Do you resist turning your central heating on until November and make sure that it is off by April and grit your teeth through a few chilly days either side? (Assuming that you're in the UK or the northern hemisphere at least...)
Do you keep your central heating set to 19°C or below, and if you have TRVs do you keep them set to half-way or below?
If so then well done; you are almost certainly saving yourself significant money and helping to keep your weight down too! (Can you ever be too slim or too rich in pop culture?)
Basically the suggestion is that if you don't let your body experience the cold of winter it doesn't get the right cues to adjust metabolism and, for example, your 'brown fat' cells don't burn off excess calories as they should.
Running around your home in underwear mid-winter has never been a good choice from a money (or fashion) point of view, and seems not to be healthy for you or the planet either!
One person said "Heating on most of the year - that's what thermostats are for, surely?"
I've noticed that in spring I'm prepared to put up with slightly lower temperatures (while keeping the heating off entirely) than I am in gloomy mid-winter. We're not consistent thermometers so sometimes push yourself a bit harder to save a few more pounds in the bank and off the waist?
(Radbot tip for April/October.)