By Bhavna Malhotra
Consultant – Nutrition & Lifestyle
Email: bhavna.nutritionqueries@
Fasting has been an age-old practice universally. If it is ‘Navratri’ for Hindus, it is ‘Ramzan’ for
Muslims and ‘Lent’ for Christians. So why is fasting necessary for humans? Does it have any health benefits apart from fat loss? Was fasting survival tool for humans in caveman-era? As cave dwellers, humans had no choice but to fast in times of food scarcity but with the current abundance of food do we need to fast?
As per Wikipedia fasting is defined as willful refrainment from eating for some time. In a physiological context, fasting may refer to the metabolic status of a person who has not eaten overnight, or to the metabolic state achieved after complete digestion and absorption of a meal.
To understand how fasting helps us, we first need to understand the physiological changes that happen in our body post-meal. To make this complex process of digestion which involves the interplay of many hormones and enzymes more understandable, let’s look at it concerning only one hormone – Insulin. Every time you eat, your blood glucose levels rise as natural response insulin is released from the pancreas, which helps in getting the circulating glucose into the cells for nourishment and cell function. Once the cells have received the glucose as per their immediate needs the excess is converted to glycogen and stored in muscle and liver. If there is any further glucose available it is converted to fat and stored in your adipose tissue for use in times of crisis (read long fasting periods). It is this marvelous engineering of the body that made us humans survive the many famines and natural calamities over the decades!
With the improvement in farming methods, food production increased. The supply chain got the food to our tables more easily. We no longer had to go foraging for food. The abundance of food improved our nutritional status to start with, but with urbanization came the problem of inactivity. Our calorie intake soon surpassed the calorie expenditure leading to an increase in adiposity. Being in a fed state continuously led to an increase in fat stores which no longer were limited to subcutaneous stores (in the periphery) but started increasing in our viscera (fat around organs). This led to insulin resistance and chronic inflammation. Many studies have shown that chronic inflammation is one of the main reasons for the development of metabolic diseases like diabetes, hypertension, insulin resistance and some forms of cancer.
This suggests that humans were not genetically designed for current ‘food abundance’! Our ancestors probably understood this without any scientific studies and put religious fasting in place. However, one important thing to remember is that extremely long hours of fasting can lead to nutrient deficiencies, muscle loss, lowering of BP and heart rate and even death. So’ Intermittent Fasting (IF)’ is what has been recently studied for its health benefits. IF is an eating pattern where you cycle between periods of eating and fasting. There are several different intermittent fasting methods. Fasting for 12-18 hours and eating in a window of 6-12 hours being the most popular and studied one. Following are the documented health benefits of IF apart from fat loss:
IF- improves insulin sensitivity hence bringing down the insulin levels.
IF- increases the levels of human growth hormone facilitating muscle gain and fat loss
IF- helps to reduce abdominal obesity
IF- lowers inflammation in the body leading to lowering the risk of metabolic diseases like type 2 diabetes, heart problems and even some types of cancer.
IF- has even shown to increase the life span in rat studies. Although there is a lack of random controlled trials in humans to show the same but if our metabolic health is good doesn’t it become obvious that our lifespans and health spans would increase?
Traditionally our fasts permit us to eat healthy foods like millets, fruits, vegetables, nuts and dairy over the period of a day. These fasts never last for a period of more than 24 hours with ‘0’ food intake. Hence these fasts can be easily structured as intermittent fasts if we don’t binge of fried foods like chips and store-bought sweets. The idea of religious fasting was to take our attention away from food and focus on our inner energy to connect with the divine. Hence eating a snack every 2 hours on the day of fast defeats the whole purpose. Some might ask if ‘IF’ is just ‘cultural appropriation’ of just another fad diet? I personally wouldn’t agree with this argument as no culture ever advocated ‘living to eat’ rather than ‘eating to live’. This is ‘genetic appropriation’, i.e. eating just enough to thrive for which we were genetically designed.
