Doctor's Heart Series Chapter 6 : Science of Fasting

Scientific explanation on benefits of Fasting/Caloric restriction.

Caution: Long read!

Alaska…

In the Far North, Arctic Ground Squirrel live well above the Arctic Circle in Alaska. Squirrel's unique ability is to hibernate(lack of food and water) for much of winter by dropping its temperature, heartbeats to 15/min, each respiration prolonged for a minute. They don't make excreta during this time and preserve every ounce of energy during the Hibernation. They hibernate due to the food scarcity, especially around Alaska(only a few months of warm temperatures and food). The ability to stay without food for months(sometimes 9 months) in times of adversity is very inherent to the mammalian species.

Arctic Ground Squirrel

Like Arctic ground squirrels, many animals hibernate as part of the natural life cycle due to various reasons, including seasonal, food scarcity, migration, and water resources. 

Cellular Mechanisms in Hibernation…

Now let us understand the mechanism of these animals undergoing Hibernation. The challenging event, including Hibernation, promotes cellular changes; we have to detour here to scientific explanation. Multiple events are happening during the Hibernation. Inside the Cell, the essential powerhouses are Mitochondria, which produce ATP. ATP is needed to generate energy inside the Cell, just as electricity is required to power the house. The consumption and utilization of oxygen in the formation of ATP results in Reactive Oxygen Species(ROS). The excess of ROS leads to oxidative stress( stress from the unstable atoms inside the Cell). The balance between ROS and Antioxidants is essential in nurturing the Cell. During fasting, one of the exciting things happens to be increased antioxidants and the balance of redox, which mitigates oxidative stress. Similar to animals, humans have the benefits of fasting.

Effects of fasting and cellular adaptations