Can the sugar in fruit cause weight gain like other sugars? should i limit my servings of fruit if i'm trying to lose weight?

Yes and yes: Yes, fruit contains sugar, mostly in the form of fructose which can definitely cause weight gain. You esp. Want to limit servings of high-glycemic fruits which tend to be tropical fruits like bananas, mango & watermelon. The healthiest fruits are small fruits whose skin is eaten like berries, cherries, grapes, apples & apricots. You can eat those in moderation. Avoid fruit juices.