I once calculated the distance I had to walk (at a fast pace, with or without elevation change) to offset a single Frappuccino. It was a depressing but certainly doable number. Some fitness apps give you a vanity number of calories spent that don't subtract baseline metabolism though.

Agree with the observation that keto mostly helps increase satiation and therefore calorie intake. The one time I did that it was very effective, but not fun.

Exercise may, in addition to obviously burning calories, have some influence on (the type of) appetite too. I haven't read up on any studies.