Calorie Needs & Expenditure
Just a quick follow on post to my previous one on caloric needs inspired by a recent diet comparison RCT.
In comments there, Yoni Freedhoff of Weighty Matters blog (and author of the new book The Diet Fix: Why Diets Fail and How to Make Yours Work) made the following comment:
Here's a link to the study he was (correctly) recalling: Comparison of Predictive Equations for Resting Metabolic Rate in Healthy Nonobese and Obese Adults: A Systematic Review. (unfortunately not free access)
The Mifflin-St Jeor equation is more likely than the other equations tested to estimate RMR to within 10% of that measured, but noteworthy errors and limitations exist when it is applied to individuals and possibly when it is generalized to certain age and ethnic groups. RMR estimation errors would be eliminated by valid measurement of RMR with indirect calorimetry, using an evidence-based protocol to minimize measurement error.
For comparison, the average REE in "the study" for 60 y.o., 5'4", 190 lb women was about 1300 calories/day (measured by indirect calorimetry). The average TDEE of about 2300 calories/day after measuring PAEE with an activity monitor and adjusting the total for TEF. Lastly, the reported intake was 2000 cal/day.
What does the Mifflin-St Jeor equation predict? This calculator uses this equation, and I've screenshot the results.
Using the equation, BMR is calculated at 1355 cal/day.
I have no way of knowing, but since the physical activity would have had to be quite rigorous to achieve a TDEE of 2300 with an REE of 1300, I tend to think the activity monitor was the problem in that study.
Want more information on the Mifflin-St. Jeor Equation? Here is a link to the (full text) of the paper about its derivation: A new predictive equation for resting energy expenditure in healthy individuals. On page 245 is my "money picture" -- this is the one I remembered but could never locate again! Thank you Yoni!!
LOOK AT THAT SCATTER!!!!!
LOOK AT THAT SCATTER!!!!!
This is what I'm talking about, and it's not about dissing the predictors even, it's about predictions for the mean vs. predictions for the individual. Pick a weight or lean body mass and scan a vertical line up and see the range. On the flip-side, pick an REE and look at the range of people whose total or lean mass share the same resting energy needs.
It IS true that self reported dietary intake tends to be lower than measured by doubly labeled water technique. But it doesn't have to be. That's like saying you are incapable of weighing and measuring ... I know you are not. This is not to say that most can, or even should, do this for all eternity. But to get a handle on TDEE, if you can't get an REE measurement for a starting point, knowing your current intake is probably the next best thing.
More to come ...