Earlier quoted context omitted.
I actually WANT to go to the office, especially when it's nice out. My body is craving the walking and the activity, and the positive stress of being in a different environment is actually helping my mood significantly. I've become puffy, lazy, and slow. But not 5 days a week, no.
I've never understood this. If you work from home you can also just... go walking outside? In fact you could even go walking for longer, since nobody is checking for your presence and you haven't wasted time commuting. I'd rather walk to the lake and go for a swim during the afternoon, than walk to a train to walk to an office.
This requires some degree of motivation. When you had to go to the office you were forced to get dressed, get outside and travel etc. When you are WFH it is so tempting to get up late, get online, and stay comfortable. This is true even when you know what you are doing is unhealthy. It's similar to people eating a poor diet. They know they're doing it, they know it's bad, but it's hard to do the right thing (even when the right thing is relatively easy to do).
I say this as someone who loves WFH but also has fallen into a lot of bad habits that have definitely impacted my physical/mental health.