Hm, kinda sorta. The normal calculation is that 1lb of body fat stores about 3500 calories so if your weight is stable given your current diet and activity level and you want to lose 1lb you need to generate a 3500 calorie deficit.
You can do this by cutting down how much you eat - that is, taking in 500 calories less per day would save you 3500 calories in a week, thus 1lb. But the final caloric intake depends on where you’re starting from - going to some level (say 1200 calories per day) might be reasonable (at least in the short term) for a small woman who was eating 1700 per day but for a big guy who was eating 3000 per day it’s a much more drastic change.
I think that most people can certainly make some significant changes in how many calories they are eating by eating healthier foods (a cookie and an apple might have the same amount of calories but not many people can eat 20 apples whereas I know I can polish off a line of Chips Ahoy in no time), it’s definitely a critical part of staying healthy.
However in the long term I think you really need to have the right mix of diet and exercise - rather than just “eating less” to get thin (which makes me think of starving oneself) it makes more sense to add in exercise which burns more calories and has plenty of benefits aside from simple weight loss.
For example if I really wanted to lose 2lbs per week I’d much rather cut about 500 calories per day out by eating smarter and get an extra 500 calories per day of exercise in (depending on what you do that’s probably 30-60 minutes of exercise per day). There’s only so much you can “not eat”.