You've tried a change in food? What types of food did you change from, and what types of food did you change to? Are you watching portion sizes? Have you been tested for medical conditions that might prevent weight loss?
What have you tried, so far? Typically, cutting calories or changing the types of food we eat and getting a moderate amount of exercise is sufficient to lose weight, unless there's a a medical condition that's preventing you from doing so, such as hypothyroidism, insulin resistance, etc.