Carbs, insulin, and fat gain: Doctor explains what really locks fat inside your body

What if fat gain had less to do with calories and more to do with hormones quietly running the show inside your body? A recent explanation by Dr Priyam Bordoloi has reignited debate around carbs, fats, and insulin, offering a clear biological lens into why some diets backfire despite good intentions. Using simple logic backed by clinical mechanisms, the doctor explains how everyday food choices can either lock fat inside cells or allow the body to burn it efficiently.

Dr Priyam Bordoloi took to X to explain that the human body is biologically hardwired in a counterintuitive way. According to him, when people cut fats from their diet and rely heavily on carbohydrates, especially refined ones, the body is more likely to store fat. In contrast, when carbohydrates are reduced and dietary fats are consumed, the body shifts toward burning fat. He emphasised that mastering insulin regulation is key to overall health, adding that MRI evidence consistently supports this pattern.

To help readers understand the science behind this process, Dr Bordoloi broke down what he called the “metabolic switch.” At the core of this switch is insulin. High carbohydrate intake causes insulin levels to spike, and insulin acts as a strong inhibitor of hormone-sensitive lipase, the enzyme responsible for breaking down stored fat. When this enzyme is blocked, fat breakdown becomes extremely difficult, regardless of how many calories are consumed.

Fat storage explaination from health expert

He used a simple lock-and-door analogy to explain fat storage. When insulin levels are high, the exit doors of fat cells are effectively locked. Even if a person is eating around 2,000 calories a day, elevated insulin prevents the body from accessing its own fat reserves. In this state, fat remains trapped inside cells rather than being used for energy.


Dr Bordoloi also highlighted the role of satiety in dietary choices. Fats and proteins take longer to digest and stimulate satiety hormones such as CCK and PYY more effectively than simple carbohydrates. This leads to a natural reduction in overall calorie intake, without the constant hunger or “starvation” feeling commonly associated with low-fat, high-carb diets.

Another key factor he explained is metabolic flexibility. When carbohydrates are cut, the liver is forced to produce ketones, shifting the body’s primary fuel source from sugar to fat. This transition turns the body into a more efficient fat burner, rather than one that constantly relies on glucose.


Through this explanation, Dr Priyam Bordoloi linked insulin control, diet composition, and fat metabolism into one clear biological framework, reinforcing his central point that insulin—not just calorie counting—plays a decisive role in whether the body stores fat or burns it.