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 down on 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... 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 would Possibilities:

The body could gently lower its BMI or

drop too fast (0vershoot) and bounce back up.

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 (also called a Time Constant) until the green line Spreadsheets have a "slope" function, which gives the rate measurement when the line goes sideways. went sideways. 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.

The fact that using growlies is a BioFeedback method; (with no Usually, 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. 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.

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Footnotes:

1. 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".


2. Mitochondria:
   • are the power-house of cells.
   • are implicated in insulin resistance, and diet affects the process.
   • play a central role in recycling of body cells.
   • cause "brown fat", which is known to produce body heat.
   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.


3. More detail: calculating projections.
   Testing with artificial data:
   See also feedback control for an in-depth description of this process.


4. 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.