Can you tell me how much weight will you lose if all you eat if fruit?

That depends: I agree w dr. Wright. It depends on how much fruit you eat and how many calories that fruit contains. An all fruit diet is likely to be fairly high in sugar. It you were going to try this "short- term" would encourage you to eat more vegetables then fruit. Please remember that if you eat too little that your metabolic rate will drop & you could actually lose weight.