Some of the information on here is very misleading.
A healthy diet can absolutely contain sugar, unless there is a reason you have been told to control intake of it due to diabetes etc. And also fat. Neither of these is ‘responsible’ for obesity in the correct amounts.
Over processed foods tend to be much less healthy than less processed foods. So a diet high in vegetables, fruits, wholegrains, plant protein, eggs, Greek yogurt, olive oil, fish etc is very healthy (if your overall lifestyle is healthy and you’re not hugely over consuming things). One that is full of cereal bars, protein shakes, smoothies, processed cereal is not.
It’s absolutely fine to eat a little bit of chocolate, have a packet of crisps every now and again, or have a smoothie when you fancy one.
Variety, moderation and common sense and trying to enjoy both food and exercise (and life) are key to a healthy life. And mostly consistency- veg at every meal, daily exercise of some sort.
I think the confusion often comes when people have got very overweight in the first place and have a really unhappy relationship with food, and are looking for some epiphany about what to do, whereas actually the reality is really boring.