Are you writing down everything you eat and counting up your calories for the day? The first step is knowing how much you eat in a day and about how many calories you burn per day. Then you can reduce the amount of calories you eat so that you are burning more calories than you consume. You need to burn 3,500 more calories than you consume to lose 1 pound, so eating 500 fewer calories than you burn per day results in a loss of about 1 pound per week. The next step is to start replacing unhealthy foods in your diet with ones that are better for you.
I started at about 150 pounds last September and have lost close to 30 pounds through exercise and limiting my calories to 1200-1400 per day (I started at 1200 and slowly worked my way up to 1400 by exercising more). I tried to lose weight without tracking everything I ate, just by eating healthier foods and exercising, and it didn't work. I did not lose weight until I started keeping track of everything I ate and planning my meals/snacks to stay within a specified calorie range.
My calorie range may not be right for you (I'm a little bit shorter, I started 10 pounds lighter, and your lifestyle may be more active or sedentary than mine). A couple of websites that can help you figure out how many calories you burn per day are www.fitday.com
. These aren't perfect so you may still need to tweak your calorie level, but they can get you started.
Another way to figure out your calorie level is to figure out how much you are eating now and reduce it by 100 calories per day for a week at a time until you are losing 1 to 2 pounds per week.
You also might want to browse the calorie counters forum on this website, there is lots of good information in there about this method of losing weight.
Once you get going, I think you'll find that it gets easier. You'll start to get a feel for how many calories are in the foods that you eat regularly, which makes planning a lot easier. You'll also get good at strategizing what you are going to eat and when, so that you aren't hungry throughout the day. You'll also figure out which foods give you the most bang for your calories--i.e., taste good and leave you feeling the fullest the longest with the fewest calories.