Troy finds it very hard to lose weight. no matter how often he exercises, he keeps gaining weight instead of losing it. he thinks that he has a genetic predisposition to be overweight, which has most likely made him sensitive to the hunger-promoting effects of?

 Ghrelin

Explanation: Ghrelin is the hormone found in the body that acts as hunger hormone .The functioning of this hormones is based impact of  consumption of food, growth hormones, fat percentage etc. It gets produced  and released  through stomach .

This hormone is also responsible for breaking down the deposited fat in the body and produce muscles.

According to the case ,Troy is also facing the obstruction from effects of ghrelin as he is not able to lose fat even after exercising which makes him thinks its due to genetic reason..

your the best there ever was you great your awesome your even better at your full potential you can accomplish this go fly like a free butter fly