Precisely so!

In preparing my personal chart used in my blog article, at www DietHobby.com
I brought up an online calculator for the Mifflin and the Harris Benedict formulas.
I input my own personal data; i.e. my own sex, age, and height.
The Weight column at the far left of the chart reflects total body weight
...using my own personal data...from 95 lbs through 165 lbs, topping off at 200 lbs.

The Mifflin RMR column and the Harris-Benedict BMR column are the
online calculator's numerical results based on that data.

For the Mifflin plus Activity number (Mifflin + Activity #) column,
I added the standard 1.2% activity factor for "sedentary".
Yes... that DOES cover ALL of the daily activity of a normal sedentary person
with MY PERSONAL DATA. i.e. My sex, age, and height at those specific weights.

For the column on the extreme right: MY Mifflin plus Activity number,
I subtracted a percentage of between 10-15% (150 calories) from the total "average person with my numbers" calculation.
which resulted in bringing me very close to the ACTUAL numbers
shown by my own personal detailed long-term daily food-intake computer records,
during the past 7 years while my body has been at a weight of between 110 and 130 pounds.

I consider myself to be a sedentary person, and have discovered
that ... FOR ME ... additional exercise does not result in much of an increased calorie burn.
Also, my long-term exeriments have proven that My body compensates
for additional exercise by making me very hungry, AND very tired.
I'm fairly good at resisting the extra food when I'm hungry,
however, I'm unable to resist resting when feeling extremely tired and/or sleepy.

I agree with those experts who believe that, for many reasons,
it is almost impossible to get accurate individual Exercise Calorie calculations.
However, to give you an example:
an online exercise calculation --for a person WITH MY PERSONAL DATA, --
20 minutes of walking at 3 mph would burn a total of about 60 calories.
NOTE: I am quite short so 3 mph is quite a brisk pace for me... almost a jog.

REMEMBER -- I am a short female in my late 60s....
AND... on top of that I'm a "reduced obese" person,
which Dr. Rudolph Leibel's research indicates has a lower exercise burn
than "normal" people.
For more info read the sticky topic above :"Some Answers About Genes etc...."

Interesting. I'm 56 and also quite sedentary aside from my 3-5 hours per week of formal exercise. In my case, however, it seems that the exercise makes a huge difference. I'm pretty certain that I wouldn't be able to maintain on anything close to 2,000-2,200 cals/day (my current range) without it. This is just an unscientific hunch, but I've always felt that I burn more calories than most people when exercising, because I don't have naturally good stamina and exercise is really WORK for me.

Freelance

I have just played around for a while with the calorie calculator at calculator.net. Very interesting. I've never done this kind of math before. The difference in estimated daily calorie needs (to maintain) between sedentary and moderately active (defined as exercise 3-5x/week) is 400 cal (1371 vs. 1771). Commensurately, to lose 1 pound per week, I would need to drop my calorie intake to 871 (!!!) if I remain sedentary, but "only" to 1271 if I exercise. Not coincidentally, I have found through trial and error that I lose weight on 1200 cal/day + 1 hour of exercise 4-5x per week. As you (Phyllis) point out, the trick is to not allow that hour of exercise to influence my eating, but to remain steadfast at 1200 cal/day regardless of activity, which is d*mn hard. But, at least for me, still easier than eating <900 cal. day for weeks at a stretch.

Oh, I also learned that there is another formula (Katch-McArdle) that takes into account your body fat%, which the Mifflin formula doesn't (and which presumably means that people with a lot of muscle mass for their weight can eat a bit more than the Mifflin formula would suggest), but, stupidly, loses the information about age and sex, which presumably adds a source of uncalculated variation into that one. Pity there isn't a version of Mifflin that works on lean body mass instead of total body weight, because I bet that would make the darn thing a lot more accurate.

Playing with the numbers is an interesting activity,
and I enjoy it. One important thing I keep in the front of my mind is
It's ALL based on an "AVERAGE" mythical person...
I find the numbers useful to see where the "average" is,
with the understanding that there can easily be a large difference in either direction.
Unfortuately, for me personally, the difference is LOWER, not higher.

The Katch-McArdle formula involving lean body mass is interesting,
but, as you discovered, presents problems.
Personally, I don't think the metabolism differences between people
would be resolved by using a "Lean Body Mass" formula,
and .. of course... acurately calculating that number "EXACTLY"
takes a lot more individual information and expertise
than merely stepping on a sacle.

I've been lurking around the maintainers section for a few months now and maintaining sounds so difficult! So I've decided to aim for losing about half my excess weight. If all goes well and I can maintain that weightloss for about half a year or more then I'll continue to lose weight.

That sounds like a good plan.

^ Thanks!

This is the thing that I failed to do the most the many times I had been successful in losing. Especially when the "creep" gets to be around the 5 lb. mark for me.

I am nowhere near goal and in fact haven't been making much effort to lose recently. That's going to change. But I needed to come to this section because of this little voice in my head that was going "Why bother at all - you'll just gain it all back?" Guess whose voice that was . . . Satan's! Not gonna listen to it!