What is it?
First, what it is not? It is not a diet. It is more a pattern of eating that specifies when you should or should not eat rather than what you should eat. Intermittent Fasting (IF) is a term for an eating pattern that cycles periods of fasting in between regular eating.
It is a trend that is gaining popularity across the world. People are using it for losing weight, improving body composition, decreasing body fat percentage, increasing lean muscle mass, and improving their overall health and decrease the risk of diabetes and cancer.
Why do it?
By making you eat less and helping you burn more If causes weight loss by changing both sides of a calorie equation. Additionally, it changes hormone levels to facilitate weight loss. When the body is in a fed and a post-absorptive state which together last for around 12 hrs after a meal, the insulin levels in the blood tend to be high and no fat burn happens. At around 12 hrs after eating, the body enters a fasting state and starts burning fat.
Studies have shown that decreasing calorie consumption by 30-40% can extend lifespan by a third or more.
Lower Insulin Resistance
Insulin resistance is a key factor for high blood sugar levels in type 2 diabetes, the most common form of diabetes. IF can reduce blood sugar levels by 3-6% and fasting insulin levels by 20-30%.
Improvement in heart health
If may reduce LDL, triglycerides and inflammatory markers, all of which increase the chances of heart disease.
Animal studies suggest that IF may reduce the incidence of cancers.
IF has been shown to increase the levels of a hormone called BDNF, which helps in nerve regeneration. It has shown some benefit in preventing neuro-degenerative diseases like Alzheimer’s.
How to do it?
Fasting during festive seasons or for religious purposes is quite common in India. IF is an eating pattern that makes fasting more regular and structured. There are several popular regimens of IF, but the 3 most common ones are:
Leangains or daily intermittent fasting
This involves a 16 hr fasting and an 8 hr eating window daily. The eating window can be any period of the day, eg: 8AM to 4 PM or 1PM to 9PM. However, all meals have to be eaten during this window and nothing except water to be consumed during the rest of the day. This is the most popular IF regimen.
Weekly intermittent fasting
It incorporates a 24 hour fast once a week. This can be from breakfast to breakfast, lunch to lunch or dinner to dinner.
Alternate day intermittent fasting
This is a little more intense and is the least popular. It involves 24 hr fasting period alternating with a 24 hr eating period.