How much weight can you loose if you eat fruit 2 meals a day and a balanced dinner?

None fruit doesn't help your metabolism and starving yourself doesn't work in the long run. Temporarily you'll get 1 pound per 4,000 calories you cut, but again this is starvation, it is impossible to continue and survive, and your body will strike you with extreme hunger before you reach serious danger. Try whole grain foods, fish and nuts for your metabolism. Other foods including fruit are important for other nutrients in a balanced diet. Don't focus on one food group.