How long has it been since you've lost any weight ? If it's only been a couple of weeks, I wouldn't worry. While a safe weekly weight loss would be 1-2 pounds per week, there may be weeks you don't lose. there may even be weeks you gain ! And that doesn't mean you're doing something wrong. Depending on how long it has been since you lost any weight, you may just need to be patient. Now, if it has been longer than a month, then you may have reached a plateau. A plateau is not a bad thing. They are part of the weight loss process. The body doesn't keep losing week after week after week. At some point, your loss may slow down so that your body can adapt to the new change in weight.
Have you read any of the spark articles on plateaus ? If not, you might start with this one. www.sparkpeople.com/resource/fitness_artic
If you've been eating the same foods day after day after day or doing the same exercise routine day after day, then it's time for a change. the human body thrives on variety. So, if you've been eating the same foods, try some new recipes. If you've been doing the same exercise DVDs, try something different.
Also, did your doctor say it was okay to do any strength training ? If you're not doing any strength training and your doctor says it's okay to start, try adding one strength training workout per week. Strength training will help you to add lean muscle. Muscle burns fat and the more lean muscle you carry, the more efficient your body will be at burning fat. don't be afraid to strength train, you don't even have to lift weight per se. You could use resistance bands. Coach Nicole has a bunch of short 10-15 minute strength workout you could do at home.
But once again, check with your doctor and see if it's okay to do some strength training.
Mostly, you might just need to be patient with yourself and your body. As the Coaches all say,"trust the process". Even though the scale isn't moving, you're making changes the scale can't show. How's your blood pressure ? Do you know that if your blood pressure has dropped in the last month, your doctor would be thrilled even if the scale didn't budge. Lowering your blood pressure is a huge sign of success. So, don't assume you're not making a difference to your health because the scale isn't budging.
Are you losing inches ? Can you walk up stairs without getting winded ? Are you sleeping better ? Do you have a bit more energy ? can you lift more bags of groceries ? do your clothes fit a bit better ? The scale is only one way to measure success. When the scale isn't moving, look for other signs of change that maybe you didn't notice.