Weight Change Calculator

We will develop a wiki based calculator that will be useful for Projecting Weight Loss after a step-change in caloric balance. We hope to improve the utility of a bathroom scale while offering insight and encouragement to those who aspire to eat differently.

Our strategy is to capture data measurements while there is still enthusiasm for a change in habit. Then, with interactive modeling of the changing rate of change, we will produce encouraging numbers that respond appropriately to small fluctuations.

We are currently using a spreadsheet model. With each new measurement we perform three steps that we would prefer to see done here.

Record the data to 0.2 pound resolution.

Adjust the presumed Asymptotic Weight to achieve the straightest possible curve plotting Loss Today on a logarithmic scale.

Adjust the model's presumed Daily Rate of Loss to match the slope of the Loss Today line on the same scale.

We simultaneously project the observed data and a model based forecast on a linear scale. Here one sees an exponential decay to a horizontal asymptote.

Our approach to fitting worked great with three samples. As we approach a week we see that we have to weight or even ignore some data. The respective validity of both the least-squares and three-point methods becomes obvious.

Time passes. Now at three weeks our curve fit is stable. What ever we've been losing we've been losing at a consistent exponential rate of 10% per day. Our personal disappointment is that the indicated asymptotic weight is not were we wanted to be.

Modeling transitions in body composition: the approach to steady state ... starvation study. Excel. nih.gov

Computational model of in vivo human energy metabolism during semi-starvation and re-feeding nih.gov

Jean-Pierre Flatt, Professor Emeritus, UMass. pubs

Explore fitting to an exponential decay with non-zero asymptote. google