The idea of skipping a meal or two may not sound too appealing to most of you. It might seem counterintuitive in fact, especially since we are used to eating on average ~ 3 meals a day.
Days are stressful and food is rewarding. I get it. Sometimes we need that crutch just to get us through the day. Not just that, but without food you feel moody, drained and just generally depleted. Thats why the very idea of going without seems crazy.
But, if you have IBS or a leaky gut, then chances are that food, even ‘safe’ foods sometimes make you feel like that anyway. So you’ve got nothing to lose, right?
Im going to throw in a quote which I think applies to fasting pretty nicely:
“I’m convinced that the best solutions are often the ones that are counterintuitive – that challenge conventional thinking – and end in breakthroughs” – Nathaniel J. Wyeth
As much as I like quotes, I like science more. Lets take a look at some of it, and see why fasting might be a legitimate approach to dealing with an irritable bowel.
Digestion requires effort
When you eat, your body goes to work breaking down, assimilating and absorbing those nutrients. This requires a degree of labour for your digestive system – about 25% of the calories from each meal.
When you digest food, your body shifts its focus and resources away from other physiological processes, like growing and repairing. Your immune system also has to be on alert, screening what passes through the gastrointestinal tract.
If you eat 3 meals a day, and have a few snacks in between, then chances are that your digestive system hasn’t had much time off.
Overloading the digestive system isn’t ideal, even for the most robust of guts, let alone an irritable one.
When you eat, you instruct your body to digest what goes in it. This alters the way your genes are expressed – how they behave. So why is that a big deal?
So, the heavy digestive work takes around 7 hours give or take, until you start heading towards a fasted state. Its only after that 7 hours that the digestive process cools off. As you may be thinking right now, its not often that 7 hours goes by without at least a coffee, snack or meal, in daylight hours at least. Anything that has to be metabolised will change your gene expression away from a fasted state.
Fasting alters your physiology
It turns out that when you aren’t processing food, your genes actually begin to express themselves in a very restorative manner. You could call it healing mode.
This is the counterintuitive part. Fasting is distinct from starvation. Skipping a few meals, a day or even a few days as part of a water fast isn’t going to kill you. Whereas starvation eventually will.
When you fast, you actually shift your energy pathways away from using glucose (sugar) and start to burn fat. Your body only has ~ 2,500 Kcal of stored glycogen to use as glucose. But, it has > 100,000 Kcal of stored fat to burn as fuel.
It takes time to shift towards fat burning pathways, which is why you may feel crappy until day 2/3 of a prolonged fast. A study that fed mice within an 8 hour window (16 hours fasted) found fat oxidation to be significantly increased. This suggests that fasting could promote better use of fat as fuel in humans, so you wont starve.
Besides just surviving on fat, your body also shifts towards some other beneficial adaptations.
Inflammation is at the root of many, many chronic diseases. It is something that our modern diet and environment does quite well at inducing. IBS, and leaky gut are not so different to inflammatory bowel disease in one respect – there is a degree of chronic inflammation at work. In fact, this inflammation is what causes damage to the gut wall allowing it to ‘leak’. You’ve even got these leaks to thank for some of your symptoms.
Bottom line is that Inflammation sets the bowel up for irritation.
Regular exposure to environmental toxicity (which exist on foods), allergenic foods, processed food, drugs, alcohol, even some medications – they all cause inflammation. These are the things that pass through our GI tracts all day everyday!
Its no mystery that a bowel can become irritable when overloaded with toxicity. This is compounded by the fact that stress is inflammatory. I don’t have to tell you how much your bowels are affected by stress.
Back to genes.
When you fast, nothing passes through your GI tract except water. Not only does this stop the flow of potentially inflammatory compounds, it reduces inflammation even further. When in a fasted state, there is greater activity of anti-inflammatory cytokines, and less activity of pro-inflammatory cytokines – this puts the body into an anti-inflammatory, disease mitigating state. Your genes know when you are fed or not, and they instruct these changes.
Inflammation & Oxidative Stress
Fasting reduces oxidative stress via your genes. This is the damage that occurs to cells from exposure to toxicity. The proteins, lipids and DNA of cells are actually affected, and ultimately change the function of those cells. This process is exactly what anti-oxidants prevent, so its important to activate them within you, and eat them when not fasting.
Interestingly, the development of IBS is linked to increased levels of oxidative enzymes, and reduced activity of antioxidant enzymes. This is what causes progressive damage to your cells, retarding their function.
Cells matter, after all they make up the organs which handle digestion. Progressive damage to even one organ in the digestive system can throw the whole process out of line, producing symptoms of IBS.
Fasting may be a powerful intervention for IBS and a leaky gut due to the reduction in oxidative stress. Whilst exposure to toxicity is minimised and inflammation subdued, the cells of the body may have room to regenerate.
Fasting & The Migrating Motor Complex (MMC)
At the root of many IBS symptoms are the bacteria in your gut. You’ve probably heard of SIBO (small Intestinal Bacterial Overgrowth) and dysbiosis (microbial imbalance). This basically means the microbial community is out of whack, which often causes the gut to become leaky.
Interestingly, fasting might actually help reshape the composition of the gut microbiome. This is under control of the MMC.
The MMC is a mechanism which controls stomach and small intestinal contractions in a cyclical pattern over a period of ~ 2 hours. Its function is to essentially perform housecleaning throughout the GI tract, sweeping bacteria and undigested food particles out for elimination.
The MMC is instructed by a complex orchestra of Neurohormonal signals in response to feeding/fasting, including but not limited to Ghrelin, Motilin, Serotonin and Somatostatin.
MMC activity peaks in between meals, in the absence of food. The presence of food and nutrients interrupts and decreases MMC activity, and essentially steers hormonal control back towards digestion and assimilation.
When the MMC is given the time and space to do its thing, it becomes more difficult for food and bacteria to hang around. This is why fasting could be a viable anti-SIBO measure.
In time restricted feeding studies (type of fasting), TRF restored a variety of beneficial strains of bacteria in mice.
When and how you decide to eat can induce changes in the gut microbiome that contribute to the diversity of gut microbes. This presents a mechanism by which those bacteria affect us, our metabolism, immunity and digestion!
There is only one study (that I know of) that has investigated the effects of fasting on IBS specifically. The results were quite promising.
36 subjects underwent fasting therapy for a period of 10 days and were progressively re-fed for 5 days after. Compared to the 22 subjects in the control group (conventional pharmacotherapy), the fasted group reported a significant improvement in symptoms. Those symptoms were abdominal pain-discomfort, bloating, diarrhea, anorexia, nausea, anxiety, and interference with life in general. The control group only reported improvements in 3 symptoms – pain, bloating and life in general.
Although the 10 day controlled protocol is hard for me or you to replicate, it is worth seeing what a less severe protocol could do.
You don’t have to starve yourself to fast. Starvation is different from fasting. Think of fasting as a kind of strategic way of eating. Whereas starvation is just not eating at all, until its time to check out – not ideal.
There are in fact many ways which you can choose to fast. The most common fasts include water only. Longer water fasts > 48 hrs may require micronutrient and electrolyte support, in addition to supervision under a professional.
If you choose to do it intermittently, the idea is to limit the window which you consume food in, and fast for the remaining 24 hours.
You can start with:
- 12 hours fasted // 12 hours fed
- 14 hours fasted // 10 hours fed
Then progress onto:
- 16 hours fasted // 8 hours fed (repeat every other day)
- 16 hours fasted // 8 hours fed
- 19 hours fasted // 5 hours fed
- 20 hours fasted // 4 hours fed
- 1 day fasted // 6 days fed
You might choose any of these and do them intermittently, mixing up the windows which you eat in. Have a play around and see what works for you.
- 24 Hours – from dinner to dinner / lunch to lunch. You effectively eat once/ day which you can do a few days/week.
- 36 Hours – eat breakfast on day 1, then fast for all of day 2 to eat breakfast again on day 3. You may choose to do this 1 maybe 2 times a week initially for a big gut healing push. Then continue with shorter fasts.
- Fasts beyond 48 hours can be done but require support with micronutrients and supplements. Make sure you know what you are doing with these.