I do Bright Line Eating (no flour and no sugar) and have lost 62 lbs from it (in 7 months) so far. The less processed and more natural foods you can eat, the better.
Walking is one of the best exercises you can do, in my opinion, because you can do it anywhere and anytime. If it's too hot, walk the mall. If you can get up early and beat the heat, there's usually a nice park or a waterfront place to walk at.
I agree with
@Robin about not being afraid of weights, but use weight machines and free weights versus a Body Pump class. I wrenched my shoulder blade in Body Pump class and had intense shoulder spasms for 6 weeks after that. If you've done something like Body Pump for years, you're probably good to go. I had not; took about a decade of a break from it. Some instructors don't teach proper form, etc., and they don't go around spotting people. Taking advantage of some free or reduced personal training, if available, might be a good option.
Hope this helps!