I can't help with the food side of things (I'm lucky to have pretty much always been slim), other than to give general guidance on how I eat:
I try to ensure I have at least 5 fruit and veg every day (making them part of the meal rather than additional snacks IYSWIM? - so berries with muesli and greek yoghurt for breakfast, lost of veg with dinner), if I've eaten a large lunch say, I'll skip dinner (or just have some fruit and a little bit of cheese and crakers). I don't tend to eat much bread or pasta - I find they make me bloated and feel sluggish. I don't eat as much as my DH - I portion our meals accordingly. But I do eat cakes, chocolates etc, I've got a terrible sweet tooth.
However, exercise is something different. I used to be a complete exercise avoider, reluctantly doing the odd bit here and there because I "should". I've completely changed how I think, and now feel a bit angsty if I've not done something for a couple of days. The change in mindset took a REALLY long time (years I'm afraid). I think it started as I was approaching 40, was a little wobblier than I liked and had a double chin (despite being slim), DH had broken his leg so was stuck at home, giving me a lot of free childcare. I started seeing a personal trainer, and the rest is history.
I still see my PT now (4 years later), roughly fortnightly, and I do a variety of things at home in between - generally circuits type stuff with weights, some HIIT. I also try to get to a yoga class weekly, and do a circuits class, oh and while the evenings are so light, I try to get a minimum 30 min walk in after dinner with DH and kids.
I definitely think there is something for everyone, and if you enjoy it, it won't feel prescribed as such. I did Zumba for a while, that was lots of fun, but one class in particular used to leave me really sweaty, so was definitely doing good. I don't think I've met anyone who doesn't like doing weights once they've learnt how, and the results are quick and very measurable.
Activity watches have also definitely increased my interest - I'm secretly very competitive (generally against myself). I started with a Fitbit, but now have an Apple Watch that sets me daily and monthly challenges, plus I'm friends with other Apple Watch users, and we can comment on how we're all doing (tends to be abuse really
. I also set myself separate goals using the functionailty of the watch (eg this month I've decided to try to burn 10,000 calories during my workouts alone - all data from my watch).
Good luck!