Updated: May 12
Body image issues, obesity, mental alertness, moods and emotional disorders, and eating disorders can be treated simply through fasting.
WHY INTERMITTENT FASTING WORKS
Whenever we eat, our body releases insulin to convert the sugars in food into energy. If there is no need to use the sugars immediately, insulin will also ensure the excess sugar is stored in our fat cells. This means that whenever we go without food for extended periods such as when fasting, insulin is not being released. The body will break down our fat cells for energy instead, and this can produce many benefits for the body from weight management and cellular cleanup to digestive support and better mental clarity.
The most popular intermittent fasting methods are the 16/8 protocol, Eat-Stop-Eat and the 5:2 Diet program. Select one of these methods, try it for 3 months and then report back on your results by leaving us a comment.
The 16/8 method: Also called the Leangains protocol, it involves skipping breakfast and restricting your daily eating period to 8 hours, such as 1–9 p.m. You then fast for the 16 hours in between. For the first 12 hours, your blood sugar and insulin levels will fall and stabilize, from the 13th hour, your body will enter a state of ketosis wherein it starts to burn fat for energy.
Eat-Stop-Eat: This involves fasting for a full 24 hours, once or twice a week. For example by not eating from dinner one day until dinner the next day.
The 5:2 diet: With this method, on two non-consecutive days of the week you consume only 500–600 calories, and eat normally on the other 5 days.
Many people find the 16/8 method to be the simplest, most sustainable and easiest to stick to. It’s also the most popular. However as all these methods reduce your total calorie intake, any of them should cause weight loss as long as you don’t compensate by eating much more during the eating periods.
You also don't need to change your usual diet, although dieticians do note that a nutrient-dense diet with a lot of plants and protein is ideal to help sustain you through fasting periods. Should you still struggle with hunger pangs, start by reducing your initial unrestricted eating period down to 10 hours, before transitioning to 8 hours.
WHAT HAPPENS TO YOUR BODY DURING FASTING?
Just remember to consult a professional before starting a prolonged fast. Fasting is contraindicated for some people that are prone to developing anorexia nervosa, body dysmorphia and many others.
0 to 4 hours
The first four hours after you eat are known as the anabolic growth phase. Your body is using up the energy you just ate to power your current activity and for cellular and tissue growth. During this phase, your pancreas produces the hormone called insulin. This process allows your body to use up the glucose that was released into your bloodstream after your meal and to store any excess energy in your cells for later use.
4 to 16 hours
The second phase kicks off after four hours and lasts up until about 16 hours from your last meal. This is the "catabolic," or breakdown phase when all those extra nutrients start being released from storage to be used for energy.
Once the energy stored in your cells runs out, your body starts to rely instead on stored fat. The process of releasing fat and burning it up for energy releases chemicals known as ketone for energy, which usually happens around the 16-hour mark.
The rate at which you reach this stage really depends on what you ate for the last couple of meals before your fast. If you ate a lot of carbs and starch, it will take a bit longer than if you ate mostly fats and protein.
One of the most powerful features of fasting, called autophagy, also kicks off during this phase.
Autophagy is triggered by a reduction in a growth regulator called MTOR, and this process is basically a spring cleaning for your cells. It gets rid of any dead or damaged cellular material, which can otherwise contribute to ageing, cancer, and chronic disease.
16 to 24 hours
Once you pass the 16-hour mark, glucose in the cells and glycogen in the liver and muscles begin to dwindle rapidly, which causes you to burn stored fat in order to keep up with your body's need for energy.
Your energy demands at this stage likely haven't changed much—you're still waking up, working, walking, interacting with people, maybe exercising—so the amount of energy that's needed can be quite significant.
The production of another chemical, AMP-activated protein kinase (AMPK), is also triggered at this point. This really increases the amount of autophagy happening all around your body.
24 to 72 hours
Once you pass 24 hours of fasting, your body will enter into a state called ketosis, where you're reliant on burning your fat stores for energy. As fat cells are broken down for energy, ketone bodies are created and released into the bloodstream.
Ketone bodies act as fuel for the brain when glucose is scarce. Glucose is our brain's primary source of fuel, but ketone bodies provide the brain with additional benefits. Burning ketones can lead to a major uptick in your cognitive performance, mental clarity, and a general sense of energy and well-being as you enter into a multiday fast.
Your brain also gets a boost around the 24-hour mark from an increase in the production of brain-derived nootropics factor (BDNF). BDNF supports the growth of brain neurons. Not only is it correlated with improvements in long-term memory, coordination, and learning, but it's also thought to be key in reducing the risk of developing Alzheimer's disease in later life.
Once you've been fasting for three days or more, your body enters a deep state of ketosis. All the previous benefits: Autophagy, the uptick in the production of beneficial chemicals and hormones, fat loss, and mental clarity continue to increase. That said, your thyroid hormones also start to get affected, as your body thinks it's starving.
Research suggests longer fasts can help your body become more resilient to stress and exposure to toxins and that certain hormones produced at this stage can have beneficial anti-cancer and anti-ageing effects. That said, people with a history of eating disorders should avoid prolonged fasts, and it's always a good idea to seek medical supervision when fasting.
Fasting is a powerful tool for improving your body's longevity, and it can have a really transformative impact on your health. Once again, if you plan to do any kind of extended fast, it's very important to work with your medical practitioner. By understanding these stages, you can choose the right type and duration of fasts for your body and your goals.
Enjoy the changes that come with fasting. Do share your results here with us. Contributing writer Alexis Shields, excerpt from mbghealth. Make an appointment with our therapist before you undergo an extended fast. Call +60123300415.