Inactivity ...... Was : Re: 11 miles a week

[Guest guest]

Hi folks:

I have done a quick skim of the article and a fairly close look at

their data in this study and have some comments. Based on these data

my conclusions are considerably different from those of the authors

of the piece. The *principal* conclusion I draw from these data is

that, if these results are typical of the kind of results that can be

had from jogging 693 miles in eight months, then exercise is a very

much more useless way of losing weight than I had previously believed.

Here are the facts as I see them. While the authors appear to be

implying that eleven miles of exercise a week is necessary to prevent

fat build up, they completely ignore the possibility of restricting

food intake. Certainly it is interesting to examine the effects of

exercise, and I applaud such efforts. But to make a statement

like: " Significant gains in visceral fat in only 6 mo emphasize the

high cost of inactivity " is ridiculous, imo. Of course we all know

here that is it not the lack of physical activity that is the

problem, but an imbalance between energy intake and energy

expenditure, of which physical activity is only one component.

The subjects averaged 50 to 55 years of age; BMIs averaged 29 to 30;

body fat percentages do not seem to be disclosed - a major omission I

think. Their diets were surprisingly low in protein - 15% of

calories - while fat was 30% to 35% of calories.

The unexercising control group ate 2047 calories per day, and put on

two pounds of weight in ~183 days, all of it fat. Unmentioned is

that if the control group had instead consumed just 38.3 calories

less per day - the equivalent of about one-third of a medium banana -

they would not have added any weight or fat. Hence the apparent

ridicularity of the quotation (above) from the abstract.

In contrast the heavy exercise group, the members of which each

jogged 693 miles in ~243 days, ate a mere 25 calories daily more than

the control group (while their extra exercise was presumably burning

off almost 300 extra calories!!!!) so who in hell would be surprised

if they had lost weight, and that some of that weight lost had been

fat????

What is really startling about this exercise group is that they lost

a great deal less weight than the regular criteria for the

relationship between weight and exercise would suggest. Here are the

numbers:

They do not seem to have specified the speed at which they jogged.

So lets just assume they burnt 100 calories per mile. For 693 miles

that is 69,300 calories which converts, using the conventional wisdom

(which I have no reason to doubt), to 19.8 pounds of weight loss.

The controls' energy balance appears to have been 2009 calories per

day - 38.3 calories a day less than they had consumed. Presumably

the exercise group's energy balance, sans exercise, would also have

been 2009 calories per day (that is what a control group is for).

But they in fact ate 2072 calories. This excess of 63 calories

daily should, again sans exercise, have resulted in a weight gain

over the eight months of 4.4 pounds (2072 - 2009 calories) x 243

days/3500.

So, WITH the exercise their weight loss SHOULD HAVE BEEN 15.4 pounds

(19.8 - 4.4).

How much weight did they in fact lose? JUST FIVE POUNDS IN TOTAL,

of which 3.2 pounds was fat and 1.8 pounds was lean body mass.

Clearly I cannot explain precisely where their discrepancy lies. If

someone thinks I have made a mistake in my calculations please say

so. But it appears that, at least in this particular study, jogging

was about one-third less effective for weight loss than we are led to

believe it to be, assuming 100 calories burnt per mile.

They also found, incidentally, which is useful, that this group lost

the same percentages (~7%) of both visceral and subcutaneous fat.

So in conclusion, surprise, surprise, a massive daily energy deficit

resulted in the loss of some (not much) fat. My choice would be to

instead forgo half a banana - after all we do know I think pretty

much for certain that restricting calories is highly beneficial.

But for those who choose to jog 2.85 miles a day, every day for eight

months, come heatwave, blizzard or whatever, in order to lose a mere

3.2 pounds of fat ................. be my guest.

Rodney.

> Hi all,

>

> That's just the distance you would need to walk or run (it seems

> either intensity doesn't matter here) for preventing accumulation

of

> that diabetes promoting visceral fat.

>

> Just two notes about the paper: they didn't have a high amount low

> intensity exercisers because they would be walking for more than 8

> hours a week, and was not easy to fing volunteers. Another point to

> look at is that non exercises were gaining visceral fat in spite of

> they weren't gaining neither body weight nor subcutaneus fat!!

>

> http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?

> cmd=retrieve & db=pubmed & list_uids=16002776 & dopt=Abstract

>

> http://tinyurl.com/a4j3a

>

> Cheers.

>

> Willlie.