Hello Jamie91,
When you look at the statistics for the food your eating make sure it is low in sugar, fat, and carbohydrates. Unfortunately the classic fresh food that is good in this way is veggies and fruits. You might just have to force them down (no extras or frying or anything like that). Also you should be exercising regularly. Diets are good but they usually arent enough. Regular exercise is key. Start off with a long walk and progess to more as you feel more confident.
I hope this was helpful