Many of us (me included) fear that if we were not to eat for an extended period of time that the hunger would build and build until it was simply impossible to deal with.
Except that hunger, like pain, like vision, like hearing is an output of the brain, not simply an input from the stomach. This concept reminds me of a story I will share in full taken from the Bodyinmind groups’ book “Painful Yarns”. We learn and remember things through stories, this one stuck with me, maybe it will you.
There’s a road in Australia called the Gunbarrel Highway. It might be a bit generous to call it a road - in some places it has not been graded since it was originally constructed, several decades ago. It is about 1400km long. It is called the Gunbarrell highway because the lead surveyor had a thing for neat straight lines on maps, so he did his best to make the highway as straight as possible. because of the long straight stretches, his construction team got the nickname the ‘gun barrel team’ and the name stuck. The highway links Wiluna in the west with Giles in the east. Wiluna is about 500km nor-noreast of Kalgoorlie. Kalgoorlie is about 600km east of Perth. Perth is officially the most isolated city in the world. I don’t know what that makes Wiluna, but it sure doesn't have a tube station. Giles is not far from Uluru, that mighty monolith right at the heart of the Australian continent and its people.
Why one might want to link Wiluna and Giles is not completely obvious. Wiluna consists of a service station, to service vehicles as they prepare for , or recover from, the highway; a general store; a pub and a camping ground. Giles consists of a remote meteorology station, known as Giles. The initial reason for building the road was to service a weapons research facility called Woomera. This part of Australia was considered by the British to be the best place in the world for a rocket range, presumably because it was a long way from Britain, and from where British constituents lived. It is certainly a part of the world not well suited to Europeans or their frigid descendants. Of course, people have been living happily in that part of the world for 60 000 years, but those people know things that most of us don’t. At each end of the gun barrel highway, there are strong warnings to take sufficient water for two days and enough fuel to get between stops, the longest gap being 600km.
One pair of clever fellows, Adam and Tony, decided to drive the gun barrel highway in their Lava Nida, as fast as they could. They were, apparently, experienced outback adventurers. They were also New Zealanders, which casts some doubt over the ‘outbackness’ of their adventuring, but that is a bit by the by. Adam and Tony had well designated roles and followed all the normal procedures.
That didn’t make up for the fact that they were in a Lava Nida, a vehicle notorious for being crap. The Lada lived up to its reputation and broke down smack bang in the middle of the longest unbroken stretch on the highway. All the electronics were out, which meant the car wouldn’t work. More importantly, it meant the two way radio wouldn’t work.
These two fellows - Adam and Tony, were a thousand km from anywhere worth being. It would have been 55 celsius in the shade (130 F), if there was any shade. The point is, it was hot. Damn hot. This is obviously a potentially dangerous situation. Any experienced rally team would be prepared for such an event and indeed, Adam and Tony were prepared, although they didn’t realise it.
One designated role that Adam had was to pack the water. After an hour or so in desert sun he went to get the water out of the back of the Lada and saw it was missing. Adam told Tony that somehow he must have forgotten to pack the water. They resigned themselves to having to sit it out - the ranger at Giles would expect them in about two days time and would give them a few hours grace. Adam and Tony hoped that help would arrive before death did and if not, that death would arrive via sleep and not via the dingos and eagles that would already be aware of the lame kiwis lying underneath their Lada Niva.
Now in this situation, one is sweating, as they say, ‘like a pig’ (which is a daft saying because pigs don’t sweat). Sweating leads to dehydration, which makes one thirsty. We all know that thirst is pretty much an upside down measure of hydration (or a right way up measure of dehydration). Don’t we? Read on my fellow hydroheathens! As time went on, these two lads were getting very, very dehydrated. They were also getting very, very thirsty. Just less than 48 hours later, they heard the distinctive drizzly drone of the Royal Flying Doctor Service Cessna and scrambled, with what little energy they had, to get something to wave. There on the back seat was a silver thermal blanket, which would contrast beautifully with the red sands on the desert. On ripping the blanket out, Tony saw, and immediately remembered, that when he replaced the spare wheel, he had moved the water from the trunk to underneath the thermal blanket on the back seat. They were so thirsty that the sight of the water sent them into a frenzy. They waved the sheet, noted the change in trajectory of the Cessna, which indicated that they had been seen, and started drinking. Adam and Tony drank like they were on their last legs, which they were.
Here is the groovy bit - by guzzling down a couple of litres of water, their thirst was quenched. The plane landed, the paramedics arrived, Adam and Tony indicated that they were not thirsty because they had just had plenty of water to drink. In actual fact, they were still so dangerously dehydrated that they both lost consciousness before the plane had swung around to head for Kalgoorlie Base Hospital.
Aside from narrowly missing the Darwins Awards, Adam and Tony’ experience demonstrates a critical aspect of thirst. After their big drink they were no longer thirsty, but they were still severely dehydrated. So, thirst does not tell us about hydration. Rather, it makes us drink. It works like this:
As you become dehydrated, blood volume starts to drop and receptors in your cardiovascular system respond to that drop. These receptors sit on the end of small diameter myelinated neurons. When the receptors are activated, they cause those neurons to send information (action potentials) to the central nervous system and thence the brain. The brain, outside of consciousness, evaluates this information in light of every other piece of information available, and evokes a response. In the first instance, the response may be to constrict blood vessels, reduce blood flow to non-critical areas, reduce respiratory rate. If the brain evaluates the situation as requiring a behavioural response from the organism, then a conscious experience will emerge - thirst. Thats the thing about thirst - it is the single best way to get someone to drink. As the proverb goes - ‘you can take a horse to water but you cant make it drink. Unless it is thirsty. So, it is thirst that motivates us to do what is required to get a drink. When you look at it this way, it is clear to see that thirst is a conscious experience that makes us do something. The wiggles, a children’s music band and Australias most successful entertainers, put it so eloquently in their absolute classic: “drink drink, drink some water, its so good for you”.
The other critical thing about this system is that when the brain is satisfied that enough has been done, then it will stop creating the experience of thirst. This is how we can make sense of what happened to Adam and Tony. P.39-44 Moseley, L. (2010).
This ‘yarn’ is one we use to help explain to our clients that thirst, like pain, is an output of the brain and is not a direct measure of hydration (thirst) or tissue damage (pain). These experiences are a call to take action and hunger is just the same, our challenge is ‘managing the hungry brain’ 2 much more so than the hungry tummy.
This is an important psychological barrier to overcome when considering significant calorie restricted days where we think we simply could not cope with the hunger. Hunger will pass and I’m not suggesting that it is easy, however, understand these hunger pangs are your brain driving you to eat and its easier to say no and simply keep yourself busy. The ability to postpone short term gratification has been shown to predict leaner individuals in the future, even as far ahead as 30 years!3,4 If you know you can eat normal again tomorrow, it becomes much more achievable to keep busy and not eat today knowing this.
Martin presented a case of one morbidly obese Scottish man in the sixties who didn’t eat for a whole year and while this case is exceptional and not recommended, it does demonstrate unusual will power and the fact that he did not starve to death. He came from 207kg to 82 kg by not eating and perhaps even more impressively, 5 years later was weighing in at 89kg.
An important note here is to remind that fasting, intermittent, continuous or otherwise is no magic bullet or panacea to weight loss.5 It is one strategy that Martin made a strong case, at least to me that is worth people trying to see if it works as a strategy to restrict calories over the course of a week, month or on off in 2 week cycles (such as the MATADOR STUDY, link to summary article below).6
I personally have had great success with many diet strategies including the paleo diet, ‘If It Fits Your Macros’ and in most recent years flexible dieting. One must not compare themselves to anyone else and especially me, I have a favourable genetic tendency to be lean, an extremely active lifestyle outside of my consistent training (what we call Non-Exercise Activity Thermogenesis or NEAT or background exercise) and an understanding of the research.
All of this makes it easier for me to look like this than many people I work with and help but honesty is important for realistic goals. I personally am playing with a version of the 5-2 diet for the next 4-8 weeks where I will learn how my body reacts to days training, teaching, working, travelling during a substantial calorie deficit. I am looking forward to 5 days a week eating maintenance (not surplus) calories where I stick to my usual good eating behaviours (see low hanging fruit below) but require no calorie counting. Just for reference Maintenance (the amount of calories and exercise you do to neither gain or lose weight) for me is approximately 4,000 calories per day. Yours will likely be MUCH lower than this (2-3000??).
Two days per week I keep my calories UNDER 1000 which is about 25% of my maintenance and that comes in the majority from protein (to muscle spare) and kept to the end of the day including a chocolate bar (delay discounting, postpone short term gratification and make it possible to adhere too). I am two weeks in and as long as I restrict on very busy days (I have chosen Mondays and Wednesdays when I train, lecture in University, run my private rehabilitation practice and have lots of meetings. I am already relatively lean so this isn’t the prime focus for me, but energy levels, hunger pangs and general productivity is what I am most interested in and it really hasn’t been that bad. Lots of coffee and always go to bed on a full tummy (example one meal per day below). Will power for a day, then eat normal (not compensate and overeat!) the next day and enjoy a party on the weekend, a few beers or desert absolutely guilt free.
Martin calls this giving yourself “unconditional permission to eat” and places you in the centre of control. “I’m choosing to diet aggressively but I know I can have a maintenance day anytime and no food is off limits”
One suggestion I would recommend if you have no idea what maintenance calories are for you, is to track your normal diet using MyFitnessPal for a period of time to gauge what is normal for you. However if you really cant get on with that (some can’t) then picking a couple of days to restrict calories to under 1000 will almost certainly lead to weight loss, providing you don’t overeat on the other days.
Thanks for reading and good luck if you are feeling motivated to give it a go. To learn more about evidence based nutrition I recommend you check out the conferences and online courses at MACNutrition or if you are fortunate enough to live in and around Mid Wales contact us for one of our health programmes to support and guide you.
Luke R. Davies,
Moseley, L. (2010). Painful Yarns, Metaphors and Stories to Help Understand the Biology of Pain, Dancing Giraffe Press, Australia, P.39-45.
Guyenet, S. (2017). The Hungry Brain; Outsmarting the Instincts that Make us Overeat, Penguin, Random House, UK.
Pinto et al. (2019). Intermittent Energy Restriction is Comparable to Continuous Energy Restriction for Cardiometabolic Health in Adults with Central Obesity: A Randomised Controlled Trial; the Met-IER Study, Clinical Nutrition (IN PRESS).
Byrne, N. M., Sainsbury, A., King, N. A., Hills, A. P. and Wood, R. E. (2018). Intermittent Energy Restriction Improves Weight Loss Efficiency in Obese Men: The MATADOR Study, International Journal of Obesity, 42(2), P.129-138.