Will I lose weight if I eat the amount of calories I need a day but not eat fat foods Watch
Your weight will change in response to how you eat and how much energy your body uses. Eat more than you burn, you'll gain. Eat less then you lose. Find a balance and your weight will maintain. The reason many people end up yo-yo dieting is because they lose weight on a diet but then resume their old eating habits so all the weight returns.
If you want to lose weight, make small changes to decrease calorie intake (don't starve yourself) and increase activity (go for walks/runs, do workouts at home). Depending on your current weight, aim to lose a pound a week (slightly more if you're overweight, and if you're not that heavy then loss rate may be slower). When you've reached a weight you're happy with, add an extra couple of hundred calories a day and you should be at maintenance levels.
You can always gain back weight you've lost just as you can lose weight you've gained so you need to make lifestyle changes rather than use temporary measures
To lose weight you'll need to be in a calorie deficit.