your lean muscle tissue, assist in elevating overall metabolic rate both after exercise (EPOC- exercise post oxygen consumption), and develop life-long healthy habits, can you lose and maintain weight. so, what i would suggest is that exercise be promoted for the benefits we all know about, and that it be used to bolster a healthy, reduced-calorie dietary regime one can sustain throughout life, not just for the big weekend up ahead.

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Dr.Irv