9 Powerful Benefits of Intermittent Fasting
In this blog post I’m going to take you through 9 powerful benefits of intermittent fasting. It has become a very popular topic over the last few years because it’s fantastic for helping us with weight loss. But there are plenty of health benefits beyond weight loss.
I’m confident that once you know these you will want to give it a go!
Intermittent Fasting is something that I have practiced for several years and so have most of my clients here at Carb Dodging. As well as weight loss we have seen and learnt about some remarkable health benefits that I am going to share with you today!
Now why should you consider fasting at all… isn’t that a bit unnecessary you may ask?
Why should we deprive ourselves of food? Doesn’t that seem a bit like we’re punishing ourselves?
Table of Contents
Fasting Is The Normal
We haven’t always had access to an abundance of food, and of course, many parts of our modern world still don’t.
Humans did NOT evolve to eat all the time.
When our ancestors had to hunt for food, NOT eating for extended periods of time was normal.
Even a generation or two ago, we didn’t have endless coffee shops, take-aways, home delivery, and supermarkets open 24/7.
Typically, if we were lucky, we had 3 square meals a day and we easily fasted for 12-14 hours each and every night.
But now, the average person in the western world eats over a minimum period of 15hrs! And many much longer.
We evolved to deal with feast and fasting, and we definitely haven’t evolved to eat all the time.
Eating Regularly is a Modern Construct
So why is it so common to eat so frequently? We’ve already mentioned about the 24hr availability of food… Well, who is behind that?
The Food Industry… They want us to consume their products and lots of them. Clever marketing and easy access has led us to believe that we have to eat from the moment we wake up, eat all through the day, or how else could we possibly cope? And then all evening when we sit on the sofa.
The fitness and diet industry has even been taken over by food… claiming you must eat 5-6 times a day, you must fuel before, during and after a workout… even the kids are having sugary sports drinks at half time of their footy match.
WE DO NOT NEED TO EAT LIKE THIS….
We should work with our circadian rhythms
We have an internal clock system which regulates different bodily activities and functions. The most well known is the sleep-wake cycle to match the normal rhythms of night and day. The digestive system and the endocrine system release proteins and hormones at timings to suit the ‘normal’ wake cycle which should correspond with eating periods. The sleep cycle should correspond to a fasting period.
These are easily disrupted when we go against our natural biological clock and eat late into the evening and over prolonged periods of time.
So the big question is
“is switching back to a pattern when we eat for shorter periods, increasing our time spent fasting” going to improve our health?
Well… let me share this quote from a 2015 research paper…
“ several lines of evidence support the hypothesis that eating patterns that reduce or eliminate nighttime eating and prolong nightly fasting intervals could result in sustained improvements in human health… Prolonged nightly fasting may be a simple, feasible and potentially effective disease prevention strategy at population level”
A word about research
Before we dive into the benefits of Intermittent Fasting I just wanted to explain about the evidence behind Intermittent fasting.
Whilst there is a growing body of studies being conducted in humans,these studies are based on small groups of people. Much of the data from larger studies is based on animals, but it is believed that this is applicable to human health.
Unfortunately the majority of funding for scientific research stems from the Pharmaceutical industry who really have very little to gain from a drug free approach to health improvement.
That said, there are plenty of studies looking at the effect of shift work on human health , and shift work means a disrupted circadian rhythm and disordered eating patterns.
Which evidently leads to an increased risk of obesity, diabetes, CVD and some forms of cancer over the long term.
I certainly know from personal experience that working long shifts, late shifts and night shifts as a junior doctor was a time where I gained a significant amount of weight.
I’m sure if you’ve worked night shift’s you’ll relate to this!
Fasting Lowers Insulin Levels
Eating, (especially carbohydrates) causes our blood glucose levels to go up, and our pancreas responds by producing insulin. Insulin drives glucose out of our blood and into storage.
When we have prolonged periods of going without food it enables our insulin levels to drop nice and low.
High levels of insulin keeps us in fat storage mode due its hormonal effects. Low insulin means we can use our stored fat for energy and which is key for helping us to lose weight.
I’ve covered this in other videos and blog posts … “5 ways to lower insulin for weight loss”
and “Why do low carb diets work for weight loss? Here are 4 reasons”.
Can hormones disrupt our appetite?
Extended periods of eating can disrupt our appetite signaling… remember our circadian rhythm I mentioned earlier… well this can get all messed up so that we feel hungry much more often than we should.
Also, Leptin is released by our fat cells and should function as the off switch to eating when we are full. However, when we have obesity we often get leptin resistance due to its over stimulation. The brain then doesn’t receive the ‘off’ signaling properly and so stimulates us to keep eating. It also leads to decreased energy expenditure as the fed signal isn’t there and so we falsely think we are starving and need to conserve our energy.
One of the benefits of intermittent fasting is to help to reset these hormones so that our appetite is better regulated and we naturally want to eat less and so aid weight loss.
Frequent Eating negatively affects our gut microbiome
Diabetes Type 2 prevention (or reversal)
We have already mentioned insulin but did you know that hyperinsulinemia (chronically high levels of insulin) and insulin resistance are the root cause of Type 2 diabetes with or without the presence of obesity.
As we have seen, when we eat all the time, our insulin levels can stay raised in response to the sugar and carbs from our food.
Over time our cells try to resist the insulin trying to get them to take up the glucose. This is because they already have too much, which leads to higher amounts of insulin being produced in an effort to stabilise our blood glucose. Eventually the insulin can no longer maintain a healthy level and we have chronically elevated glucose levels in our blood. This leads to pre-diabetes and type 2 diabetes and all the awful health consequences of this disease.
Periods of Intermittent Fasting can dramatically improve our insulin levels, and our insulin sensitivity can start to be restored towards normal functioning.
Whilst our coaching program focuses primarily on weight loss, many of my clients have reversed their type 2 diabetes and pre-diabetes combining intermittent fasting with a low carb diet.
A word of caution here though; if you are already diabetic and on medication then please please consult with your medical practitioner first before introducing a low carb diet or Intermittent Fasting as you may well need your medication adjusting.
Reduced risk of Cardiovascular disease
Cardiovascular Disease (CVD) is mainly caused by underlying chronic inflammation in our blood vessels.
This causes damage to the inner cell layer of our blood vessel walls (the endothelium) and the development of plaques which can lead to blockages of the blood vessels within the heart muscle… angina, heart attacks, and within the brain…. Strokes.
Elevated Insulin Levels cause inflammation in the blood vessels
Once again, elevated insulin levels are at work, causing widespread inflammation and damage. In addition to this, fat cells themselves cause inflammation as they release something called cytokines.
Remember one of the hunger hormones Leptin I mentioned earlier? Well this too is inflammatory!
Too much Leptin signalling and too many fat cells also reduce the amount of Adiponectin being produced. Adiponectin is an important hormone that stops particles building up in the cells lining the blood vessel walls. This means it can be protective against Cardiovascular Disease. So a reduced level of adiponectin means the loss of this protection.
The beauty of Intermittent Fasting is it enables all this inflammation to be reduced and facilitates normal functioning of Leptin and Adiponectin, thereby reducing the risk of CVD.
May reduce the risk of Alzheimer's Disease
The lack of glucose causes an energy crisis in the brain causing the neurons to shrink and stop working properly. This “fuel shortage” can be present years before we notice any actual memory problems.
There is strong evidence that the brain is able to use ketones for fuel instead of glucose. Ketones are produced from the breakdown of fat and do not need insulin to get across the Blood Brain Barrier and so can bypass the problems with insulin resistance. Also, there are some studies suggesting that taking ketone supplements with or without a low carb diet might be helpful.
Ketones are produced when we fast as well as with a ketogenic diet.
So Intermittent Fasting may help to prevent brain degeneration and possibly improve symptoms if these are already apparent.
We’ve all experienced the discomfort of trying to sleep when we’ve eaten a heavy meal late in the evening!
Prolonged periods of eating distorts the natural circadian rhythm of digestion… we mentioned this a few times already. This has a knock on effect of causing poor quality sleep.
We know there is an association between poor sleep patterns and poor metabolism leading to obesity, diabetes and CVD.
When you don’t sleep well it also makes you tired and more hungry (as well as grumpy) and you are much more likely to overeat on carbs and sugar and of course gain weight.
And so starts the vicious cycle of continued hunger, distorted hormones, poor sleep and ultimately poor health.
Intermittent Fasting , or at the very least stopping eating in the late evening should help you to have better quality sleep and break the cycle leading to poor health.
So let me know in the comments below … How late do you typically eat your last meal or snack?
Increased levels of Human Growth Hormone
HGH production naturally peaks at puberty and decreases as we age. However we can make the levels drop more quickly through behaviours such as poor sleep and by eating too frequently.
We need to try to increase the production of HGH to increase muscle growth and prevent muscle breakdown. It is so important to maintain muscle mass particularly as we age, as losing muscle mass can lead to frailty and increased risk of falls and fractures. Loss of muscle causes weakness and can lead to the inability to function normally in everyday activities.
Scientific studies have demonstrated that fasting will increase the amount of HGH that is produced, quite the opposite to a common misconception that fasting causes muscle loss. Therefore fasting can help us to maintain adequate muscle to function well as we age.
This first section has considered the effect of our hormones on metabolism and how the risk of diseases associated with poor metabolic health can be improved and even prevented by Intermittent fasting .
The next 3 benefits are all related to the process of Autophagy, although this is still connected to the hormones we’ve already mentioned as you will see….
Autophagy is the process by which our cells get rid of damaged or unwanted parts and recycle them into fuel or new proteins. The term comes from the Greek word meaning ‘self’ and ‘eat’. It is an essential process to ensure healthy functioning of our cells which constantly need regenerating.
Autophagy is switched on by fasting and turned off by eating. It is linked to another cellular protein called mTOR which is the master regulator of nutrient signalling… basically influencing other hormones involved in the metabolism of our food. mTOR is active in the presence of insulin and is linked to cellular growth. It is suppressed by the presence of glucagon (absence of insulin) and therefore enables autophagy.
So you can guess that if insulin levels are chronically raised, mTOR is overactive and autophagy cannot happen.
Like all things there needs to be a balance… we need time for cellular clearance and time for cellular growth.
So how does this relate to health specifically?
We’ve spoken about Alzheimer’s disease already with respect to Insulin Resistance in the brain. But it’s also thought that eating too frequently may be involved in the build up of abnormal proteins that damage our brains.
In the brain of someone with Alzheimer’s disease, abnormal levels of Amyloid proteins clump together to form plaques that collect between neurons and disrupt cell function.
The brains of people with Parkinson’s disease contain abnormal clumps of proteins called Lewy bodies.
As we have discussed already, cellular proteins need to be replaced. It is thought that when autophagy is unable to occur due to the overstimulation of mTOR through the lack of fasting, it leads to neurodegenerative conditions.
“ autophagy dysfunction is strongly implicated in the pathogenesis of neurodegenerative disorders, including Parkinson’s disease and Alzheimer’s disease” (mTOR Signaling in Growth, Metabolism, and Disease Sabatini & Saxton 2017)
Fasting has also been shown, through the production of ketones to reduce inflammation and preserve energy supplies. These are associated with positive brain health.
We have seen that eating patterns which disrupt our circadian rhythms upset the balance of hormonal function. This prevents autophagy from happening and leads to poor metabolic health, disease and ultimately the ageing of our bodies at cellular level because they are unable to repair themselves.
I’m not claiming that Intermittent Fasting is the elixir of life BUT if we put ourselves in the position whereby we enable optimal cellular function we can go a huge way towards improving our ability to live and age well.
So, we have seen from these benefits of Intermittent fasting that it really can help to balance normal hormonal control of metabolism, cellular repair and regeneration. This enables us to have a lower risk of poor health, helping us to live and age well.
Why don’t you give it ago…..
Intermittent Fasting And Human Metabolic Health
Effects of Ketone Bodies on Brain Metabolism and Function in Neurodegenerative Diseases. (2020)
Ho KY, Veldhuis JD, Johnson ML, Furlanetto R, Evans WS, Alberti KG, Thorner MO: Fasting enhances growth hormone secretion and amplifies the complex rhythms of growth hormone secretion in man. J Clin Invest 81: 968 -975, 1988
Intermittent Fasting and Metabolic Health: From Religious Fast to Time-Restricted Feeding
Hartman ML, Veldhuis JD, Johnson ML, Lee M, Alberti KG, Samojlik E, Thorner MO: Augmented growth hormone (GH) secretory burst frequency and amplitude mediate enhanced GH secretion during a two-day fast in normal men. J Clin Endocrinol Metab 74: 757 -765, 1992
Prolonged Nightly Fasting and Breast Cancer Prognosis
mTOR Signaling in Growth, Metabolism, and Disease Sabatini & Saxton 2017
Ketone Bodies in Neurological Diseases: Focus on Neuroprotection and Underlying Mechanisms. Yang et al 2019
Induction of ketosis as a potential therapeutic option to limit hyperglycemia and prevent cytokine storm in COVID-19