To be honest, @labradorsandgin, I assumed you were on the wind up with that comment, which is why I ignored it. It was so facile, self-congratulatory and tone deaf in the context, that I didn't see how it could have any other purpose. You always get those remarks in weight loss conversations.
If weight loss and maintenance were so easy, we wouldn't have an obesity problem and a massive, multi-zillion pound weight loss industry. And most people who want to lose weight don't have the stress and exhaustion, not to mention physical recovery, of a new baby and recent labour.
I've lost a lot of weight, maintained it and lost my baby weight, so I know how it's done and I know it isn't complicated. But that doesn't mean it's easy, or there would be no overweight people. And actually it can be complicated if what is required is a total overhaul of the way you cook and prepare food.
Agree with PPs that exercise is important. It's just that you can't run off a bad diet. But I find I naturally make healthier choices when I'm exercising as it's so good for my mental state, which is where weight loss really happens.