Wednesday, 4 January 2012

Does Exercise work for weight-loss? What's the REAL truth?

There are so many theories on weight-loss and exercise it's just not funny, and downright confusing for people that want - or need - to lose weight.

Might all this hard work be for nothing?  Read on...
Some say exercise is a vital component to the weight-loss formula - that you simply cannot lose weight without it.  Others suggest quite the opposite, that not only isn't it necessary, but that it doesn't even help.

It's time to examine these theories and give some straight answers.

Gary Taubes.
Who says what?
Gary Taubes has recently made a lot of waves suggesting you don't need to lose exercise to lose weight.  (Check out his article here or his blog for more from Gary).  He's mentioned this not only in his books, but he also got into a debate with Dr. Oz about the need for exercise on Oz's show.

Now I have a great deal of respect for Gary - especially as his writing have really made people think about conventional wisdom, and re-examine what they've been doing.  I believe some of his theories are bang-on, and I think others need further study.

Zoe Harcombe.
Along with Gary, Zoe Harcombe is another author who also speaks on exercise not being necessary, and recently went so far as to call it "a waste of time".  Check her article out here at her blog.

I also have huge respect for Zoe.  First, Zoe is a qualified nutritionist who actually speaks out against the conventional dogma nutritionists usually recite - you know the dogma - whole grains are good, fruit is good, potatoes good, saturated fat bad, yada yada...  To her credit Zoe is one of the few nutritionists I've ever heard of that teaches the truth about carbohydrate and saturated fat.  Her work in obesity-research is fantastic and she's done wonders changing the lives of obese (now formerly-obese) people.  If you haven't checked out her blog, do so. 

On their opinions regarding exercise though, I can adamantly state Gary and Zoe are absolutely wrong.  And they're also right.

Explain Yourself, Crazy Person!
I know, it sounds crazy, doesn't it.  But be patient and I'll explain it.  First, lets talk about why they're correct.

I'll use myself as an example - because I was obese.  Just before I added exercise into my weight loss effort, I was a 45 year old, 300lb obese man about 6' 3" tall.  My BMR (Basal Metabolic Rate) was 2,591 calories (remember that number, it's important) according to the most standard calculation method used.  For those that don't know, a BMR is the number of calories (unit of energy) you require if you were on bedrest 24/7.  You add to that your needs for other activity to get your total caloric needs.

With my other daily activity factored in, I'd need to eat in the neighbourhood of 3,300 calories a day to maintain that weight - So I figured I'd eat around 2,800 calories to lose that magic pound a week (that's a myth for another blog) and that's what I ate.  So boom, I had a caloric deficit of 500 calories a day.

Now, lets say I decided to add an hour of walking into my routine, at say 3mph.  Walking is the most-recommended exercise that people starting a diet undertake, and the one most often recommended by health-care providers.

As it turns out, a 300lb person walking for an hour burns (according to several online calculators) approximately 449 calories.

Yay! Almost double my deficit, right?  Wrong.  Every calculator available AND all those 'calories burned' counters on exercise equipment show you the calories with the BMR factored in.  So that 449 calories, minus my hourly BMR (2591/24 = 108) is now only 341 calories.  Still, that's a big deal, right?

Or is it... conventional wisdom holds that a pound of fat equates to 3,500 calories - If I did that exercise 3 days a week I'd lose an extra 1.26lbs a month.  That's it.  Well, until I lost more weight... then the calories I burn goes down even more.  At 250lb I'd only burn 279 calories after adjusting for new weight/BMR.  That's only 1lb a month.  At 225lbs (still overweight) it's only 247 calories, and the number continues to drop.

It's even worse if you use the example of a 160lb overweight woman.  She'd only have a 120 calorie deficit after a full hour of walking 3 miles per hour.  That's only .44lbs per month / 5lbs A YEAR.

Nobody I know gets excited about 1lb a month.  Less than half a pound a month is just laughable.  So in these examples, Taubes and Harcombe are absolutely correct.  There's no doubt about it.

However ... here's where they're just plain wrong
The key to exercise for weight-loss is intensity.  Vigorous exercise is what loses weight.  Not moderate/easygoing exercise.

Granted, it can take a while to get fit enough to do vigorous exercise for any length of time, but it has so many benefits it's just worth it.

Lets use my 300lb, 45-year old example again. Lets say he hops on an exercise bike and gives it his all for a whopping 15 minutes.  At a very vigorous intensity, this works out to 408 calories... slightly less than an hour of low-intensity walking - but because its only 15 minutes, it's burning 381 calories after BMR is factored in.  That's more than the 1hr of walking.

Yes, 15 minutes of vigorous exercise can be difficult, but it's attainable, and as fitness improves, so can the length of the exercise.

Once the exercise is up to an hour - again, of vigorous exercise - things change dramatically.  60 minutes of intense cycling 1,633 calories.  Subtract the hourly BMR and that's still 1,525 calories.  That's an extra 5.5lbs a month, nearly 70lbs in a year.

Oh, an obese person could never do that!
Not true.  It's completely attainable. I know because I did it.  At 45 years old and with serious spinal issues I did it.  I don't think I'm any more able than anyone else.  Even if you can't do as much work as hard as I did, do what you can and your fitness will improve.

As fitness improves, so does your ability do workout more vigorously.

The Bottom Line
So, in regards to moderate exercise, Taubes and Harcombe (and anyone else that says exercise doesn't matter) are right.  It honestly just doesn't do much.  Even when severely obese, it helps about a pound a month IF you can do three full hours a week.

If, however, you do vigorous exercise (and you may need to work up to it, I started at about 5-10 minutes every other day) you'll burn as much as 5.5x the calories as moderate, maybe more.  One pound a month isn't much.  5 to 6 pounds a month is huge.

But 3500 calories = a pound is an unproven theory!
Even if you don't subscribe to the 3500 calories = a pound theory (and I don't - nobody knows exactly how many calories = a pound of fat) you can't discount that vigorous exercise burns more than five times as much energy as moderate; the math holds true.  As such, regardless of how many calories = a pound of fat, you're still losing them much, much faster with vigorous exercise than without.

And for some inspiration, check out this guy:  His name is Ben and he did a great job losing weight.  I don't know what Ben ate, and I don't care.  He exercised vigorously and lost weight.  He also made a great, inspirational video.  Good going, Ben!


1 comment:

  1. I had watched a while some experiment comparing High Intensity Training vs. Low on TV... In that one, the HIT girl "won" (the girl lost more weight, a lot faster and was a lot fitter than the one in LIT). I was trying to check about that, but I couldn't find much information, and that's because I was missing this "BMR"... lol
    That's important info that I think the average person isn't aware of.
    Keep the good work!