Hi bbielk,
Thanks for writing and welcome to the alli fitness forum. It sounds like you're trying very hard by eating right and exercising to meet your weight loss goals. I cannot tell you exactly what is going on, but I can give you a few pointers and suggestions.
Firstly, I would ask you how many times per week that you're exercising? To lose weight, it is recommended that you workout on most days of the week, meaning 5-6 days per week. Additionally, it is really important that you're getting your heart rate up to about 75%+, an intensity that will promote and maximize caloric expenditure and fat-burning. The alli website provides a place to calculate your THR (target heart rate). You should do your best to stay in that THR for 30+ minutes. If you are at a fitness level where that isn't not doable, go for as long as you can, even if it is only for a few minutes, and then recover and do it again! Anytime that you increase the intensity of your workout by increasing the elevation, speed or resistance, you will burn more calories per session than at a slow, steady pace. Try adding hills into your walks, 2-3 minutes of jogging/running, skipping rope between exercises, jumping on a mini-tramp for a couple of minutes, or increasing your weights 5% every couple of weeks. Adding intervals of higher intensity exercises will really jump start your metabolism and take your workout to a whole new level.
That said, I would really encourage you to include a variety of different workouts. Since you mentioned that you've been going to Curves for quite some time, it may be time to change up your routine. Join a local Boot Camp! These are very, very effective in burning significant calories and taking your body into different energy systems by incorporating cardio bursts, strengthening/toning exercises, plymetrics and core/balance work. Try a Spin class, go hiking, biking, try a new & fun video like Yoga Booty Ballet, and for sure begin a regular, strength training program. Ideally, aside from cardio, you should be getting in 2-3 full-body workouts of strength training per week, each session lasting 25-35 minutes. The alli website provides helpful, animated demos for a very effective full-body workout and gives you information re: reps, sets, etc. All you need (if you don't belong to a gym) is a FitBall, exercise bands and dumbbells and you're set!
Lastly, if you find that none of the above works and you've been very faithful and consistent for several months, there can be other physiological factors that cause weight loss resistance. Adrenal fatigue, thyroid issues, hormonal imbalance and insulin resistance can all reap havok on your weight and over-all well-being. You can go to your family doctor and have these conditions explained to you at length, and a simple blood or saliva test can let you know if you're dealing with any of these issues!
Keep up the great work, stay positive and keep me posted with your progress!
Yours in health,
Kelli