A question that seems to be asked with increasing frequency. And one for which the answer is never a straightforward yes or no.

Intermittent fasting

Intermittent fasting can be extremely useful in weight loss and therefore hormone balancing as fat is metabolically and endocrinologically active. The reason for this in the combined reduction in calories as well as stimulating the metabolism to switch gears to fat burning. The mechanism behind this is multifaceted but can be explained without too much difficulty.

During periods of extended fasting the body will adapt and reduce its energy expenditure by slowing enzymatic function and prioritising usage in the most important areas such as the brain. Shorter periods of fasting will switch the body from burning the available glucose into burning fats in adipose tissue, love handles to you and me, but it will not down-regulate overall metabolism and reduce energy expenditure dramatically. This switch can be further influenced by upregulating metabolism through movement and exercise; having a workout session just before eating.

After we have utilised a certain amount of stored glucose in the form of glucagon, the body will realise that stores are running low by means of hormone signalling. The brain can run on two forms of energy, ketones and glucose. Many people will say they can reach a fully ketogenic state however research shows that the brain always requires glucose as well.

Insulin is the hormone that knocks on the door of each cell requesting that the gates are opened to allow glucose in, to be utilised by the mitochondria for energy production. It only knocks if there is a rise in blood glucose. In some cases of chronically high blood glucose due to high dietary intake, the insulin must constantly knock on the doors of each cell hassling them to let the glucose in The cells become fed up with insulin interminably harassing them and start to ignore insulin as they do not need any more glucose. This can become a dangerous cycle driving both insulin and blood glucose higher as the glucose cannot get into cells for utilisation.

When there is a lot of glucose in the bloodstream it can start sticking to other molecules creating glycated proteins from LDL and other transport proteins. These are large sticky molecules that bump around in the blood stream creating havoc on blood vessel linings in the form of oxidative stress, which can lead to a number of health complications and chronic inflammatory disease states.

However during short periods (12-24hrs) of fasting, when blood sugar levels drop, there is no use for insulin so the production is reduced. This is a key factor for those with insulin resistance and diabetes type 2 (not type 1) (Barnosky et al., 2017). With less insulin circulating, the cells become more sensitive to its presence which reduces insulin resistance and improves sensitivity. This helps to explain the use for intermittent fasting in cases of chronic diseases including that of the liver (Vanhorebeek et al., 2017), inflammatory diseases such as Rheumatoid arthritis, oxidative stress, diabetes mellitis type 2, blood lipid imbalances and atherosclerosis.

Extended Water Fasting

Supervised water fasting has not been studied in depth however anecdotal data indicate positive effects of metastatic growths, gastrointestinal permeability reduction and therefore food sensitivities. Dr Goldhamer of TrueNorth in California has suggested that patients have normalised blood pressure, cholesterol, blood glucose levels, musculoskeletal issues and many more alongside removing lifelong dependency on medicines. Published data are hard to find, however.

Unsafe and Unsupervised Fasting

As you now know, with low levels of insulin and blood glucose, the body starts to burn fats through a process called beta oxidation. Adipose tissue or adipocyte store excess energy in the form of fats, adipose tissue also stores fat soluble chemicals and toxicants. Water soluble ones are quickly excreted, in many instances they were once fat soluble but are made more water soluble in the phase two of liver detoxification. If phase two is suboptimal one has a build up of fat soluble toxins which must be stored. Fat soluble molecules can more easily traverse across cell membranes which can be dangerous whereas water soluble ones must be transported by energy dependant transport proteins.

This may happen in the case of illness that requires medical intervention and drugs, exposure to pollution and organophosphates (fertilisers) as well as the more well known, alcohol use. The liver becomes overburdened and shunts what it cannot metabolise into storage in adipocytes to be dealt with at a later date. If that person then decides to go on a liver cleanse or a strong fast, the fat is mobilised to be burnt for energy and with that the stored toxins are released. If those toxins are potent enough, they can cause serious damage and, in very extreme cases, death. This is why gentle build ups and wise detoxification is advised before any prolonged fast.

Juice and Smoothie Fasting

A discussion that certainly stimulates heated debate. Choosing between each is highly dependant on the aim of the fast.

Smoothies include the whole vegetable and fruit. Done correctly, these are excellent however many slip up by making them into sugar based high fat litres of liquid that are not so dissimilar to just having a slice of iced cake. A mostly vegetable smoothie with a little fruit and small amounts of good fats gives an excellent source of fibre along with the ease of being able to consume a large quantity of plant foods in a quick drink. The fibre is excellent for manually cleansing the digestive system removing unwanted excess toxins, hormones and stuck foods as well as feeding the commensal bacteria in the colon, the is in relation to the enterohepatic circulation (Roberts MS, 2017).

Juices generally have a higher concentration of nutrients but lack fibre. This means less work for the digestive system as well as potentially higher sugar content per volume. This approach would be excellent for those who are trying to increase micronutrient consumption but may have digestive complaints. This would not be advised for those who suffer from constipation as the lack of fibre can slow transit time.

If you have no major health concerns or complications combining the two can be a great middle ground although if you have low blood pressure it is advised to supplement small amounts of sea salt or use sodium rich vegetables.


The advantages and disadvantages of any form of fasting will depend on the individual’s physiology, underlying diseases and metabolic variants. If you have a history of prolonged drug use, medicinally or otherwise, approach extreme fasting with caution. However a gradual introduction of intermittent fasting combined with antioxidant and liver supportive foods would be an excellent starting place. If you have any liver, kidney or lung problems seek the advice of a medical practitioner and look to have blood tests prior. Those with diabetes should approach longer term fasting with caution and seek medical supervision.

Although research may be a little thin on the ground, there is some evidence that various forms of fasting have beneficial health effects. When considering a fast, pose yourself a few questions to be sure you are making the right choices.

Do I have any serious health conditions that may be contraindicated for the fast I am considering?

Have I prepared properly in advance to reduce the risk of recycling excessive stored toxins?

Am I in a safe and relaxed environment to enjoy my fast and glean the most benefit from it?