Leptin’s Role in Obesity
The story of how the hormone leptin went from ‘cure for obesity’ to afterthought
How the human body stores energy (calories)
The human body stores energy in two main forms –
1. Glucose (sugar)
2. Fat (body fat).
Glucose is stored in the liver in long chains known as glycogen. Once the glycogen storage system is full, the body can turn excess glucose into fat in the process known as de novo lipogenesis. The body can also use two main forms of stored energy when food is not available — glucose and fat. This makes sense because it corresponds exactly to the way it’s stored.
Notice that glucose and fat comprise two of the three macronutrients — carbs, fat and protein. Protein is not primarily used as a fuel. Instead, it’s main role is as a building block for other proteins — muscles, connective tissue, skin, tendon etc. As a last resort, the body can use protein as a fuel, but it doesn’t want to.
The two forms of energy storage are complementary. Stored sugar (glycogen) is easily available because t’s right there in the liver. But the downside is that there is a limited capacity.
