I'm going to copypasta something I posted the other day with regards to this. But as you've found out, it's not what you eat but how much you eat. If you overeat nothing but veggies(kind of impossible, but go along with it) then you'll gain weight. If you eat at a deficit nothing but whoppers and fries, you'll lose weight.
So while it's not and still not complete, I hope the information below will provide some insight on what's needed for weight management.
Any "diet" works for fat weight so long as you're in a caloric deficit. The problem is that it takes a while for fat to actually be burned. So if you're weighing yourself 1-3 days after starting any diet of course it's likely you haven't burned much fat. It's generally recommended that when you weigh yourself give it 1-2 weeks.
Also, water weight tends to go pretty fast and unless you eat all of the wrong stuff the wrong way on a cheat day it'll stabilize after that first week or two.
I'm going to try to keep it short, but if you'd like a more detailed explanation of all of this I don't mind giving it.
Losing weight is simply calories in vs calories out. If you are consuming less calories than your body needs you will lose weight. You could, although I don't recommend it, eat nothing but fast food for every meal and still lose considerable weight. And I'm not talking about their crap salads either. I mean getting a big mac for every meal. So long as your calories in is less than your needs, you will lose weight.
There's tons of calculators to figure out your caloric needs. All of them are estimates and may take 1-3 weeks of playing around to figure out your maintenance calories, or the calories you need to remain a stable weight. Simply put, this is determined by your basal metabolic rate, which is based off of your age; weight; height; and sex, and your activity level which not only includes your exercise regimen but all activity you do in the day.
After that, you subtract calories to go into a deficit to lose weight or add for a surplus to gain weight. Now, it's silly to just say "Hey, gonna subtract 1000 calories." Generally speaking, you shouldn't subtract or add no more than 20% of your maintenance. Weight loss and gain is a slow process.
So you figured out your calories? Well, really, that's all you need. Now here are some skills you'll need to learn, how to read nutrition labels and how to measure food properly.
When you learn how to read nutrition labels and then how to count calories, you'll notice the serving size. Do not try to eye ball it. Most of us completely and totally overestimate the serving sizes, especially with our carbs like rice and pasta. Get measuring cups and spoons and measure. Yes, it is a pain, but don't cheat yourself.
You need to count everything you put in your mouth that isn't water. I'd recommend some kind of journal, on or offline, to keep track. Do not cheat yourself on this. If you ate that piece of chocolate, write it down. You're only doing yourself a disservice by cheating and not writing down.
Eating clean is cool, but it's hard. Really hard. Don't deprive yourself of things you love because they're "unhealthy". You'll hurt yourself so bad psychologically that you'll be prone to binging, and then beating yourself up over it. Now that you know how to count calories you can adjust your day around that ice cream if need be.
Try to avoid eating out. The nutrition information restaurants give isn't often accurate because of human error from those serving you food. You'll do much better measuring out and cooking your own food almost 90% of the time. If you have to eat out, go ahead and add an extra 300-500, and sometimes I dare say 1000 calories to what you're really getting. Like seriously, when I get ice cream I tend to get a bit extra depending on what girl is behind the counter that day.
Drink water, lots of water.
7-8 hours of sleep otherwise your body is pumping all of that cortisol in you which may inhibit your progress.