OP don't listen to the colleague, and frankly the nitpicking going on in this thread isn't too helpful either.
Strive for making changes you can maintain.
You know just by looking on a plate which meal, as a whole, is better. Trust that feeling.
You can get nitpicky once your relationship with food is better established and you're confident.
I ended up losing 3 stone over 3-4 years. It sounds like it took a long time, but that's because I wasn't dieting just changing my habits. I also started off being what I thought of as a bit overweight but nothing a doctor would call me out on. But I was struggling to keep weight off and often failing, even though I was technically in a caloric deficit. The funny thing is, calorie wise, I'm eating the same amount as I used to-- but what's changed is just replacing the old food for a ton of lower calorie veggies and doing the rest with moderation.
My first swap was to halve the breads/pastas I ate and replace the missing half with vegetables of similar caloric value. That means a half sandwich with a ton of veggies. I also started adding in leafy veg (spinach, watercress, rocket...) to my home cooked foods. Nobody notices that a bag of rocket snuck itself into the ricotta cheese and tomato sauce layers of lasagne. People act like it's an herb. I also at that point started buying all unsweetened products. It takes the tongue a while to adjust to the new flavours so don't rush it--but I did find it worked better to replace all unsweetened dairy at one time, because then you don't have say, strawberry flavour yogurt sitting beside unsweetened. Why tempt yourself?
The whole low fat/full fat thing is a bit overblown unless you're serious about counting fats as macros. If I were in your situation, I wouldn't bother. Get the habits down first then refine. Ideally don't worry about macros for a year or so after you've established healthy eating habits.
Salads have been a real saviour for me. If you need a bit more heft, you can add some whole grain like quinoa or bulgar wheat. Spring rolls can essentially be salads slapped into a rice wrapper, too, and so that varies it up a bit.
A good Green Goddess smoothie once in a while will make you feel like you've done something really praiseworthy. There are lots of recipes online. Basically mix a ton of green leafy veg with enough fruit (melons are great) to make it palatable then toss in some flavouring like ginger and parsley (I was sceptical about the parsley at first) and you need a lighter flavoured liquid. Cooled green/herbal tea or coconut water (but ouch that stuff is expensive) or maybe some watered down citrus juice. And viola! You've drunk a salad for breakfast. If you've got to add a teaspoon or two or three of sugar to make it palatable then that's not the worst thing ever. It's still superior to a croissant. ;-)
Focusing on if your current meal is better than your old one is crucial. It's progress! Cheer it on! You are doing fab so far.