Intermittent fasting is also known as intermittent energy restriction. The term intermittent fasting is an umbrella term for various meal timing schedules that move between voluntary fasting and non-fasting over a given time period. There are several different intermittent fasting methods, all of which split the day or week into eating periods and fasting periods.
As a habitual intermittent faster, the main benefits of this practice for me are as follows:
- greater focus and mental clarity,
- more physical energy,
- less body fat,
- healthy cravings for more nourishing, natural and less processed food.
“I fast for greater physical and mental efficiency”
“Note to self – When I eat crap, I feel like crap”
Research shows that the actual timing of your meals can have a profound effect on your waistline and your overall health.
Fasting doesn’t work just by helping you eat less. It works because it triggers some very powerful processes in the body.
“When it comes to fat loss, fasting beats dieting hands down”
One of the ways fasting helps you to lose weight is by reducing the amount of insulin circulating in your bloodstream.
Insulin is an important hormone; It works together with glucagon to keep your blood – sugar levels in balance when you eat. It also prevents the breakdown of your body’s reserves of fat.
Regularly eating throughout the day will keep your insulin level high and prevent your body from tapping into your fat reserves. However, When you fast, this allows your insulin level to drop and puts your body into fat burning mode.
Fasting is also more effective for weight loss than dieting because when you attempt to lose weight adopting a traditional diet, your body’s natural response is to rebel. Your body rebels because as far as it can tell, you’re facing some kind of threat to your food supply. Your body then responds by boosting ghrelin, a hormone that makes you feel hungry and lowers leptin, which tells you when you have eaten enough. In other words dieting can make you feel quite ravenous.
When dieting, in order to conserve energy, your body reduces its metabolic rate, or the number of calories it expends to keep you going. This means that while you are trying to eat less, your body adapts and starts requiring less, undoing all your hard work.
Fasting, however is different. Fasting allows you to draw on your stored fat so that your body does not react as though it is facing starvation when your food intake drops. Instead, you burn through the fat you have accumulated in your body and avoid the downsides that normal diets promote.
“The benefits of fasting go far beyond weight loss”
For the vast majority of people, the mere fact of weight loss is enough to persuade and encourage them to fast, however there are many other extensive benefits and reasons to fast, such as:
- Reduction in insulin levels – Excess insulin levels are linked to the development of type 2 diabetes. The reduction of blood levels of insulin also facilitate fat burning.
- Increase in human growth hormone – The blood levels of growth hormone may increase as much as 5-fold. Higher levels of this hormone facilitate fat burning and muscle gain and have a number of other benefits.
- Cellular repair – The body induces important cellular repair processes, such as removing waste material from cells.
- Gene expression – There can be beneficial changes in several genes and molecules related to longevity and protection against diseases.
“The bottom line is that when you fast, insulin levels drop and human growth hormone increases. Your cells also initiate important cellular repair processes and change which genes they express”
- Reduces oxidative stress and inflammation in the body – Oxidative stress is one of the contributing factors to aging and many chronic diseases. It involves unstable molecules called free radicals, which react to other important molecules ( like protein and DNA) and damages them. Studies show that intermittent fasting can reduce oxidative damage and inflammation in the body. This should have benefits against aging and the development of numerous diseases.
- Improves heart health – Heart disease is currently the world’s biggest killer. Intermittent fasting has been shown to improve numerous different risk factors, including blood pressure, total and LDL cholesterol, blood triglycerides, inflammatory markers and blood sugar levels.
- May help prevent cancer – Cancer is characterised by uncontrolled growth of cells. Fasting has been shown to have several beneficial effects on metabolism that may lead to reduced risk of cancer.
- May improve brain health – Intermittent fasting may increase the growth of new neurons and protect the brain from damage.
- May expand lifespan – Given the known benefits for metabolism and all sorts of health markers, it makes sense that intermittent fasting could help us to live a longer and healthier life.
How To Get Started – “Intermittent fasting” is a catch all term and it’s applied to a lot of eating styles.
One of the most popular types of intermittent fasting relies on what is referred to as an “Eating Window”. This means that food is eaten only during a set number of hours. People often refer to these windows in terms of ratios, with the numbers of fasting hours usually placed first. So 16:8 means 16 hours of fasting and 8 of eating, whereas a 19:5 means a 19 hour fast followed by a 5 hour eating window.
“OMAD” is an acronym for “One Meal A Day” and another type of intermittent fasting. Although this regime sounds extreme, this single meal can be eaten over a couple of hours.
Shorter eating windows like OMAD or 19:5 actually have greater benefits than longer ones. Research shows that fat burning accelerates significantly after 18 to 24 hours of fasting.
Eating windows aren’t the only way to fast. There’s also the “Up And Down Day” approach. “Up Days” are the days you eat, and “Down Days” are the days that you don’t eat.
People also use ratios to refer to these eating patterns, so 5:2 means five days of eating and two days of fasting.
Some people eat nothing at all on their down days. Others find it easier to have one small meal, usually up to 500 calories.
If you decide to opt for the “Up And Down Day” approach, then you should eat as much as you need to, on your unrestricted days. The variation between the up days and down days can help prevent your body from adapting to undereating, meaning that you’ll continue to lose weight in the long run.
There are a few things to avoid if you want to fast “clean.”
People in the fasting community often describe a fast that follows all the rules as a “clean” fast. This term doesn’t mean that only water may pass your lips during your fasting period, but it does narrow your choices. It means that while you are fasting, you need to avoid all sweetened and food like flavours, even if they are zero calories. This is because your body experiences an insulin response to certain tastes even if they are unaccompanied by actual calories.
A study in 2008 showed that just the taste of a sweetened solution in your mouth can significantly raise your insulin levels.
Therefore, all diet sodas, gum, flavoured water, fruit flavoured teas, and anything with a sweet or food like taste are ruled out.
Still water, sparkling water, black coffee and plain tea are some of the very few things that can be consumed while maintaining a fast.
It is important to stay hydrated while fasting but don’t undermine your fast by triggering your insulin response – when in doubt, leave it out!
To reap the greatest rewards, change your fasting style from time to time.
Changing your fasting pattern from time to time can help to drag you out of the homeostasis to which your body is inclined.
Homeostasis refers to your body’s natural tendency to maintain stability and balance.
By mixing up your fasting pattern, you stop your body from settling into any one rhythm.
There are 3 main ways to do this:
- Try switching your approach completely. If you’ve spent a month or two trying a 16:8 fasting regime, then perhaps try changing it to an up and down day regime.
- Try changing the length of your eating window. For instance, you could try 19.5 on some days and One Meal A Day on others! What matters here is keeping your body “on its toes”.
- Try adopting a hybrid approach whereby you fast on some days and don’t restrict your fasting on other days, and then also make use of eating windows.
“Fasting can help you to start eating healthily.”
Intermittent fasting is a powerful tool. It’s flexible, relatively simple, and helps you to lose weight and live longer.
However, although fasting can help you to reduce your weight and improve your health, it cannot defy the laws of nature. If you overeat during your eating window then you’ll put on weight.
Fasting shouldn’t be the only change you make to your lifestyle. What you eat, and how much you eat are also very important.
Studies have found that fasting helps to reduce levels of ghrelin, the hunger hormone, and increases the rates of leptin, the hormone that makes you feel satisfied.
In addition to reducing hunger, many people find that fasting actually changes their preferences in food.
Intermittent fasting will help you to develop cravings for the foods that are more nourishing and beneficial to your body as opposed to unhealthy and ultra- processed foods.