Originally Posted by
bruce19
Did a little research and according to Dr. Oz.....you can establish a ROUGH estimate of your BMR by multiplying your weight by 8 and adding 200. This would give you a theoretical number for daily calorie intake to maintain a given weight. Seems pretty crude to me and does not take age into account. For someone who is 150 lbs, a daily calorie intake of approx. 1400 would maintain that weight if you did no physical exercise at all. All theoretical of course.
ROUGH is right. What use is a rough guess, anyway? It's only worth anything as an initial approximation, when the intent for refinement is present.
A lot of the problem here seems to be confusion over BMR, RMR, and total daily caloric expenditure.
Different tools will give you different numbers depending what they're calculating. Some let you put in lifestyle activity levels, and let you add daily exercise. You have to be careful not to overestimate, and to accurately describe your daily exercise. The calculation is only as accurate as the data you give it, and it's not that great to start with.
These equations all assume you're similar to the populations used in the studies they were derived from; if you do some more digging, you'll find population-specific equations for early-20's white males, young african-americans, and many others. Body composition is often not taken into account. Usually, it's just body mass, sex, and age (the last two are essentially used as body composition corrections). You are assumed to be average; like BMI, it works on a population level and is relatively easy to compute, but you're going to have plenty of people who don't fit the curve.
What's wrong with examining your own diet and lifestyle, and tying those to your fluctuations in weight? It's as good of a guess as you're going to get (short of enrolling in a study or paying for it), and you'll get some insight into what changes can be made. It's a lot like estimating max HR to me: it's just a guess, so why not measure it yourself? It might take a little time and be too introspective for some, but it's worth more than a regression equation.