By-Meena Ganagani,Practicing Clinical Nutritionist,Mumbai.
What is Fasting?
When you fast, you don’t eat or drink anything except water for a specific period of time. While fasting can be done for a number of reasons, it is usually recommended for those who are scheduled to undergo certain medical exams, including lipid and glucose tolerance tests. When preparing for a medical test, you need to fast for at least eight hours. Fasting for spiritual reasons may entail going for a single day, a weekend or even several weeks at a time.
Differences in Fasting and Starvation
The primary difference between fasting and starvation is the severity of symptoms experienced. People who fast for a short period of time may experience relatively minor side effects like hunger, headaches, dizziness, lightheadedness, low blood pressure and fatigue. In contrast, those who are starving can develop brain dysfunction, heart failure and convulsions and ultimately die of starvation if the condition persists. The longer an individual fasts, the more likely he is to expose himself to some type of starvation. (1)
What happens during Fasting?
Whether a person is fasting or not, the body still needs energy. Its primary energy source is a sugar called glucose, which usually comes from carbohydrates, including grains, dairy products, fruits, certain vegetables, beans, and even sweets.
The liver and muscles store the glucose and release it into the bloodstream whenever the body needs it. However, during fasting, this process changes. After about 8 hours of fasting, the liver will use the last of its glucose reserves. At this point, the body enters into a state called gluconeogenesis, marking the body’s transition into fasting mode.
Studies have shown that gluconeogenesis increases the number of calories the body burns. With no carbohydrates coming in, the body creates its own glucose using mainly fat.
Eventually, the body runs out of these energy sources as well. Fasting mode then becomes the more serious starvation mode. At this point, a person’s metabolism slows down, and their body begins burning muscle tissue for energy. Although it is a well-known term in dieting culture, true starvation mode only occurs after several consecutive days or even weeks without food.(2)
Health benefits of Fasting
In recent years, numerous studies have suggested that intermittent fasting – abstaining or reducing food and drink intake periodically – can be good for us, making it one of the most popular diet trends worldwide.
One of the most well-known intermittent fasting diets is the 5:2 Fast Diet – a plan that involves eating the recommended calorie intake for 5 days a week but reducing calorie intake to 25% for the remaining 2 days – to 500 calories a day for women and 600 a day for men.
Since the body is unable to get its energy from food during fasting, it dips into glucose that is stored in the liver and muscles. This begins around 8 hours after the last meal is consumed.
When the stored glucose has been used up, the body then begins to burn fat as a source of energy, which can result in weight loss.
A detoxification process also occurs, because any toxins stored in the body’s fat are dissolved and removed from the body,” he adds, noting that after a few days of fasting, higher levels of endorphins – “feel-good” hormones – are produced in the blood, which can have a positive impact on mental well-being.
When you starve, the system tries to save energy, and one of the things it can do to save energy is to recycle a lot of the immune cells that are not needed, especially those that may be damaged.(3)
Things to keep in mind while Fasting
- While fasting, make sure you drink enough water. Infused water liquids like lime juice, chhaas, lassi, fruit juices and whole, raw fruits are also recommended.
- Millets like amaranth seeds (rajgira), water chestnut flour (singhaare ka atta) have important minerals and B complex vitamins, and are also rich in fibre.
- Avoid eating fried foods like sabudana vada.
- Eating nuts, fruits, millets, and vegetables like pumpkin, sweet potato, milk, curd and buttermilk is good during a fast.(4)
Side effects of regular Fasting for certain people or in specific circumstances:
- People with eating disorders may end up binge eating more after fasting.
- Fasting and exercising at the same time may lead to low blood sugar (hypoglycemia), which can cause dizziness, confusion and lightheadedness.
- Fasting by people taking diabetes medications can lead to severe hypoglycemia and can lead to serious health issues.
- Skipping breakfast may be considered fasting by some because it can result several hours without food, but skipping breakfast can be unhealthy and has been associated with obesity.(5)