I lost 40 pounds and kept them off by counting calories - measuring solid foods by weighing out the serving sizes that were specified on food packages or online, and measuring liquids the same way. Going low carb or cutting out a specific type of food doesn't work, and you dont need to pay for Weight Watchers. Just sign up for myfitnesspal, or google "how many calories does ot take to maintain my weight?" (maintaining the weight means staying at the same weight, not losing or gaining) and eat less than that and you will lose weight. Keep in mind that 3500 calories of food equal one pound of fat. Eat 3500 calories less than your maintenance calories and you'll lose a pound, just like eating 3500 more will cause you to gain a pound.
You might wonder how this should be calculated. You know your maintenance calories is the amount of calories it takes to stay at the same weight, but when it comes to eating 3500 less than that, you might not be sure whether you're supposed to be calculating this based on how many calories it takes to maintain your weight on a daily basis, or a weekly basis, or monthly, etc. Well, how you would do it all depends on how many or how few calories you need to consume per day, week or month to maintain your weight, and how fast you want to lose weight. For most people, unless they're absolutely huge or extremely active or something, it doesn't take more than 3500 calories a day to maintain their weight, therefore eating 3500 less than maintenance every day would be impossible and trying would be unhealthy. But if you are 200 pounds, for instance, need 2,000 calories to maintain your weight and wanted to lose a pound a week, you could eat 500 calories less than daily maintenance i.e 1500 calories, meaning you'd be eating 3500 calories less a week and would lose a pound that week.
Keep in mind that the amount of calories you would eat to maintain your weight will probably decrease as you lose weight and get smaller. Bigness of body, as well as being more active, are a few factors that usually increase your maintenance calories.
Keep a balance between healthy foods and treats, dont deprive yourself, and realize that if you've been doing this a few weeks and the scale isn't budging, then you aren't weighing / measuring or keeping track of how much you are eating (you MUST try to be as accurate as possible, solid foods should be weighed and not measured, and you should not ignore things you consume like butter, condiments, oil or small bites of things here and there, because everything you eat counts!), or that you only think you are not losing and theres a water fluctuation going on in your body, which can be caused by many factors.