Thursday, 18 April 2013

Taking a look at weight data

Warning: This might well be the most boring blog post I've written so far (and that's some claim). It's immensely interesting for me, and probably not for anyone else on the planet. You have been warned...

So, I finally gave in to this damn cold. I've struggled through this week at work with an annoying cold (sore throat, blocked nose, main-lining Lemsip) but enough is enough. I'm sitting at home on the sofa today, catching up on the wonderful Talk Ultra (twitter) podcast by Ian Corless. Thinking about weight in my last post, I wanted to take a closer look at the last few years.

Firstly, I'm not weight-obsessed, and I've never had a weight-related illness (in case you're concerned I'm dwelling on the topic in an unhealthy manner). I am however far more informed and observant than I have ever been previously in my life. Part of this is thanks to Mrs who successfully lost a lot of weight earlier in her life and has kept it off - it'll be 7 years in May, she's done an amazing job. She was far more tuned in to food, weight, and general health and general wellbeing than I was.

I thought a useful past time this morning was to sit for a while and see if I could see where the major directional changes were, and why.

On 78.4% of the last 1,650 days I've weighed myself first thing in the morning - 1,294 data points

The orange line is logged data (and it's always been from the same pair of scales), and the black lines are interpolated. If I was away for a weekend and measured 90.0kg on Friday, and then 90.3kg on Monday, I'd add in 90.1kg and 90.2kg for Saturday and Sunday. I never tried to weigh myself on anything other than my home bathroom scales. If they're poorly calibrated, I'll at least assume they are consistently offset each day.

When Mrs swapped from her old analogue scales to my digital ones, she had a discontinuity due to differences in calibration.

A fake 5kg discontinuity due to a change of scales

The overall trend over the 54 months is downward, but there are some serious ups in there too! The following graphs span 12 months on the X-axis and 15kg on the Y-axis. This means the angle of the trend line (the rate at which my weight was changing) can be compared from year to year.

2008: The first time I'd ever weighed myself twice in the same year

Only a couple of months of data for 2008. The thing I can't believe is that I started at virtually 100kg (15st 10.5lb) - and I'd been heavier in the past, during my fairly unhappy days in Scotland. At this point I was taking a lead from Mrs, all about low fa and calorie restrictions. It worked well - I was clearly ready to ditch the pizza and shed a few pounds. This period from October to December is one of the most rapid weight loss periods in the whole 5 years.

2009: Can you spot my honeymoon?

I got married in April we spent a few weeks in California on honeymoon - that added a few kg! The second half of the year shows a gradual and sustained decline (Right! We're married! Let's not get old and fat!) - with one or two exceptions. At the start of November I went to a work conference in the US and came back a week later and 4kg heavier! It falls off quickly, but it's worth noting that sudden increases never come decrease at the same rate.

2010: The only way is up!

Looking at the years in isolation, 2010 is the "worst" (making the bold assumption that a downward trend is "best" and is desired). There was a lot of being out and boozing during this period - my team at work was expanding rapidly, and "team building" was very high on the agenda.

2011: A year of triathlon

We raced quite a lot in 2011, but not with any serious or structured training. At the end of the year, start of November, we went on holiday. That was bound to cost a few kg! Trend was down over the period. What's interesting is that almost never is there a period without a gradual trend up or down - not just in this year but in any year. I'd think it would be fascinating to see a graph of my weight since I was born.

2012: Year of the Ironman Ultimate Challenge and going LCHF

This is one of the most interesting years. I came into 2012 with my first ever triathlon coach, and an objective to compete in Ironman 70.3 UK and Ironman Wales. My training was the most consistent it's ever been in my life (it's actually the only year I've ever done anything that would count as structured training).

Jan to June were perfect. I was getting leaner, faster, stronger. I hardly drank any alcohol during this period. I believed alcohol was a main inhibitor to previous weight management, and it would affect my training. The odd effect though, was that as soon as my big races started towards the end of June, I steadily gained weight all summer and throughout all the other races. In retrospect the focus and limitations I'd put myself under for the first part of the year were simply unsustainable. I hadn't got the right balance. I also had a blow-out after each big race, and never quite recovered afterwards. You can see this by the upward spike in black (interpolated data from while I was away racing), followed by an immediate not-quite-recover in orange when I got back home. I'm pretty sure I still don't know what my "racing weight" is, I don't think I've ever reached it!

The end of the year, starting about a third into November, was when I went Low Carb High Fat (LCHF). My weight fell off a cliff. December is the longest sustained period I've spent under 80kg - 25 days. The trend breaks at Christmas with a spike back to 80kg - yesterdays graph map that directly with my carb intake increasing above my target max of 50g/day.

2013: When LCHF becomes HCHF!

An example of how not to do it! Note the downturn in the last few days as a result of changes made since Saturday. Let's see where this curve goes...

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