Hormones send signals frequently to your metabolism , one commonly known hormone associated with weight is Leptin, which is what sends signals to your brain letting you know that you are full. However, if you eat too much fat that could create excess Leptin, the brain will become resistant to this hormone that signals you to eat which will cause you to eat more and gain more weight after you begin to lose the sensation of being full.
And as a first mention can affect your metabolism, but another major hormone that affects this is cortisol which helps regulate the metabolism and manage stress , if there’s too much stress on the body it could caused an increased appetite as well as increased fat on the abdomen (stomach.)
In addition to these hormones, thyroid hormones also regulate the metabolism. When the hormones in the thyroid gland are too much or too little it can result in extreme weight gain or weight loss as seen in patients with either hypothyroidism or hyperthyroidism.