Fat utilization is associated with hunger. Hormones also control our hunger and satiety feelings. Thus, the second critical hormone associated with fat loss is leptin. To understand the role of leptin, we also need to know its protagonist hormone, ghrelin. These two hormones are chemical messengers running the metabolic show in our body. These hormones are like “yin-yang”. They work together. It means that while ghrelin increases hunger, leptin lowers it. So, when one hormone is active the other one gets passive.