Part 1 . History and use of sugar

     Imagine a chemical substance that can intoxicate us, can infuse us with energy, and can do so when taken by mouth. It doesn’t have to be injected, smoked, or snorted for us to experience its sublime and soothing effects. Imagine that it mixes well with virtually every food and particularly liquids, and that when given to infants it provokes a feeling of pleasure so profound and intense that its pursuit becomes a driving force throughout their lives. Overconsumption of this substance may have long-term side effects, but there are none in the short term—no staggering or dizziness, no slurring of speech, no passing out or drifting away, no heart palpitations or respiratory distress. When it is given to children, its effects may be only more extreme variations of the apparently natural emotional roller coaster of childhood, from the initial intoxication to the tantrums and whining of what may or may not be withdrawal a few hours later. More than anything, our imaginary substance makes children happy, at least for the period during which they’re consuming it. It calms their distress, eases their pain, focuses their attention, and then leaves them excited and full of joy until the dose wears off. The only downside is that children will come to expect another dose, perhaps to demand it, on a regular basis, so more or less works like a drug. Well, this substance exists and is called sugar!
    Biochemically, the term “sugar” refers to a group of carbohydrate molecules consisting, as the word “carbohydrate” implies, of atoms of carbon and hydrogen. The names of these carbohydrates all end in “-ose”—glucose, galactose, dextrose, fructose, lactose, sucrose, etc. and all of them will dissolve in water and they all taste sweet to us to a greater or lesser extent. When physicians or researchers refer to “blood sugar,” they’re talking about glucose, because it constitutes virtually all of the sugar circulating in our blood.    However, the more common usage of “sugar” refers to sucrose, the white crystalline variety that we put in our coffee or tea or sprinkle on our morning cereal. Sucrose in turn is composed of equal parts glucose and fructose, the two smaller sugars (monosaccharides, in the chemical lingo) bonded together to make the larger one (a disaccharide). Fructose, found naturally in fruits and honey, is the sweetest of all these sugars, and it’s the fructose that makes sucrose particularly sweet. Although sugars like fructose, glucose, and sucrose are found naturally in foods that humans have always eaten, modern foods often contain refined, processed sugars that are anything but natural.
    Without refining, the juice of sugarcane is for local consumption only. Within a day of cutting, the sugarcane stalks will begin to ferment and then rot. But the juice can be squeezed or crushed or pounded out of the cane, and that, in turn, as farmers in northern India discovered by around 500 B.C., can be transformed into a raw sugar by cycles of heating and cooling—a “series of liquid-solid operations.” The sugar crystallizes as the liquid evaporates. One end product is molasses, a thick brown viscous liquid; another, requiring greater expenditures of time and effort, is dry crystalline sugar of colors ranging from brown to white. The greater the refining effort, the whiter and more pure is the end product. When cultivated with the instruments of modern technology, sugarcane can produce (as the sugar industry and nutritionists would state in its defence repeatedly in the twentieth century) more calories per acre to feed a population than any other animal or plant. It can survive years of storage; it travels well; it can be consumed on arrival unheated and uncooked. And, unlike honey or maple syrup, it has no distinctive taste or aftertaste. Refined sugar is colourless and odourless. It is nothing more than the crystallised essence of sweet. Other than salt, it is the only pure chemical substance that humans consume. And it provides four calories of energy per gram.
    

    Anthropologists believe that sugarcane itself was first domesticated in New Guinea about ten thousand years ago. As evidence that it was revered even then, creation myths in New Guinea have the human race emerging from the sexual congress of the first man and a stalk of sugarcane. The plant is technically a grass, growing to heights of twelve to fifteen feet, with juicy stalks that can be six inches around. In tropical soils, sugarcane will grow from cuttings of the stem, and will ripen or mature in a year to a year and a half. The juice or sap from the cane, at least the modern variety, is mostly water and as much as 17% sugar. This makes the cane, sweet to chew but not intensely so. Anthropologists assume that early farmers domesticated the cane for the sweetness to be derived from chewing the stalks and the energy it provided. Well before the art of refining came along, sugarcane domestication had already spread to India, China, the Philippines, and Indonesia.
    It’s a safe bet that humans have tried to extract sugar, at one time or another, from pretty much every substance or plant that was noticeably sweet and held the promise of offering its sugar up in quantity. Honey was consumed throughout Europe and Asia before sugar displaced it, and when European colonists arrived in the New World and found no honey, they introduced honeybees, which Native Americans took to calling the “English Man’s Fly.” Native Americans were using maple syrup as a sweetener before the Europeans arrived, and they introduced the colonists to the taste. (Thomas Jefferson was a proponent of maple syrup because it rendered slave labor unnecessary. The sugar maple, he wrote, “yields a sugar equal to the best from the cane, yields it in great quantity, with no other labor than what the women and girls can bestow….What a blessing.”) But neither maple syrup nor honey can be used to sweeten cold beverages, and neither mixes well with coffee. Neither could be produced in the quantities necessary to compete with sugar. We still consume them, but in limited quantities and for limited uses.
    Crusaders brought sugar home with them to Europe after their campaigns in the Holy Land, where they encountered caravans carrying "sweet salt”. Early in the 12th century, Venice acquired some villages near Tyre and set up estates to produce sugar for export to Europe, where it supplemented honey as the only other available sweetener. Crusade chronicler William of Tyre, writing in the late 12th century, described sugar as "a most precious product, very necessary for the use and health of mankind". The first record of sugar in English is in the late 13th century.  Known worldwide by the end of the medieval period, sugar was very expensive and was considered a "fine spice", but from about the year 1500, technological improvements and New World sources began turning it into a much cheaper bulk commodity.    
    Contemporaries often compared the worth of sugar with valuable commodities including musk, pearls, and spices. Sugar prices declined slowly as its production became multi-sourced throughout the European colonies in the Americas. Once an indulgence only of the rich, the consumption of sugar also became increasingly common among the poor as well. Sugar production increased in the mainland North American colonies, in Cuba, and in Brazil. The labour force at first included European indentured servants and local Native American enslaved people. However, European diseases such as smallpox and African ones such as malaria and yellow fever soon reduced the numbers of local Native Americans. Europeans were also very susceptible to malaria and yellow fever, and the supply of indentured servants was limited. African slaves became the dominant source of plantation workers, because they were more resistant to malaria and yellow fever, and because the supply of enslaved people was abundant on the African coast. In the process of whitening sugar, the charred bones of dead enslaved people were commonly substituted for the traditionally used animal bones. During the 18th century, sugar became enormously popular. Great Britain, for example, consumed five times as much sugar in 1770 as in 1710. By 1750, sugar surpassed grain as "the most valuable commodity in European trade — it made up a fifth of all European imports and in the last decades of the century four-fifths of the sugar came from the British and French colonies in the West Indies. From the 1740s until the 1820s, sugar was Britain's most valuable import.

    Sugar was “an ideal substance,” says Sidney Mintz in his book “Sweetness and Power: The Place of Sugar in Modern History”.  “It served to make a busy life seem less so; in the pause that refreshes, it eased, or seemed to ease the changes back and forth from work to rest; it provided swifter sensations of fullness or satisfaction than complex carbohydrates did; it combined easily with many other foods, in some of which it was also used (tea and biscuit, coffee and bun, chocolate and jam-smeared bread). No wonder the rich and powerful liked it so much, and no wonder the poor learned to love it.” Unlike alcohol, which was the only commonly available psychoactive substance in the Old World until sugar, nicotine, and caffeine arrived on the scene, the latter three had at least some stimulating properties, and so offered a very different experience, one that was more conducive to the labor of everyday life. These were the “eighteenth-century equivalent of uppers,” writes the Scottish historian Niall Ferguson. “Taken together, the new drugs gave English society an almighty hit; the Empire, it might be said, was built on a huge sugar, caffeine and nicotine rush—a rush nearly everyone could experience.”
    Sugar is extraordinarily useful in food preparation, even when sweetness is not necessarily the desired result, and this is one reason why sugar in all its various names and forms is now ubiquitous in modern processed foods. Sugar allows for the preservation of fruits and berries by inhibiting the growth of micro-organisms that would otherwise cause spoiling. As such, inexpensive sugar made possible the revolution in jams and jellies that began in the mid nineteenth century . It inhibits mold and bacteria in condensed milk and other liquids by increasing what’s called the osmotic pressure of the liquid. It reduces the harshness of the salt that’s used for curing and preserving meat (and the salt increases the sweetness of the sugar). Sugar is an ideal fuel for yeast, and thus the rising and leavening of bread. The caramelisation of sugar provides the light-brown colours in the crust of bread. Dissolve sugar in water and it adds not only sweetness but viscosity, and thus creates the body and what food scientists call the “mouth feel” of a soda or juice. As a seasoning or a spice, it enhances flavours already present in the food, decreases bitterness, and improves texture.
    Mintz has argued as well, that a primary reason that helped sugar through the centuries to escape religious-based criticisms, of the kind pronounced on tea, coffee, rum, and even chocolate, is that, whatever conspicuous behavioural changes may occur when infants consume sugar, it did not cause the kind of “flushing, staggering, dizziness, euphoria, changes in the pitch of the voice, slurring of speech, visibly intensified physical activity, or any of the other cues associated with the ingestion” of these other substances. Sugar appears to be a substance that causes pleasure with a price that is difficult to discern immediately and paid in full only years or decades later. With no visible, directly noticeable consequences, as Mintz says, questions of “long-term nutritive or medical consequences went unasked and unanswered.” Most of us today will never know if we suffer even subtle withdrawal symptoms from sugar, because we’ll never go long enough without sugar to find out.
    Mintz and other sugar historians consider the drug comparison to be so fitting in part because sugar is one of a handful of “drug foods,” to use Mintz’s term, that came out of the tropics, and on which European empires were built from the sixteenth century onward, the others being, tea, coffee, chocolate, rum, and tobacco. Its history is intimately linked to that of these other “drugs”. Rum is distilled, of course, from sugarcane, whereas tea, coffee, and chocolate were not consumed with sweeteners in their regions of origin. In the seventeenth century, however, once sugar was added as a sweetener and prices allowed it, the consumption of these substances in Europe exploded. Sugar was used to sweeten liquors and wine in Europe as early as the fourteenth century; even cannabis preparations in India and opium-based wines and syrups included sugar as a major ingredient.
    The common tendency is to think of this explosion in the use of sugar by humans,  as driven by the mere fact that sugars and sweets taste good. We can call it the “pause that refreshes” hypothesis of sugar history. The alternative way to think about this is that sugar took over our diets because the first taste, whether for an infant today or for an adult centuries ago, is literally, as Michael Pollan put it, an astonishment, a kind of intoxication; “it’s the kindling of a lifelong craving, not identical but analogous to that of other drugs of abuse”. Because it is a nutrient, and because the conspicuous results of its consumption are relatively benign compared with those of nicotine, caffeine, and alcohol—at least in the short term and in small doses—it remained, as Sidney Mintz says, nearly invulnerable to moral, ethical, or religious attacks.
    A second factor in the transformation of sugar into a dietary staple—one of life’s necessities—was technology. The industrial revolution, inaugurated by Watt’s steam engine in 1765, transformed sugar production and refining just as it did virtually every other existing industry in the nineteenth century. By the 1920s, sugar refineries were producing as much sugar in a single day—millions of pounds—as would have taken refineries in the 1820s an entire decade. With sugar becoming so cheap that everyone could afford it, the manner in which we consumed it would change as well. Not only did we add sugar to hot beverages and bake it into wheat products or spread it on top—jams and jellies were two foods that cheap, available sugar made ubiquitous, since fruit could now be preserved at the end of the growing season and provide nutrition (sweetened, of course) all year round—but the concept of a dessert course emerged for the first time in history in the mid-nineteenth century, the expectation of a serving of sweets to finish off a lunch or dinner. The industrial work break also emerged, as a new era of factory workers learned to partake of some combination of nicotine, caffeine, and sugar; cigarettes, coffee and tea, and sweetened biscuits or candy could all be purchased inexpensively.
    

      Lastly, it is worth mentioning how sugar and sweets became, after thousands years of use, a synonymous to love and affection and the language with which we communicate them—“sweets,” “sweetie,” “sweetheart,” “sweetie pie,” “honey,” “honeybun,” “sugar,” and all manner of combinations and variations. Sugar and sweets became a primary contribution to our celebrations of holidays and accomplishments, both major and minor. For some people sugar and sweets have become the tools they used to reward their children’s accomplishments, to demonstrate the love and pride in them, to motivate them, to entice them. Sweets have become the currency of childhood and parenting.
    

 

References

Taubes G. (2017); “The case against sugar” , Alfred A. Knopf, New York,.

Mintz, S. W. (1991) ; “Pleasure, Profit, and Satiation.” In Seeds of Change, ed. J. J. Viola and C. Margolis (Washington, D.C.: Smithsonian Institution).

Mintz, S. W. (1985) ; Sweetness and Power: The Place of Sugar in Modern History. New York: Penguin.

Pollan, M.  (2008);  In Defense of Food. New York: Penguin.

Pollan, M. (2002) ; “When a Crop Becomes King.” New York Times Magazine, July 19: A17.

Pollan, M. (2001) ; The Botany of Desire: A Plant’s-Eye View of the World. New York: Random House.

Ferguson, N. (2002) ; Empire: The Rise and Demise of the British World Order and the Lessons for Global Power. London: Penguin.

Twain, M. (2010);  Autobiography of Mark Twain: The Complete and Authoritative Edition. Vol. 1. Berkeley: University of California Press.

Sugar Research Foundation, Inc (SRF). (1945) ;  Some Facts About the Sugar Research Foundation, Inc., and Its Prize Award Program. Oct. Washington: Sugar Research Foundation, Inc.

Sugar Association, Inc. (SAI). (1978);  Sugar Association, Inc., winter meeting of the board of directors, Chicago, Ill., Feb. 9, 1978. Research projects report, Washington, D.C. Sugar Association, Inc., Records of the Great Western Sugar Company, Colorado Agricultural Archive, Colorado State
University.

Prinsen Geerligs, H. C. (2010);  The World’s Cane Sugar Industry, Past and Present. Cambridge, U.K.: Cambridge University Press. [Originally published in 1912.]

 

How to incorporate the practice of fasting in our everyday life

 

     As we saw in the first part , fasting is the voluntary avoidance of food for health, spiritual, or other reasons. It’s done by someone who is not underweight and has enough stored body fat to live off. When done correctly, fasting should not cause suffering, and certainly never death. Food is easily available, but you choose not to eat it. This can be for any period of time, from a few hours up to a few days or – with medical supervision – even a week or more. You may begin a fast at any time of your choosing, and you may end a fast at will too.

So, in theory,  anytime we are not eating ,we are intermittently fasting. But let’s dive into the science behind it.

    Intermittent fasting (IF) covers a broad class of dietary interventions that alternate periods of eating and extended fasting on recurring basis. IF interventions can include periodic 24-hour fasts, intermittent energy restriction (e.g., the 5:2 protocol), and time-restricted eating (TRE). Our bodies need a 24 hour continual source of energy just for the basic metabolic housekeeping – keeping the heart pumping blood, liver and kidney functions, the lungs sucking air, brain function etc. Since we do not eat food all the time, we have a system of storing food energy (in the liver and as body fat) for times where we are not eating, like when we are sleeping for example.  At moments like these , our body needs to pull some of the food energy we’ve stored away to keep our vital organs running. This is the reason we do not die in our sleep every single night.
   So, it becomes obvious that IF is not something unusual but a part of everyday, normal life. Yet somehow we have missed its power and overlooked its therapeutic potential. For example, you may be already intermittently fasting every day , between the dinner and the breakfast of the next day, a period that for most people is approximately 10 hours. Although the main benefits of IF start to appear after 12 hours of not ingesting any food, the 10 hours you stayed without feeding your self still count as IF. Just consider the term “breakfast.” It refers to the meal that breaks your fast – which is done daily in the morning. In that sense, even the English language implicitly acknowledges that fasting should be considered a part of everyday life.
    As we saw in the first part of this series,  at its very core, fasting simply allows the body to use its stored sources of energy – blood sugar and body fat. This is an entirely normal process and humans have evolved these storage forms of food energy precisely so that we can fast for hours or days without detrimental health consequences. Blood sugar and body fat is merely stored food energy ready to fuel the body when food is not available. By fasting, we are lowering blood sugar and body fat by using them precisely for the reason we store them. So, if we need to restore balance in our dietary patterns , if we need to achieve metabolic flexibility or if we need to lose weight, we may simply need to increase the amount of time spent burning food energy.

That’s intermittent fasting.

Intermittent fasting benefits

IF’s most obvious benefit is weight loss. However, there are many potential benefits beyond this, some of which have been known since ancient times.  The fasting periods were often called ‘cleanses,’ ‘detoxifications’ or ‘purifications,’ but the idea is similar – to abstain from eating food for a certain period of time. People believed that this period of abstinence from food would clear their systems of toxins and rejuvenate them. Since we talked excessively about the benefits of fasting in general in the first part of this series, in this post i will just mention the most important benefits of IF reported through scientific research :

• Weight and body fat loss - improved body composition.
• Lowered blood insulin and sugar levels
• Lowered blood insulin and glucose levels - Reversal of type 2 diabetes
• Reduced hemoglobin A1c (A1c) levels
• Improved mental clarity and concentration
• Increased energy
• Increased growth hormone, at least in the short term
• Improved blood cholesterol profile
• Increased longevity
• Activated cellular cleansing by stimulating autophagy
• Reduction of inflammation

 

How can we apply in our everyday life the practice of IF?  Here, i am presenting some of the most important protocols.

Protocols

 

    1.  Time-restricted eating (12:12 fasting, 14:10 - 16:8 fasting, 18:6 fasting, and 20:4 fasting)

    While IF, is a term used to describe a lot of different protocols, it’s most often used to describe something called Time Restricted Eating (TRE)—meaning, restricting the period of time you eat to a set number of hours each day. Time restricted eating, also called time restricted feeding (TRF) in research settings, typically consists of confining all your eating to a 12-hour, 10-hour, 8-hour, 6-hour, or 4-hour window, and fasting the remainder of the day. Lets see them analytically :

• 12-hour fasting

Many experts view a 12-hour eating/12-hour fasting window (think: eating breakfast at 8 a.m. and wrapping up dinner by 8 p.m.) as a great, safe place to start for anyone. It shouldn’t be that difficult , since one can fit the 8 hours of sleep in the 12 hour fasting window, therefore the challenge here is to remain without food for 4 more hours.  Piece of cake !

• 14:10 and 16:8 fasting

Some of the most popular versions of TRE are the 14:10 or 16:8 fasting plans, which consist of a daily 14-hour and 16-hour fast while confining your eating to an 10-hour and 8-hour window respectively. If you can't live without breakfast, slot your food earlier in the day (8 a.m. to 6 pm or 4 p.m.). If you prefer an early dinner, eat in the middle of the day (11 a.m. to 9 pm or 7 p.m.). If you're someone who regularly goes out with friends for late dinners, schedule your eating hours later in the day (1 pm to 11pm or 9 pm).

• 18:6 fasting

Also popular, but a bit more intense, is the 18:6 fasting plan, which is a daily 18-hour fast where you confined your eating to a 6-hour window. If your goal is weight loss and you’ve experienced a plateau on a 16:8 plan, this is the logical next step. While more research is needed, an 18:6 fast likely helps your body burn stored carbohydrates (glycogen) faster so you can start burning fat (in the form of ketones) for fuel, and some believe it may be enough to activate autophagy—a cellular clean-up process that’s associated with longevity.

• 20:4 fasting

The most restrictive of the popular TRE regimens is the 20:4 fast (sometimes called the “warrior diet”), which is a daily 20-hour fast where you confined your eating to a 4-hour window. This essentially breaks down to one meal a day and is not for beginners—you need to work your way up. Compared to a 16:8 or 18:6 fast, it’s speculated that you will burn more fat, lose more weight, and experience greater autophagy on a 20:4 diet, since the fasting hours last for almost all day.

 

       2.  Alternate-day fasting (36 hour fast)

      Also under the umbrella of intermittent fasting is alternate-day fasting (ADF). ADF is just how it sounds: You only eat every other day. So, practically,  you fast for 36 hours on a recurring basis. You finish dinner on day 1 at 7 pm for instance, and you would skip all meals on day 2, and not eat again until breakfast at 7 am on day 3. So that is a total of 36 hours of fasting followed by an 12-hour eating window. While some purists only consume water, herbal tea, and moderate amounts of black coffee on fasting days, others employ the 25 percent rule. In this version, you consume 25 percent of your normal caloric intake on fast days. This protocol has shown really good results for weight loss and reducing inflammation and while many clinics often recommend 36-hours fasts 2-3 times per week for reversing type 2 diabetes, alternate-day fasting is a more extreme approach to IF that may be hard to sustain over the long term. For obvious reasons, is not for beginners, and it should be reserved for specific medical cases.

 

    3.   5:2 plan

    A slightly easier variation of ADF, the 5:2 plan allows you to eat normally for five days every week while eating only 500 to 600 calories on the other two days. You can choose whichever two days of the week you prefer, as long as there is at least one non-fasting day in between them. One common way of planning the week on this protocol , is to fast on Mondays and Thursdays, with two or three small meals, then eat normally for the rest of the week. It’s important to emphasize that eating “normally” does not mean you can eat anything. If you binge on junk food, then you probably won’t lose any weight, and you may even gain weight.

 

Where to place your TRE window?

     The ideal placement of your eating and fasting window will likely depend on a number of factors—work schedule, social obligations, fitness routine, and simply what feels best for your body—but a growing body of research seems to suggest that an earlier eating window may be better. A small but rigorously controlled randomised crossover study from 2019 found that when participants ate between 8 a.m. and 2 p.m., they fared much better than when they ate the same three meals on an 2 p.m. to 8 p.m. schedule.  Moreover , they had lower blood glucose levels during the day and overnight, lower insulin levels, and an ideal cortisol pattern (with levels higher in the morning and lower at night)—all of which suggests an improvement in circadian rhythm. More surprisingly, though, was that after just four days, this earlier eating schedule increased the expression of the SIRT1 gene (associated with longevity and healthy aging) and the LC3A gene (a biomarker of autophagy).

 

 

How do you manage hunger?

   The million dollar question! “If i am hungry in only 3 hours after eating , how will i be able to fast for many more hours?” … Hunger is not so simple as your stomach being ’empty’. Hunger is, in fact, a highly susceptible state with a complex hormonal regulation at play. In essence, there are two major components to hunger: The unconditioned biological stimuli – that is, the part that will normally stimulate hunger naturally (smells, sights, and tastes of food) and the conditioned stimuli (learned – movie, lecture, morning etc). These conditioned responses can be very powerful and cause great hunger. If for example we consistently eat breakfast every single morning at 7:00am, lunch at 12:00 and dinner at 6:00pm, then the time of the day itself becomes a conditioned stimulus for eating. Even if we ate a huge meal at dinner the night before, and would not otherwise be hungry in the morning, we may become ‘hungry’ because it is 7:00am. The Conditioned Stimulus (time of 7:00) causes the Conditioned Response (hunger). How to combat this? Well, intermittent fasting offers a unique solution. By skipping meals and varying the intervals that we eat, we can break our current habit of feeding 3 times a day. We no longer have a conditioned response of hunger every 3-5 hours.
    And what about the hunger we feel by the unconditioned biological stimuli during our day? The most important thing to realise is, that this type of hunger, usually passes like a wave. It comes and it goes. That is, we may not be hungry one second, but after smelling a steak and hearing the sizzle, we may become quite ravenous. And then, we may engage in an activity and we forget after some minutes completely the steak and our hunger .  Many people worry that hunger during IF will continue to build up until it is intolerable, but this does not normally happen. Approximately 3-6 hours after we eat a meal, we start to feel hunger pangs and may become slightly cranky. But if we simply ignore it and drink a cup of tea or coffee, or we keep ourselves busy with activities , it will often pass.

 

References

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Anton SD, Moehl K, Donahoo WT, et al. Flipping the Metabolic Switch: Understanding and Applying the Health Benefits of Fasting. Obesity (Silver Spring). 2018;26(2):254-268. doi:10.1002/oby.22065

 

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Kahleova H, Belinova L, Malinska H, Oliyarnyk O, Trnovska J, Skop V, Kazdova L, Dezortova M, Hajek M, Tura A, Hill M, Pelikanova T. Eating two larger meals a day (breakfast and lunch) is more effective than six smaller meals in a reduced-energy regimen for patients with type 2 diabetes: a randomised crossover study. Diabetologia. 2014 Aug;57(8):1552-60. doi: 10.1007/s00125-014-3253-5. Epub 2014 May 18. Erratum in: Diabetologia. 2015 Jan;58(1):205.

 

Jamshed, H., Beyl, R. A., Della Manna, D. L., Yang, E. S., Ravussin, E., & Peterson, C. M. (2019). Early Time-Restricted Feeding Improves 24-Hour Glucose Levels and Affects Markers of the Circadian Clock, Aging, and Autophagy in Humans. Nutrients, 11(6), 1234. https://doi.org/10.3390/nu11061234.

 

Varady, K. A., Bhutani, S., Klempel, M. C., Kroeger, C. M., Trepanowski, J. F., Haus, J. M., Hoddy, K. K., & Calvo, Y. (2013). Alternate day fasting for weight loss in normal weight and overweight subjects: a randomized controlled trial. Nutrition journal, 12(1), 146.

Johnstone AM, Faber P, Gibney ER, Elia M, Horgan G, Golden BE, Stubbs RJ. Effect of an acute fast on energy compensation and feeding behaviour in lean men and women. Int J Obes Relat Metab Disord. 2002 Dec;26(12):1623-8.

Johnstone AM, Faber P, Gibney ER, Elia M, Horgan G, Golden BE, Stubbs RJ. Effect of an acute fast on energy compensation and feeding behaviour in lean men and women. Int J Obes Relat Metab Disord. 2002 Dec;26(12):1623-8. doi: 10.1038/sj.ijo.0802151. PMID: 12461679.