Want to see the latest shenanigans with statistics?
Check out the data presented at the North American Association for the Study of Obesity (NAASO) conference this past weekend - as reported by Fox News in their online article, "How Much Exercise Sparks Weight Loss?" - presented by Dr. John Jakicic, a Professor of Health and Physical Activity at the University of Pittsburgh.
For two years, Dr. Jakicic has followed more than 200-obese women (average age 37, average BMI 32 at the start) on a calorie-restricted diet and varying exercise routines:
- average calorie intake = 1,200 - 1,500 calories per day
- Fat intake restricted to 20-30% of calories
- moderate amount/moderate intensity
- moderate amount/vigorous intensity
- longer amount/moderate intensity
- longer amount/vigorous intensity
- those following the "moderate" regiments burned about 1,000 calories per week from exercise
- those following the "longer" regiments burned about 2,000 calories per week from exercise
Now the findings were interesting, body fat percentage lost:
- longer amount/vigorous intensity = 7.2%
- longer amount/moderate intensity = 6.5%
- moderate amount/moderate intensity = 4.9%
- moderate amount/vigorous intensity =3.7%
But, what's wrong with this picture?
After two years these women only managed to lose between 3.7% and 7.2% of their body fat? How is that even possible given the calorie restriction and calories burned in exercise?
It's not!
If the calorie theory is applied, these women should have lost a lot more weight over two years.
Forget the statistics - Just do the math!
We know the average age was 37....we know the average BMI was 32....let's assign a height of 5'7" as our baseline here, which means a body weight of 204.5-pounds at the start of the study for a "pretend" participant we can use as our baseline to do the math. You can double-check my assumptions with an online BMI calculator at the CDC website.
We do need to know something else though - what is the calorie intake at the start to maintain body weight of, let's just say, a completely sedentary person of this height and weight? For this number, we need a Basal Metabolism Calculator, which can be found online at Room 42's website. Here we find a "couch potato" needs 1,865-calories per day just to maintain her weight.
So, we have some good numbers to start with.
Now let's do the math. Let's assume she eats the higher calorie average - 1,500 per day. And, also let's assume she wound up in the group burning just 1,000 calories a week for her exercise. How much weight should she have lost if we apply the calorie theory?
Oh.....92.28-pounds in two years!
That's right - 92.28-pounds!
Remember, the calorie theory is all about "calories in, calorie out."
Calories in = average 1,500 per day...this represents a calorie deficit of 365-calories each day. But, let's call it 300-calories just in case she under-reported her food intake.
300-calories per day X 365-days = 109,500 calories x 2 years = 219,000 calories
219,000 calories divided by 3500-calories per pound = 62.57-pounds
Now we have to factor in the exercise calories burned each week.
1,000 calories per week x 52 weeks = 52,000 calories x 2 years = 104,000 calories
104,000 calories divided by 3,500-calories per pound = 29.71-pounds
Add them up...
62.57-pounds + 29.71-pounds = 92.28-pounds theoretically lost if the calorie theory holds true.
What happened? Where's the expected weight loss?
Yup - another hole shot right into the Calorie Theory - and no one is paying attention since the "stats" used look good enough.
Well, "good enough" here simply isn't good enough. When you see statistics thrown around like this, without real pounds and hard numbers assigned to fat pounds lost - do the math!
Posts
>>>Her resting metabolism at 140 would be more in the range of 1,500 calories, plus or minus (11 calories per pound, more or less).<<<
ReplyDeleteTo calculate her calorie requirements at her higher start weight, as a couch potato, I used her active metabolic rate, not her resting metabolic rate as the determinant of calorie deficit potential (theoretically since she is a made up participant).
Because she increased exercise consistently, her active metabolic rate increased, even with the weight loss. That is the calorie requirement that counts in weight loss - the deficit created from all the calories you burn from basal requirements and your activity - your active metabolic rate.
At a BMI of 32 to start, even with horrible body fat percentage, we're talking about probably a potential of 33% body fat - or at a start of 204 pounds, 67.3-pounds of fat weight.
The maximum loss in the two years was just 7.2% of body fat - nowhere near 65 pounds of body weight, even if you calculated a high loss of lean body mass.
The results here remain unimpressive - and disconnected from the calorie theory that holds the deficit should create a parallel loss in weight over time.
>>>Are you just going from the newspaper account? In college I worked in the medical library and had the opportunity to read journal reports and newpaper accounts side-by-side. Long story short: I'd get a copy of the original study if I were you. I find that most researchers will gladly e-mail a PDF if you ask.<<<
ReplyDeleteYou might want to read some more of my blog to understand how adament I am about going directly to the data and not relying on secondary sources for interpretation of the data.
>>>I'm not sure what you mean by "calorie theory," but it sounds a little ... paranoid/conspiracy theoryish.<<<
ReplyDeleteA quick google search will provide you with enough definition that explains how deeply rooted the "Calorie Theory" (calories in - calories out) is within the medical, dietetic and scientific community - not at all conspiracy theory or paranoia - it is what it is.