The author joined a men's weight-loss group and decided to set
a very different goal from the official one.
He had just read a book on weight loss that recommended clamping
The book says to simply not eat if you don't have a 'good appetite' when the
rest of the family sits down. Have a cup of tea...
down on his habits
until
"
growlies" appeared.
He recognized
This also resembles the way a control system with a thermostat behaves.
No growlies; don't stoke the furnace.
its strategy as
biofeedback
and wanted to see what his body
Possibilities:
The body could gently lower its BMI or
drop too fast (0vershoot) and
bounce back up.
would naturally do if he changed his
habits suddenly.
Measuring
The gentle drop possiblity would allow a spreadsheet to
measure this characteristic parameter of biological control.
Time Constant
He plotted the graph
to the right and tinkered with the Rate parameter
until the green line went sideways.
Spreadsheets have a "slope" function, which gave the rate measurement above
(also called a Time Constant measurement).
Sure enough, it turned out to be four seasons.
Looking for
The overshoot possibility was also a candidate, because the majority of
people who 'diet' will meet their goal and then their weight will
rebound strongly.Yo-Yos

Secondly, he wanted to see if
Overshoot in a control system usually is caused by a too-fast
response of something in a closed signal path.
"yo-yo" dieting
In yo-yo dieting, it seems to be will-power that is
both strong and short-term.
was caused
by "
ringing"
in the Step Response that one gets from suddenly producing growlies.
The answer was very clear - the curve was very smooth for the first few months
and it followed the Standard Decay Curve (decaying exponential) very well.
Furthermore, the other men were running into their own "yo-yos" and
were not doing as well overall.
The fact that using growlies is a
BioFeedback method;
(with no
In the previous link,
BioFeedback reveals something to a wired-up patient.
In our case the signal is just scale weight plus filtering.
instrumentation)
suggested that the Green Line for slope measurement could also provide feedback.
Just multiply slope by the measured Time Constant, one year, and try to hold it
on your goal.

That gives a horizontal line, which is what the app feeds back to you.
Responding to one number seems a lot less tricky than responding to growlies.
What remained was to add a layer of
strong filtering
to remove
To focus on jitter hides real but slow progress.
It is discouraging when daily fluctuations
give and then destroy false hopes.
scale fluctuations
and
Trusting the projection lets your willpower
recover while you coast a while.
That reduces the tendency to diet and collapse afterward.
give a reliable
one-year projection.
His Body's Horizontal Line Became DeeJay's Target.
That sent 40 lb down the river and, over a decade later, it has not come back.
Footnotes:
- See Wikipedia on Set Point Theories,
which says they have largely been
discredited.
There is good reason - too fast losses. This method avoids "set points".
- Mitochondria:
It is not yet known how to manage mitochondria for weight loss, so our best bet is to do it gradually and let them adapt naturally.
- More detail:
calculating projections.
Testing with
artificial data:
- Mayo Clinic seems to advocate a brute force approach to plateaus.
They are far from alone in that - protocols seem to miss dealing with the body's
characteristic time constant after "set point theories" failed to prove out.