Best exercise to start with?

Just use the search function for the site on "best exercise" and you will find literally a thousand threads with this exact question .

Walking is usually recommended because it's a good calorie burning workout, it requires no special training or equipment, and it is typically not hard to find a place to walk.

Running requires running shoes (not cheap Walmart ones), is harder on joints and muscles, and is more challenging generally. Not that you can't start out running, though.

That being said, what else?

I suggest thinking about what you enjoyed doing as a kid...on the playground, with your friends, with your family, at summer camp...whatever. There's usually something you enjoyed then you may now.

Walking is easy and works well. If you really want to get into running look into the Couch to 5K programs. Swimming is also great and easy on the joints if you have access to a pool.

What are your interests? I'd start with that. So many people just do things they don't necessarily like doing just because they read that they should be doing it in some fitness magazine...

I personally started out just walking but that was just because my fitness was so low, it was about the only thing I could do...I just focused on moving more in general and getting out for some deliberate walks. I went from that to doing a C25K and though I loathed running, I kept at it for months...I was pretty miserable, but I thought that's what I had to do to be fit. In training for a sprint triathlon many months later I discovered a passion for cycling...I've been riding ever since...few years now.

Whatever you end up doing, try making walking a part of it. Changing your mindset and habits around walking will pay dividends now and when you are in maintenance. Even a couple hundred calorie increase in TDEE done persistently adds up over weeks, months, and years. I'm not a rockstar with my steps, but they are slowly increasing

I've always been a walker. Partly because I'm unathletic and uncoordinated. (As a kid, I was diagnosed with gross-motor/fine-motor issues. Mostly today it translates into 'no good at sports' and 'going by my handwriting, I should be a doctor, but I haven't enough aptitude in science').

I use a fitness glider (Gazelle Edge) which is primarily a cardio machine, but also helps work the upper body muscles.

And, after lurking on these boards a bit and seeing people talk about how strength training helps to strengthen and preserve muscle that might otherwise be lost in a calorie deficit, I walked into a fitness store and asked for advice. They suggested either fitness tubes or weights. I went with the tubes because, pragmatically speaking, the store was forty-five minutes walk from my house and I wasn't sure if I could comfortably carry the weights home (and what if the shopping bag tore?).