Swimming makes you fat?

Nah - surely not?
Ok, that was a bit of a reactionary title going on there. Swimming does not necessarily make you fat, it's exercise and it burns calories, however, my experience of it recently has meant that I lost muscle and gained, well... fat - noticeable in how I look and how my clothes fit.
How can this be?
Partially through my own lack of self control- let me explain.

If you follow this blog, or know anything about me, you know I'm mainly a runner. I'll happily go out for more than an hour without really thinking much of it, and batter up and down some hills around the Peak district, and tend to do that most weeks. As it is, I use a fair amount of energy, and try to make sure I put it back in, mainly in the form of significant amounts of food.

Since November I had been trying to improve my freestyle (Crawl) stroke and have been visiting the local pool at least 3 times a week. Each time I go, I practice technique, I swim a good number of lengths, normally more than 1km, sometimes up to 2km, and generally speaking I swim for a total of 20-40 mins, not including rest time. The effect of this has been that I have been absolutely knackered! I get back in from swimming and eat. I eat more during the day, and I'm so tired that I can barely make it out for a run.

It isn't like my legs are tired, but systemically- I was knackered.
The idea of overtraining of course rears its ugly head- but in order to get better at swimming I need to get in there and practice technique. It isn't about masses of miles, and I'm certainly not doing masses of miles... but it was the consistent training that over the winter months that really wore me down. I ate more and I ran less.
Even though I swam three times a week- it was only for 3x 40 mins. This is nothing in comparison to the amount of running I normally do, especially when you consider how many calories one expends swimming in comparison to running- but I was feeling so tired that I was probably eating much the same amount of food.

What helped (funnily enough) was that the coronavirus kicked off, so swimming in a pool is kind of off the cards right now. As a result, I have more energy. I run a whole lot more and, whaddaya know... my body shape is changing back to how it was prior to doing a load of swimming. My belt now does up on the "correct" hole, my t-shirts fit better, and I look different.

I'm hopeful that the last 5 months in the pool will help me be more efficient in my outdoor swimming endevours, I can hardly think that it has damaged my ability to swim. But crikey, it taught me that starting a new sport in earnest really makes you think about energy expenditure and energy choices.