Captain's Table

Mark Austen

2021.05.11 - Back on the Diet, the Progress

So how is this going? Well, to answer that I have first to tell you that I trained as an engineer many years ago and as a result I measure things with graphs and statistics. These days you can download a free spreadsheet that will allow you to plot lines of linear regression over a data set and I do use these to see how I'm doing. Here's an example:

This is my progress from the beginning of the year to date, and as you can see it is pretty stable up until a sudden weight increase around 4th April when we visited a friend for lunch and I made some bread. I also ate quite a lot of it and you can see the result. It takes about two weeks to recover from that although it has to be said that I'm didn't try very hard as I could see that the weight is coming down albeit slowly. The sudden down slope at the end of the graph is when I went back on the diet properly and started to seriously lose weight. As you can see from the graph, I went up in weight for two days, not sure why and at that point I started the diet. The result is a steady decrease in weight.

This is a closer look at the last 28 days.

But, I have one problem with the spreadsheet, you can't see the data of the regression line shown in the top graph. I want to know the steepness of the slope as a number, not just as a line on the screen. Is that line going up or down? And by how much?

So, I get the spreadsheet to calculate it each day for me. Linear regression by least squares. Firstly over the entire year and secondly over the last two weeks or so. The slope for the year has a value of 0.234 g/day and for the last 12 days the value is -207 g/day. In other words, over the entire year the slope is nearly flat, just a very slight upward trend, whereas over the last 12 days I'm losing 207 g (7oz) every day on average. The first value is worthless, the second figure is of more interest.

Now why 12 days? That's because 14 days includes the two days when I put on weight and I'm not interested is those two days, only the days from when I started the diet. In two days time I'll set the calculations for the prior 14 days and leave it at that figure.

This is really boring stuff for most people, but I find it fascinating.

The answer to the question posed at the start of the post is; really well.

Time for a cup of tea and a sticky bun. Except we don't have any sticky buns and even if we did, I'm on a diet !