I have been quite sedentary for several years, since going fully remote.

I had seasons where I would gain wait and lose weight, and my level of activity remained unchanged.

A few years ago, I started paying more attention to my weight, and got to where I was consistently in my ideal weight range. Again, level of activity remained unchanged.

About a year ago, I started indoor cycling (Zwift) quite regularly — about 2.5 hours per week, averaging right in the middle of my target heart rate zone. Diet remained the same. Weight remained mostly unchanged (still in my ideal weight range — I’ve maybe lost 5 or so pounds, but I lost way more weight when only changing my diet).

So — for me — diet has definitely had more impact on my weight than my level of activity.