What hormonal imbalance could potentially lead to weight gain?

Low levels of leptin can lead to weight gain because leptin is a hormone produced by adipose (fat) tissue that plays a critical role in regulating energy balance and appetite. When body fat stores increase, leptin levels should rise, signaling the brain to reduce appetite and increase energy expenditure to maintain weight. Conversely, when leptin levels are low, the body interprets this as a signal of low energy reserves, which can trigger an increase in appetite and a decrease in energy expenditure, making it more difficult to lose weight and potentially leading to weight gain.

This hormonal imbalance is particularly significant in the context of obesity, where despite having higher levels of body fat (and therefore theoretically higher leptin levels), individuals can become resistant to leptin's effects, leading to continued overeating and weight gain. Thus, a deficiency or insensitivity to leptin can contribute to a cycle of weight gain.

Other hormonal levels, such as those linked to serotonin, growth hormone, or insulin, have their own roles in metabolic processes, but they do not directly trigger weight gain in the same way that low leptin levels do, especially in terms of appetite regulation and energy expenditure.