How much do you have to move for weight loss?

Losing weight has always been basic math to me.  The calories out have to be more than the calories in.  For years, we have heard, to burn fat you must use cardiovascular exercise and for durations longer than 30 minutes.  Strength training is helpful because it will raise the level at which your body burns calories while at rest.  That is what I was taught anyway.  That is the mentality I used all summer to lose weight.  In fact, I  park my booty on the elliptical with my nook reader for 45-50 minutes and I actually enjoy it.  And then I read this article: Lower Caloric Expenditure = Better Weight Loss Results? in the IDEA Fitness Journal, January 2012, page 15.  (I tried to link to it, but it is a professional journal and unless you buy a membership you can't view the article online.)

The article discusses a study that took place at the University of Copenhagen in Denmark.  The scientists tested the differences in workout length and caloric expenditure and how it affected weight loss.  Sixty-one moderately overweight young men were separated into 3 groups for thirteen weeks.  The three groups included: non exercisers, moderate exercisers (about 30 minutes or 300 calories burned) and high exercisers (about 60 minutes and 600 calories burned).  The participants were instructed to maintain their current dietary intake.  At the end of the study, the moderate exercisers had shed and average of  8 pounds of body weight and 8.8 pounds of fat.  The high exercisers lost an average of 6 pounds of body weight and 8.4 pounds of fat. 

So basically, the high exercisers worked twice as hard, but had the same results as the moderate exercisers.  Hmmm...makes me wonder why I am spending 45-50 minutes on the elliptical, if I could get the same results in 30 minutes.  Time for me to look a little closer at the current recommendations.

In February of 2009, ACSM (American College of Sports Medicine), aka the gold standard in the fitness industry, released a Position Stand regarding "Appropriate Physical Activity Intervention Strategies for Weight Loss and Prevention of Weight Regain for Adults".  The recommendations issued by the ACSM are as follows:

For Weight loss: 150-250 minutes/week of moderate-intensity physical activity provides only modest weight loss. Greater amounts (ie. >250) provide clinically significant weight loss. 

What does that say to me?  250 minutes divided by 5 days a week = 50 minutes of moderate intensity exercise.  So the 45 minutes, 5 days a week that I have been putting in do follow the current recommendations.

All that being said, weight loss still goes back to basic math.  To lose weight, your body must burn (or metabolize) more calories than what you are eating.  A calorie is a unit of energy. Specifically, a calorie is actually a kilocalorie and it is the amount of energy, or heat, it takes to raise the temperature of 1 gram of water 1 degree Celsius. (I feel like Charlie Brown's teacher here.)  You increase the number of calories you burn through exercise. Higher intensity exercise will certainly burn more calories than lower intensity, but higher intensity exercise cannot typically be maintained for long durations of time. 

I think that this study proves how important diet is in the weight loss equation. There was no change in the dietary intake, the weight loss recorded was with exercise alone.  Six to eight pounds in 13 weeks, is about 1/2 pound a week.  For most people, I am not sure this would be enough of a loss to stay motivated. 

At this point, I am not ready to give up my long duration exercise just yet. I am reading a ton of good books.  I will continue to follow the ACSM recommendations, though I will begin to interval some higher and lower intensities into my workout.