There is no reason to get weak or hungry if you are eating enough foods and feeding your body.
Put all your information into the Start page to configure your calorie range in the Nutrition Tracker. Try to stay within the ranges for calories, carbs, proteins and fats - this should help to keep you from ever being hungry.
As you increase exercising you will need to increase calories a bit too. This is a learning process. But I know you can do this! We are all making this happen with SparkPeople!
If you eat 2000 calories a day (more than any diet) you would still lose weight but at a slower rate. If you are hungry, consider doing this until you can learn to add fruits and vegetables.