There's a really good video on this - https://www.youtube.com/watch?v=vSSkDos2hzo
Adding a little exercise to your life is rarely a bad thing, but to shift fat diet change is the big one.
Here's one that will have a steady impact - drink an extra glass of water with each meal (helps you feel full for longer), and invest in an apple corer (for easy apple snacks) - aim for an apple a day. It's helping me slowly lose body fat by reducing caloric intake.
Nuclear isn't the worst option if it pushes us to net 0 fast, especially if investment is made in spent fuel processing facilities (government owned).
It is very much a stopgap, but at this point some kind is likely needed.