Hi OP. I'm 5ft9, and slim (almost skinny), size 8-10 in clothes. The key IMO is not what you eat but HOW you eat.
I was a size 16 when I was in uni over 20 years ago and I absolutely hated it. I like food but preferred myself slim so I started intermittent fasting (like 5:2 diet). I figured if I ate much less one day, I could eat what I wanted the next.
I also started thinking about my actual body; about how our body processed what we feed it, does our body 'need' to be fed 3 times a day, everyday? Surely, you wouldn't water a plant if the soil was soggy, you wouldn't add more fuel to a tank if it was full.
The result of my eating pattern was that I physically became unable to eat as much on my normal eating days. Till now, if I eat a large meal, I'm simply unable to eat anything all day the next day except some pieces of fruit or nuts. Your body just changes the way it accepts food over time. At least my body did. I don't think I can do a traditional diet - I have to be able to eat everything!
When I was pregnant, I didn't 'eat for 2' either so my body didn't hold much fat after birth. I have saggy tummy skin but that's another thread!
I now naturally also use the 16:8 method (it's still intermittent fasting) where you only eat in an 8 hour window. You're asleep for most of the rest anyway. My window is around 12-8pm. I haven't eaten a proper breakfast in about 16 years. My body just isn't ready for proper food in the morning. Maybe a piece of fruit. I do my feeding from around noon.
I eat WHATEVER i like, but I can't physically eat large quantities of it.
Here's what i ate yesterday (not in order): rice with chicken, ice-cream, hot chocolate, lemonade, bread, nuts, grapes, dried fish, grapefruit juice, my daughter's discarded MCnuggets, a boiled egg with the rice. I always have lots of chocs, sweets, crisps, biscuits at home but I'm one of those that can't eat more than 3 biscuits in a day. I eat a sharing bag of Haribo or other sweets over 1 week.
Are you doing the 10000 steps a day? If you aren't maybe you could start that. Many people use a fitbit (other brands available) to monitor their steps.
Here's a home walking video that I still use when I feel I've been inactive during the day (or that I've eaten too much)