Fasting has been an integral part of many different cultures around the world for as long as there has been civilisation, often practiced in connections with religious ceremonies, such as during the Islamic holy month of Ramadan, the Christian season of Lent, or the Jewish holy day of Yom Kippur. In recent years fasting has also been scientifically proven to have have profound health benefits.
In modern society, with food being plentiful 24/7, we’ve been conditioned to think that we need to eat regularly throughout the day or we simply won’t have enough fuel to pull through. In actual fact, this is not the case at all.
Our ancestors would likely have had periods where food was scarce or perhaps not available at all and our bodies are built to cope with this. This is why we store fat in our bodies which we can feed off during times when there is limited food supply. This would have been the normal state of affairs during the colder months of the year, when food supplies were scarce.
People often force themselves to eat something, even when they are not hungry, as they believe that fuel in the form of food is required to stay awake and alert.
Insulin is the main hormone that informs your body whether to burn energy or store it. When you eat, insulin level rise, signalling your body to store energy. When insulin falls, it tells your body to release energy. When you develop insulin resistance though chronically elevated levels of insulin, your body is put in constant fat-storing mode.
Without the signal to burn stored energy, you end up feeling tired and sluggish. You have plenty of fuel available, but it's all locked up in your fat cells, remaining inaccessible until the insulin levels in your body drops. This is why it becomes very difficult to lose weight when you have developed insulin resistance.
The key to breaking this cycle is to have sustained low insulin for a lengthy period of time. This is why fasting can be so beneficial. Fasting lowers insulin more powerfully than any other strategy, which allows the energy stored as body fat to be used.
When you start being able to access your fat stores, you stop feeling lethargic and hungry because you are in fact eating up your own fat.
Dispelling the myths about fasting
Starvation? A worry that people have is that fasting is the same as starvation. This is not the case. Starvation is involuntary and fasting is voluntary. You have complete control. Many also think that when fasting they are telling their body to go into starvation mode, slowing the metabolism so that the body holds on to fat rather than burning it.
Starvation mode actually happens if you just try to cut calories. This doesn’t happen when fasting. Why? After an initial period where your body is adapting to burning fat instead of glucose (your body uses glucose if it is available, making the fat stores inaccessible) the basal metabolic rate will on average become ten per cent higher than when you started the fast. The body has switched fuel sources from burning food to burning body fat. This is also why fasting usually has the effect of increasing energy instead of leaving you feeling tired and lethargic. Fasting gives your body the golden opportunity to access the body’s own energy stores, which you previously had no access to, giving you a much greater supply of energy than if you were relying on stored glucose.
Loss of Muscle Mass? Many believe that fasting will result in the loss of muscle mass. In fact, when fasting, the body down-regulates protein catabolism and up-regulates growth hormone production.
Think about it this way. A kilogram of fat is approximately 7,000 calories. If you eat about 1,800 calories a day, it would take four days of fasting to burn a kilogram of fat. If you would like to lose 20 kilos, it would take 80 days to burn that fat. This means that you could at least in theory quite happily fast for this length of time!
Fasting also has many other beneficial effects on your body’s biochemistry, the sum total of which is that it profoundly supports your quest towards optimal health!
Different types of Fasting
There are many ways to do a fast. Below are some of the most common variants:
Water fasting. This is exactly what it says on the tin - no food, plenty of water, typically for 24 hours or longer.
Water and non-caloric beverage fasting. This is a slight twist on the water fast which permits other non-caloric beverages, such as tea and coffee, but with no milk, sugar/other sweeteners.
Bone broth fasting. For longer fasts, a variation is to allow bone broth, which contains healthy fats and protein. It’s not strictly a fast by its true definition, but many people who consume bone broth when fasting experience very good results.
Fat fasting. When fat fasting you are allowed to consume healthy fats in addition to water and/or non-caloric beverages. Adding healthy fats such as butter or ghee from grass fed cows, coconut oil, MCT oil and avocado can make fasting much easier to comply with. Such a fast may include bulletproof coffee (black coffee with butter and coconut/MCT oil), but there are many other ways of including healthy fats.
The reason why this can still be classified as a fast is that dietary fat only produces a minor insulin response, so you can still get most of the benefits of fasting. For those who are the most metabolically challenged, this may be the best approach to take when first embarking on a fast. It may take time for the body to become able to access its fat stores, and in the period before this happens, you will feel lousy and tired. Supplementing with some healthy fat sources may get you through this tough initial period.
Intermittent fasting (sometimes referred to as time restricted feeding - a term that I don’t favour as I love food and enjoy the ritual of eating, but do not approve of calling this civilised act feeding!) means that you schedule your meals so that you get a period of fasting each day, no less than twelve hours and ideally up to 16 hours or more, typically leaving you with a six to eight-hour window within which you eat all your meals for the day.
Try to figure out how this can most easily be implemented into your day. Many people find it easiest to skip breakfast. Others find it easier to skip dinner.
Bear in mind that one should try hard not to eat too late in the evening as this is the time when your body gets ready to rest, repair and regenerate. As a rule of thumb, try to avoid eating at least three hours before bedtime.
Insulin is one of the main drivers in weight gain. You will typically have a greater insulin response to food towards the end of the day.
It appears that the best approach is to have your main meal around midday to early afternoon, and have a lighter meal either in the morning for breakfast or in the evening, preferably no later than 7 pm.
Who should not fast?
Most of us would likely benefit from fasting, but it may not be appropriate for everyone. People who are underweight, malnourished, children and teenagers, pregnant and breastfeeding women, should avoid fasting.
You should also seek medical advice if you are taking any medication before you embark on any fasting regime. Some drugs may cause stomach upset if taken on an empty stomach.
If you are on diabetes medication, you risk having very low blood sugar levels (hypoglycaemia) when fasting which isn’t an issue if you are fat-adapted (where you would expect blood sugar levels to be consistently low) but would be if the fluctuations in blood sugar are great. Wearing a flash glucose monitor may be a good solution in such a case so that you can continuously follow the development of your blood glucose levels throughout the day.
If you have high uric acid there is a risk of gout, as fasting may result in an increase in uric acid levels because when you are not eating, your kidneys reabsorb uric acid at a higher rate.
The ketogenic diet as an alternative
As an alternative to fasting you could embark on a ketogenic diet, which would deliver similar health benefits, but the challenges can be greater when it comes to implementation and compliance. When on a ketogenic diet, it is necessary for you to reduce your carbohydrate intake drastically, eat only moderate amounts of protein and plenty of healthy fats with the effect that your body switches from burning carbohydrates to fats for fuel.
The ketogenic diet is more complicated than fasting as you have to find the correct level of carbohydrates that you can tolerate. If more carbohydrates are consumed than tolerated, you will not achieve ketosis (i.e. you will not be burning fat). Fasting also delivers quicker gains, jumpstarting the body’s shift in metabolic processes from burning predominantly glucose to metabolising fat.
You can do it!
The best thing about fasting is that it does not interfere with your life. In actual fact. it makes things simpler. You don’t have to think about what to eat or what not to eat and it is completely free! Skipping meals also saves you time! It doesn’t require any planning. You are left with loads of extra time during the day to do other things. This could be very liberating for a change.