This is the secret to sustainable weight loss, enhanced brain function, reversing the ageing process, avoiding heart disease, cancer, dementia, even Covid! – and all of it FAST!

If I were to be allowed just one treatment to offer my patients for the rest of my medical career, without hesitation I would choose fasting.  This is because fasting is the most effective treatment for every medical condition.  It is simple and easy to apply, and it does not cost you a penny – in fact, it can help you to save money.

Different types of fasting

The different types of fasting include:

  • Absolute (dry) fast – no water or food, but you see double the benefit
  • A fast taking just water
  • Extended fasting is more than 3 days
  • Intermittent fasting is either a short fast, lasting less than 24 hours, or a longer one of more than 24 hours
  • Spiritual fasting has been used over the centuries to promote meditation and clarity of thought, the idea of sacrifice, and healing

Intermittent fasting is the most popular form.

Intermittent fasting prevented our ancestors, who were hunter-gatherers, from suffering with obesity and associated diseases.  Food has become more available over the last 10,000 years with the agricultural revolution.  But even up to the 1960s, it was not a problem, because people consumed whole food.  The obesity problem started with our modern diet, high in sugar and refined carbohydrates, and the concept of snacking between meals.  High insulin levels encouraged fat storage, obesity and associated diseases.

Intermittent fasting means periods of fasting, occurring regularly between periods of normal eating.  The fast can be 12 hours, 16 hours or even 24 hours.  Nutritional deficiencies are not a concern in shorter fasts.  Intermittent fasting usually refers to eating for 6 to 8 hours and fasting for the rest of the 24 hours.  16/8 intermittent fasting is an effective way to lose weight.

The benefits of intermittent fasting include bringing insulin levels down to facilitate fat burning, stimulating a growth hormone surge to preserve and grow muscle mass, cellular repair to slow down the ageing process, reducing inflammation and oxidative stress damage, benefiting the heart by reducing blood pressure, cholesterol, blood sugar and other inflammation markers, increasing cell repair, preventing diseases such as cancer, and improving brain function and preventing dementia.

Intermittent fasting has also been shown to benefit the immune system, increasing the number of macrophages and the secretion of IFN gamma to prevent bacterial and viral infections.  Another study concluded that intermittent fasting constitutes a promising preventive strategy against Covid-19.

During intermittent fasting, after 12 hours, you start to burn fat, at 18 hours you generate significant ketone bodies, at 24 hours you start recycling cell components, by 54 hours insulin drops to its lowest level, and at 72 hours the body breaks down old cells and builds new ones.

The types of intermittent fasting include:

  • 16/ 8: fast for 16 hours, with an 8-hour eating window during which to fit 2 or 3 meals. For instance, have your first meal at 10am, and last at 6pm
  • Eat–Stop–Eat: one or two days of 24-hour fasts per week
  • Alternate fasting: you fast every other day
  • The warrior diet: small amounts of fruit and vegetables during the today, with a big meal at night
  • Spontaneous meal skipping: skip 1 or 2 meals per week, when you don’t feel hungry or don’t have time to eat

You should try and have zero calorie beverages while fasting, and real, whole, healthy food during the eating window.  Cinnamon may also help to suppress your appetite.

Fasting in general

Fasting is a great tool to empower you take control of your health and life.

Fasting is a particularly effective and powerful therapy to manage the following conditions – obesity, stroke, dementia, high cholesterol, high blood pressure, fatty liver disease (known as non-alcoholic steatohepatitis), polycystic ovary syndrome (PCOS), gout, heart disease, GORD, obstructive sleep apnoea and cancer.

The advantages of fasting include:

  • Improved mental clarity and concentration
  • Reduced weight and body fat loss
  • Improved insulin sensitivity
  • Increased energy levels
  • Lower blood cholesterol
  • Ageing process reversed
  • Dementia prevented
  • Reduced inflammation

Most of my patients are happy to be convinced that dietary intervention will manage their conditions.  But the real winners are those who adopt the dietary intervention together with fasting.  Double interventions having a significantly bigger impact.

Fasting is voluntary abstention: the food is readily available, but you don’t want to eat for spiritual or health purposes.  Starvation is involuntary abstention: you are forced to stop eating due to a lack of food due to poverty, war or famine.

Fasting is the logical and effective way to lose weight, and it is perfectly safe.

Fasting consistently lowers your insulin levels, while food does the opposite: sugar and refined carbohydrates boast the highest insulin response, whilst fat shows the least.

The disappearance of the daily fasting

Some of you will be old enough to remember the pattern of eating in the 50s and 60s.  There were three meals – breakfast, lunch and dinner.  Typically, the first meal was at about 8am and the last meal at about 6pm.  There was no eating and no snacks between meals, and crucially 14 hours of fasting per 24 hours.  The change came in the 70s when snacks were introduced, and from that point on, obesity and associated diseases escalated progressively to reach epidemic levels early in the 21st century.

Insulin increases during meals (as I said, carbohydrates and protein stimulate insulin secretion, whilst fat has the least effect.)  Protein does not raise your blood sugar, but it does raise your insulin.  Amino acids, the protein building blocks, can be converted to glucose to top up blood level.  On the other hand, insulin stores excess energy as fat – it is also known as the fat storage hormone.  Fat is stored not only in fat cells (adipose tissue), but also in important organs such as the liver, pancreas and muscles.  This restricts these vital organs to mere fat storage space.

When you eat, the body absorbs sugar and stores the excess initially as glycogen.  However, due to the body’s limited glycogen storage capacity (about 2,000 calories), the excess calories in your food are converted into fat.

Eating is a high insulin state, whilst fasting is a low insulin state.  Keeping your eating and fasting balanced should give you no net weight gain.

When fasting, blood sugar and insulin levels drop.  Glycogen stores (energy which is immediately available to the body) last between 24 and 36 hours.  From 24 to 48 hours, the liver starts to breakdown amino acids, the smallest units of protein, to make more glucose – a process known as gluconeogenesis, literally “making new glucose.”

2 to 3 days after beginning your fast, your low insulin level stimulates the breakdown of fat to make energy (lipogenesis.)  This means you breakdown stored fat (triglycerides) into glycerol (sugar) and three fatty acids to make ketones.  This is particularly important for the brain, as more than 75% of the brain can use ketones, but a very small area of the brain requires glucose.

Glycerol is picked up by the liver to make sugar (through gluconeogenesis) to keep your blood sugar level steady for the sugar dependant brain section.

A growth hormone surge on day 5 of fasting preserves muscle mass: this is the warranty that your muscles are not going to be sacrificed to make energy.  Fasting is not only effective for maintaining the body muscle mass, but also a good level of testosterone is important for sexual health.

Our ancestors survived times of low food availability (famine), due to their ability to store and burn fat.  For the same reason, ladies store a good amount of fat around their hip area to be used during times of increased demand, such as pregnancy and lactation.

Fasting is not only helpful in treating diseases, but also beneficial if you would like to slow down the ageing process, prevent ill-health and prolong your enjoyable life span.

Does intermittent fasting heal the body?

In my opinion, fasting is a great idea – switching the body from sugar burning to fat burning.  Frankly, the idea of having 3 meals AND 3 or 4 snacks per 24 hours is silly.

Studies show that a one week fast is beneficial as an annual cancer prevention strategy.  A series of one-week fasts is very helpful in treating prostate symptoms.

When I mention ketoses, people’s minds jump straight to ketoacidosis, a very serious condition associated mainly with type one diabetes.  I must stress that this has nothing to do with nutritional ketosis (low carbs.)

Fasting and ketosis go together.  The Keto diet is a good introduction to fasting.  When you eat a low carbohydrate diet, moderate protein will keep your blood sugar and insulin levels under control, and healthy monounsaturated fat will keep your hunger at bay.

Nutritional ketosis teaches your body to burn fat.  You move from depending on limited stores of sugar glycogen (2,000 calories) to the huge fat store of over 50,000 calories.

Gentle exercise during fasting trains your body to burn fat faster, as this accelerates the glycogen burning in your liver and your muscles.

How to measure ketones:

  • Blood ketone meter.
  • Breath testing (Breathalyzer).
  • Urine ketone strips.

People with insulin resistance must quite often fuel with sugar and refined carbs (toast and jam, chocolate) because they cannot burn fat.

Other effects of fasting include clarity of mind – something that helped our ancestors hunt for their food successfully.

In studies, baseline growth hormone increased from 0.73 to 9.86 in two days of fasting to maintain muscles mass.  High growth hormone not only increases muscle mass, but also speeds up your recovery from a hard workout.  Athletes can train harder and recover faster.  Fasting has great benefits for bodybuilders.

Fasting differs from starvation, because it does not affect your basal metabolic rate (BMR), the energy you need for all non-exercise activities, like keeping warm, keeping your heart beating, digestion and gut function.  On the other hand, calorie restriction can reduce your BMR, can make you feel tired, cold and hungry.  This reflects the body’s intelligence in working out resources according to availability.

If fasting did reduce your metabolism, then the human race would not survive.  But, on the contrary, fasting increases basal metabolic rate by 13%, whilst maintaining your exercise capability.

Fasting does not makes you burn muscle; the body uses fat until your fat reserves go below 4%.  If we did not preserve muscle and burn fat, we wouldn’t have survived in times of famine, because you need your muscles to find food (hunting and gathering.)  Your huge fat energy stores are enough for you to walk or run for miles.

Depletion of nutrients is rare in short fasting (less than 24 hours); for longer fasting, people are advised to take multivitamins.

Diets and fasting

Please note that 97.5% of diet programs fail because they adopt the philosophy of “eat less, move more.”  That means reducing your calorific intake whilst increasing its expenditure, but this does not work, because the correct goal is not to reduce your net calories, but to reduce your insulin level.  The scenario of reducing your calorie intake, whilst having a high insulin level, will simply slow down your metabolism.

Instead, eating nothing is the way to achieve your goal – it is easy, simple, free, convenient and powerful.  Fasting can be added to any diet program to make it successful.

The “two-compartment” model

The single compartment model views all calories as equal, and stored in a single compartment, so the approach is just to eat less and burn more to lose weight.

The “two-compartment” model shows that you cannot burn any fat until you have lowered your insulin to stimulate fat burning.  This usually happens when you have burned most of your glycogen to lower the insulin level enough to trigger fat burning.  If you don’t eat and your insulin level stays low, you burn fat.  Therefore, fasting stops insulin resistance.

Your mental activity increases when you are hungry and decreases when you are satiated – just think how you feel after the big meal.

When you fast, you slow the ageing process by renewing body tissues.  Apoptosis is also known as programmed cell death: after reaching a certain age, body cells are programmed to commit suicide, and old cells are replaced with new.  Fasting stimulates apoptosis.

Autophagy means to eat oneself – the cell recycles broken and ageing cellular components and replaces them with brand new perfectly functioning ones!

Both apoptosis and autophagy are necessary to renew our bodies and slow the ageing process.

Fasting lowers your cholesterol: a study showed that 70 days of alternate day fasting reduces LDL by 25%.  Fasting also preserves HDL (the ‘good’ cholesterol), and improves other risk factors for heart disease, such as Hs-CRP, Lp(a).

Who should not fast?

We recommend you seek your doctor’s advice before you fast.  Some people should not attempt fasting, and these include severely malnourished and underweight people, those with a history of eating disorders, diabetics dependent on medication, children under 18 years, and pregnant and breastfeeding women.

What is allowed during the fast?

You are allowed non-calorific drinks like water, herbal tea, black tea and black coffee.

People seeking more comfort would add food such as bone broth, coconut oil, cream or butter with little negative effect.  Moving further to juice fasting would rest the bowel but may not achieve the full benefit.

Bone broth is good for fasting days, as it contains small amounts of protein, minerals, calcium and magnesium.  Gelatine and protein help diminish hunger.  It makes longer fasting more bearable.

As you can see, my friends, I am a great fan of fasting!  It can help with almost every area of your physical and mental health.  If you would like to share any experiences you may have of fasting, please do so.  And if you have any questions at all, please do not hesitate to ask them of me.  And I will try and get back to you FAST!  Thank you!



The complete guide to fasting, Jason Fung, MD with Jimmy Moore.;year=2020;volume=15;issue=3;spage=125;epage=133;aulast=Faris