Comment by josefrichter

I wrote biologically and mentally as first two points, these concern your body.

With diet you need to find what to eat, how much, how often, so that you’re not hungry, grumpy, tired, sick, etc. and still consistently lose weight. It’s gonna take a couple of weeks for your body to adjust.

Exercise will also drastically affect your hunger, tiredness, etc. It’s gonna be harder to find new balance (or rather dysbalance with consistent weight loss) when you can’t really read which changes in your body are caused by diet and which by exercise. Higher chance of disappointment and quitting.

I’d say just change diet, find what works for you consistently, add exercise only a few weeks later, tweak diet accordingly.