Why would we want to avoid eating? It seems so utterly counter-intuitive to deliberately choose to go without food. Why would anyone consciously choose to do such an apparently unnatural thing, if they really don’t have to? In this blog we are going explain why this is not only something that you could do, but something you positively should do. This is especially true if longevity your goal.
In recent years, a lot of progress has been made in understanding how the human body is able to regulate itself if allowed to do so. Much of this progress stemmed from experimental observations that various creatures tended to have increased lifespans if their diets were restricted. Not only did they tend to live longer in fact, but they tended to be healthier as well. A new avenue of research was opened up that attempted to understand how this apparently paradoxical discovery could be explained.
What is Calorie Restriction?
Calorie Restriction, or CR as it is often shorted to, simply means reducing the number of calories in a diet. The reduction should be to a level whereby physiological changes are initiated, yet not to the level of malnutrition. It has been shown repeatedly to promote longevity in a range of animal studies. Usually, it is not only their lifespan that is increased but their healthspan too. The subjects tend to look healthier, and expend more energy far later into their lifespan, than those in control groups.
This effect was first noted in the early years of the 20th century. Originally, it was observed that calorie restriction slowed down the growth of tumours in mice (Francis Peyton Rous 1914). The earliest papers noting the effect on longevity in rats were published shortly thereafter (Mendel and Osborne, 1915 and 1917). Further studies followed throughout the course of the 20th century. Most of the results seemed to indicate a very clear finding: CR extends lifespan.
Beyond longevity, CR experiments on a range of creatures have been shown to offer a wide array of potential benefits. These range from protecting against arthritis and osteoporosis to preserving cognition, from delaying sarcopenia (age-related muscle wasting) to guarding colon health, from slowing the progression of cancer to fending off cardiovascular disease, and many more.
Given this huge range of benefits, and in particular the longevity effect, it is hardly surprising that many people have chosen to experiment on themselves, often before the science has become settled. With a few exceptions, most have generally with achieved reasonably positive results. Most of us do not have the decades required as the World waits for the data to come in. As ever with these things, the experimenter needs to guard against being too extreme, especially with CR. Fasting is one thing, starving is quite another.
The question has now become: how does CR produce these highly desirable effects? The answers are varied: increased insulin sensitivity, reduction in inflammatory markers, alterations to energy metabolism and changes in the sympathetic nervous system, all play a role. Upstream of all these though, and perhaps the clearest answer so far, is via the process of autophagy.
What is Autophagy?
The word ‘autophagy’ is formed from a combination of two Greek words: ‘auto’ meaning self, and ‘phagein’ meaning to eat. The notion is a process of self-eating, although the reality is not quite as gruesome as the word seems to imply. The self-eating referred to goes on at an intracellular level.
Autophagy is the cell’s way of recycling dysfunctional components: faulty organelles, misfolded proteins and other pathogens. Within the cell, a vesicle, known as a phagosome, surrounds broken down proteins and sub-optimal mitochondria and breaks them down into a form that can be re-used. We can think of it as a form of cellular house cleaning or recycling. At the first stage of this process, the phagosome is like a membrane that, over time, morphs into a cup-shaped autophagosome. Once it has gathered up the errant debris, it then joins with a lysosome. The lysosome contains enzymes that allow the intracellular garbage that has been collected to be broken down, prior to being re-used.
The process of autophagy is vital for maintaining cellular health and, by logical extension, the body’s health in general. Autophagy naturally occurs following periods of fasting. That period can be as short as twelve hours. The triggering of autophagy is one of the reasons that intermittent fasting has been so popular of late. Of course, its reputation for promoting longevity helps as well.
Our modern world is one of abundant availability of apparently endless food. This amount of temptation can be highly problematic in itself. By eating three meals a day, and constantly snacking, most of us never allow our bodies the space to do the internal house cleaning necessary for long term health. We are victims of our high standard of living and the temptation to endlessly eat.
Before continuing, a little credit where it is due here. The processes of working out the mechanisms involved in autophagy were originally elucidated by the brilliant Japanese scientist, Yoshinori Ohsumi. For this impressive scientific achievement, he was awarded a well-earned Nobel Prize in 2016.
For a more in-depth look into autophagy, and how the process can be consciously utilised, I would recommend James Clement’s excellent book: ‘The Switch’.
What is Keto?
The word ‘keto’ generally refers to ketosis or, more specifically, the ketogenic diet. This diet promotes burning fat as the body’s main source of energy. It does this by strictly limiting the number of carbohydrates that are allowed in the diet. This contrasts starkly with the more ‘normal’ carbohydrate-rich diet. The latter brings with it a huge range of problems that I discussed in a previous blog.
Some ketogenic diets are stricter than others. For most though, the limit for carbs is set in the region of 30 to 50 grams a day. The result of this limitation will be that the body runs out of glucose very quickly. At that stage, it will be forced to burn ketones, made from fat, as its main source of fuel. This is the process of ketosis. Because of this process, keto is a great diet for weight loss. Beyond just shedding the pounds, it also brings along a wide range of other benefits as well.
The ketogenic diet was originally developed in the early part of the 20th century. It was intended as a way of mimicking the effects of fasting. Researchers had discovered that symptoms would abate in epileptic patients who were fasting. Obviously, despite the benefits, the patients could not be fast forever. Therefore, a form of diet was developed to mimic these effects without the need to starve the patient. It was found that keeping dietary carbohydrates down to an absolute minimum would have this effect. Thus the ketogenic diet was born.
How can we Combine All Three?
Calorific restriction, in the form of intermittent fasting (otherwise known as time-restricted eating), fits very well with a ketogenic diet. To some extent, they are two routes to the same destination. They aid and abet each other symbiotically. Intermittent fasting will tend, much like keto, to put people into a state of ketosis.
In practical terms, it takes around twelve hours of fasting for the body to run out of its glucose stores and go into ketosis. It takes about the same amount of fasting to switch on autophagy at the cellular level. If the body is already low in glucose because of a ketogenic diet, the process will be accelerated.
Autophagy starts when insulin is low. Insulin levels will be decreased as we go deeper into a period of fasting. This hormone will also be naturally low in the case of a ketogenic diet. This beneficial effect is due to the restriction of dietary carbs. When carbohydrate is ingested, it is converted into glucose in the body which will cause insulin to spike. This spike is exactly what we are trying to avoid if we want to encourage autophagy.
These two interventions, intermittent fasting (calorie restriction) and a ketogenic diet fit together like a hand in a glove. Both of them are routes into ketosis and the desired cellular cleaning process state of autophagy, with all its health and longevity implications.
Over the last century or so, we have come to understand the body’s cellular maintenance systems at ever-deeper levels. From the initial discovery that calorific restriction tended to promote longevity in rodents to the understanding of autophagy, we have uncovered fundamental processes necessary for the upkeep of healthy cells. We have also come to understand how we can consciously and deliberately initiate these processes. By utilising such methods as intermittent fasting and the ketogenic diet, we can ensure that our bodies are able to cleanse themselves at the cellular level through the process of autophagy.