Do You Know Your Calories?Thursday, December 16, 2010
As I have blogged before, obesity is the physical manifestation of positive caloric balance and trying to manage your (or your clients’) weight without understanding (or teaching your clients) calories is like trying to balance your bank account without understanding money.
Just imagine wanting to balance your bank account without any concept of how much money you make, what the bank charges to handle your money, and how much money you spend each month.
Similarly, trying to manage your “calorie account” without any idea of how many calories you are eating (or drinking) in relationship to how many calories your body actually needs is probably not the smartest way to go about managing your weight.
So do people with excess weight understand calories and do they have realistic perception of the caloric deficit required to achieve their weight-loss targets?
This question was addressed by Gregory Kline and Sue Pedersen from the University of Calgary, in a paper published in Diabetes Obesity and Metabolism earlier this year.
In this study, 130 subjects with type 2 diabetes participating in a weight loss trial were asked how much weight they would like to lose and to estimate the caloric deficit required to achieve this weight loss.
Notably, all subjects had previously received dietary teaching from a dietitian and a nurse at a diabetes education center.
While the desired weight loss ranged from 4.5 to 73 kg (average 26.6 kg), only 30% of participants were willing to estimate the caloric deficit required to lose their target weight.
Among participants, who dared estimate the caloric deficit required to lose one kilogram, answers ranged from 0.7 to 2,000,000 calories/kg (median 86 calories/kg).
Nearly half the subjects (47%) underestimated the total required caloric deficit to achieve their target weight loss by more than 100,000 calories!
Thus, as the authors note,
“Despite attendance at a diabetes education centre, this population of obese individuals had a poor understanding of the quantitative relationship between caloric deficit and weight loss.“
My guess is that many health professionals, who recommend weight loss to their clients, are probably not much better at estimating total caloric deficits than the participants in this study. I would imagine that few of the health professionals, who nonchalantly recommend that a patient go lose 50 lbs (e.g. before hip surgery), actually realise that they are prescribing a 175,000 calorie deficit (or almost the total number of calories that the average person would consume in three months).
This is why I maintain that a minimum degree of caloric literacy together with at least a basic understanding of calorie homeostasis is important for anyone trying to manage their weight and is definitely something I would expect of anyone recommending weight loss.
While regular readers of these pages will well appreciate that I certainly do not subscribe to the notion that weight management is simply a matter of calories in and calories out, I do believe that understanding calories is a prerequisite for any meaningful discussion about weight management.
p.s. One kilogram corresponds to approximately 7,000 calories – one pound corresponds to approximately 3,500 calories.
Kline GA, & Pedersen SD (2010). Errors in patient perception of caloric deficit required for weight loss–observations from the Diet Plate Trial. Diabetes, obesity & metabolism, 12 (5), 455-7 PMID: 20415695