Rest for the Body, the Digestive System, and the Mouth

Rest is a biological necessity, not simply a period when nothing is happening. During sleep, the body carries out processes involved in tissue repair, immune regulation, hormone regulation, memory, and recovery. Rest also occurs between periods of eating. The digestive system has distinct fed and fasting states, and the mouth needs time between repeated food exposures for saliva to neutralize acids and help protect the teeth.¹,²,³ The principle of REST therefore includes more than sleep. It includes giving the body appropriate periods for recovery and allowing the digestive system and oral environment to complete their normal cycles.

1. Sleep Is Active Restoration

Sleep may look like inactivity, but the sleeping body remains biologically active. Brain activity changes, hormones follow daily patterns, immune processes continue, and tissues undergo repair and maintenance. Adequate sleep is associated with better physical and mental health, while chronic sleep deficiency is associated with numerous adverse health outcomes. The American Academy of Sleep Medicine and Sleep Research Society recommend that adults obtain 7 or more hours of sleep per night on a regular basis for optimal health.⁴

Sleep also matters to the mouth. A 2024 scoping review examining the relationship between sleep and oral health found evidence connecting sleep duration or quality with several oral conditions. Among the studies reviewed, shorter sleep was associated with increased risk of periodontitis in adults, while sleep was also associated with dental caries in children. The authors emphasized that more research is needed to understand the mechanisms and the strength of these relationships.⁵

Healthy sleep does not eliminate dental plaque, replace brushing, or replace cleaning between the teeth. Rather, sleep is part of the biological environment in which the mouth must defend itself, regulate inflammation, and repair tissues.

2. The First Part of the Night Is Especially Important

Sleep is organized into repeating cycles rather than being one uniform state. The proportion of deep, slow-wave sleep is generally greatest during the first part of the biological night, while REM sleep becomes more prominent later in the sleep period.⁶,⁷ This is one reason that obtaining sufficient sleep at an appropriate biological time matters rather than simply counting hours.

The period between approximately 9 PM and 2 AM is often described in health education as a particularly valuable window for regenerative sleep. The scientific evidence supports the broader principle behind this teaching: early-night sleep normally contains a greater proportion of slow-wave sleep, which is associated with important restorative processes.⁶,⁷ However, 9 PM to 2 AM should not be presented as a universal biological cutoff that applies identically to every person. Individual circadian timing varies, and the timing of the first part of biological night depends on the person's sleep-wake schedule and internal clock.

For practical health education, the principle is simple: do not routinely sacrifice the early part of the night's sleep period. A regular bedtime that provides enough total sleep allows the body to obtain the deep sleep that normally occurs earlier in the sleep episode.

3. Regular Sleep and Wake Times Help Establish a Rhythm

The human body contains a circadian timing system that coordinates daily patterns in sleep, hormones, body temperature, metabolism, and other functions. Light is the strongest environmental signal for the central circadian clock, but eating, physical activity, and other daily behaviors provide additional timing signals.⁸,⁹

Regularity matters because the body does not simply respond to the clock on the wall. It develops predictable biological patterns based on repeated environmental cues. A consistent sleep and wake schedule helps reinforce the timing of the sleep-wake cycle. Conversely, constantly changing sleep times can make it more difficult for the biological clock and daily behavior to remain aligned.

This same principle becomes especially important when considering meal timing.

4. The Digestive System Has Its Own Rhythms

The digestive tract is not simply a container that waits for food. The stomach, intestines, liver, pancreas, and other digestive tissues contain biological clocks and show daily rhythms in secretion, motility, absorption, hormone activity, metabolism, and other functions.⁸,⁹,¹⁰

The central circadian clock is strongly influenced by the light-dark cycle. Peripheral clocks throughout the body can also respond to feeding schedules. Research demonstrates that the timing of food can synchronize peripheral circadian rhythms, particularly in tissues involved in digestion and metabolism.¹⁰,¹¹

This means that meal timing is not biologically irrelevant. The body receives information not only from what is eaten, but also from when food is regularly introduced.

5. The Body Can Learn the Timing of Meals

One of the most interesting findings in digestive physiology is that the body can begin preparing for food before food actually reaches the stomach.

The digestive system has several mechanisms that allow it to anticipate an expected meal. Research on food-anticipatory responses shows that repeated feeding schedules can produce physiological changes before food is consumed. These responses can involve hormones, metabolism, appetite, and digestive activity.¹¹,¹²,¹³

This is important because hunger that appears at approximately the same time each day does not necessarily require a person to be looking at food, smelling food, discussing food, or even thinking about food. When meals are regularly scheduled, the body can learn the pattern. Researchers have observed anticipatory physiological responses associated with predictable meal timing in both animal and human research.¹¹,¹³

Food-related sights, smells, tastes, and thoughts can certainly stimulate digestive responses through the cephalic phase of digestion, but these are not the only mechanisms involved. The body's biological clocks and learned associations with regular meal times can contribute to predictable digestive rhythms as well.¹²,¹⁴

The practical principle is straightforward: when meals occur at predictable times, the body can learn that pattern and begin preparing for food before the meal begins.

6. Regular Meals Can Create Food-Anticipatory Responses

Researchers have studied what happens when food is provided at predictable times. The resulting phenomenon is called a food-anticipatory response.

A systematic review of human and animal research identified numerous studies showing hormonal and metabolic responses associated with predictable feeding. In human studies, researchers observed anticipatory changes associated with feeding schedules and other signals connected with eating.¹³

Experimental research also demonstrates that peripheral organs—including the stomach, intestines, liver, and pancreas—can respond to regular feeding schedules. Daily feeding patterns can shift the timing of circadian activity in these organs.¹¹

The practical lesson is important: regular meal timing gives the digestive system a predictable pattern to work with. The body can prepare for eating, process the meal, and then enter a period in which no new food is being introduced.

This is one reason a regular rhythm of waking, sleeping, and eating makes biological sense.

7. The Stomach Prepares for Food

The stomach does not simply wait until food arrives and then suddenly begin working. Gastric secretion and motility can begin responding during the cephalic phase of digestion. Anticipation of a meal can stimulate gastric secretions before ingestion.¹²,¹⁴

Regular meal timing can therefore become one of the signals that helps coordinate digestive activity. This does not mean that the stomach has a clock that mechanically releases exactly the same amount of acid at exactly the same minute every day. Rather, the nervous system, circadian system, learned meal timing, and digestive organs interact to create predictable physiological responses.

A regular meal pattern therefore gives the digestive system a predictable rhythm: preparation, eating, digestion, emptying, and a period between meals.

8. Saliva Also Has a Biological Rhythm

The mouth participates in the digestive process before food reaches the stomach. Saliva moistens food, begins digestion of certain components, assists swallowing, protects oral tissues, and helps maintain the chemical environment surrounding the teeth.

Salivary secretion and salivary composition also vary according to biological rhythms. One particularly interesting human study examined salivary carbonic anhydrase VI (CA VI), an enzyme produced by the salivary glands. Six healthy men were studied over a 24-hour period while following a regular sleep schedule and regular meals at 7:30 AM, 1:30 PM, and 7:30 PM. CA VI and amylase activity followed marked daily patterns, declining to very low levels during sleep. The researchers concluded that CA VI secretion follows a circadian rhythm that is related to, but not simply explained by, the amount of saliva being secreted.¹⁵

This provides direct evidence that salivary physiology follows biological timing.

CA VI is a carbonic anhydrase enzyme involved in the bicarbonate-related chemistry of saliva. It is associated with the ability of saliva to regulate acidity in the mouth. This does not mean that CA VI is a digestive enzyme responsible for breaking down a meal in the way that salivary amylase begins carbohydrate digestion. Its importance is better understood as part of the chemical environment maintained by saliva.¹⁵

The finding is nevertheless significant for the REST principle because it demonstrates that the mouth itself participates in daily biological rhythms. The salivary glands are not simply producing exactly the same secretion around the clock.

9. The Stomach Needs Time to Empty

After a meal, the stomach must process its contents and gradually release them into the small intestine. Gastric emptying is influenced by the size and composition of the meal and by the physiological state of the digestive tract.¹⁶

This is important when considering continual eating.

The stomach does not necessarily become completely empty before every subsequent meal, and there is no scientifically established universal number of hours that every person must wait between all meals. However, repeatedly introducing food changes the normal pattern of gastrointestinal activity and can prolong the fed state.

Research has directly examined frequent feeding. In a controlled human study, frequent feeding before a subsequent meal delayed gastric emptying of that subsequent meal compared with less frequent feeding.¹⁷

The important lesson is therefore not that every additional bite causes the previous meal to remain in the stomach for a specific number of hours. The evidence supports a more precise conclusion:

The digestive system needs time to process and empty food, and repeatedly adding food changes the normal timing of that process.

10. The Digestive Tract Has a Fasting State

Between meals, the stomach and small intestine do not simply become inactive. During fasting, they enter a recurring pattern of contractions known as the migrating motor complex, or MMC.

The MMC occurs during the fasting state and is interrupted when food is consumed. One of its functions appears to be moving residual material through the upper gastrointestinal tract. Because of this function, it has sometimes been described as a type of gastrointestinal "housekeeping" activity.¹⁸,¹⁹

The distinction between the fed and fasting states is important. During eating and digestion, the gastrointestinal tract is processing incoming food. Between meals, the digestive system can return to its fasting motor pattern. Continual eating repeatedly interrupts that fasting pattern.¹⁸,¹⁹

This gives biological meaning to the concept of rest for the stomach.

11. Rest for the Stomach Does Not Mean Starvation

Rest for the digestive system should not be confused with extreme fasting or inadequate nutrition. The principle is much simpler: eat nourishing meals, then allow a reasonable period without continually adding more food.

There is no strong scientific basis for declaring that every adult must eat exactly twice or exactly three times per day. Energy needs differ among individuals, and meal patterns vary with age, activity, pregnancy, medications, work schedules, and other circumstances.

The evidence does support discouraging continual grazing—eating small amounts repeatedly from morning until night without meaningful periods between eating occasions. Regular meal timing gives the digestive system predictable periods of feeding and fasting and gives the mouth periods without repeated food

exposure.

12. Snacking Has an Important Oral-Health Cost

The oral-health consequences of frequent eating are especially important. Dental plaque contains bacteria that can metabolize fermentable carbohydrates and produce acids. These acids lower the pH at the tooth surface and contribute to enamel demineralization. Saliva then works to neutralize the acids and helps restore minerals to the enamel.²⁰,²¹

Every new exposure to fermentable carbohydrate can create another acid challenge. The problem is therefore not simply the total amount of sugar eaten. Frequency matters. Repeated exposure can produce repeated periods of low plaque pH, giving the teeth less time to recover between attacks.²⁰

A systematic review of prospective studies found that between-meal consumption of processed sugar- and starch-containing foods was consistently associated with greater dental caries experience among the studies included.²²

This provides a strong oral-health reason to discourage unnecessary snacking.

13. Let the Mouth Rest Between Meals

When a meal ends, the oral environment does not immediately return to its resting state. Saliva begins neutralizing acids and helping restore the mineral balance at the tooth surface. The length of this recovery period depends on what was eaten, how it was consumed, salivary flow, plaque conditions, and other factors.²⁰,²¹

When another sugary or fermentable food is eaten soon afterward, another acid-producing episode can begin. This creates a repeated cycle:

Food exposure → bacterial fermentation → acid production → enamel demineralization → salivary recovery

If food is continually introduced, the cycle is continually restarted. This is why the REST principle applies to the mouth as well as the stomach. The mouth needs periods without repeated food exposure.

14. Rest and Oral Cleanliness Work Together

A person who brushes carefully and then continually eats throughout the day repeatedly reintroduces nutrients that oral bacteria can use. The greatest concern is repeated exposure to sugars and other fermentable carbohydrates, particularly between meals and close to bedtime.²⁰,²²

A structured meal pattern therefore has two advantages. It allows the digestive system periods in which no new food is being introduced, and it gives the mouth longer periods in which saliva can maintain and restore the oral environment.

Good oral hygiene remains essential. Rest between meals does not replace brushing, cleaning between the teeth, fluoride where appropriate, or professional dental care.

15. Regular Meal Timing Is Different From Constant Eating

Regularity does not mean eating every time the clock suggests food. The evidence points toward a different concept: predictable eating periods separated by periods without food.

When meals are consistently timed, the body can develop anticipatory responses to those meals.¹³ When eating continues throughout the day, the distinction between feeding and fasting becomes less clear.

This is particularly relevant at night. The circadian system normally coordinates the body toward activity and food intake during the biological day and toward sleep and fasting during the biological night.¹⁰,²³ Eating around the clock can therefore create a mismatch between the timing of food intake and the body's normal circadian organization.

16. Nighttime Eating and Circadian Biology

The body's internal clocks do not operate independently of behavior. The central circadian system is strongly synchronized by light, while meal timing is an important signal for peripheral clocks.²³,²⁴

Research on meal timing has found that eating at biologically unusual times can alter metabolic processes. Shift workers are a particularly important example because their work schedules can require nighttime wakefulness, daytime sleep, and eating at times that conflict with the usual light-dark cycle.²⁵

This does not mean that every person who eats late at night will develop disease. It does mean that the timing of food is biologically relevant and that habitual nighttime eating should not be considered equivalent to daytime eating simply because the calories are the same.

For the REST principle, a practical message is appropriate: give the digestive system a period of rest during the night rather than continuing to eat simply because food is available.

17. Shift Work Creates a Special Challenge

Not everyone can follow a conventional daytime schedule. Some people must work during the night, sleep during the day, or maintain changing schedules.

Shift work can disrupt the normal relationship among light exposure, sleep, wakefulness, and meal timing. Reviews of shift work describe this as circadian misalignment and associate it with metabolic disturbances and increased cardiometabolic risk.²⁵

The goal for a shift worker is not to pretend that a conventional daytime schedule is possible. Instead, the principle is to create as much regularity and protected sleep as the person's circumstances allow and to avoid unnecessary eating throughout the entire waking period.

The body benefits from predictable rhythms even when the schedule itself differs from the conventional day.

18. Technology and Evening Light Can Interfere With Rest

Modern technology has changed the environment in which people sleep. Bright artificial light at night can affect circadian timing, and evening exposure to light can delay melatonin rhythms and other biological markers of the internal clock.²⁶

Electronic devices may contribute through several pathways, including light exposure, stimulating content, notifications, and delayed bedtime. A systematic review of experimental studies found that evening light exposure can produce phase delays in melatonin and other circadian measures.²⁶

For practical purposes, the goal is not to create fear around phones or computers. It is to protect the transition from daytime activity to nighttime rest by reducing unnecessary bright light and stimulating technology close to bedtime.

19. Healthy Sleep Habits Protect the Period of Rest

A healthy sleep routine begins before the head reaches the pillow. A reasonably consistent sleep and wake schedule, adequate time allotted for sleep, a dark and comfortable sleeping environment, and reduced stimulation before bedtime can all support healthy sleep.

Sleep hygiene by itself is not considered sufficient treatment for chronic insomnia, but these habits can form part of a broader approach to healthy sleep.²⁷

Helpful practices include:

Keep sleep and wake times reasonably consistent.

Allow enough time to obtain adequate sleep.

Keep the bedroom dark, quiet, and comfortable.

Reduce bright light and stimulating technology before bed.

Avoid routinely carrying work and other stimulating activities into the sleeping period.

Avoid making late-night eating a regular habit.

Seek evaluation when persistent snoring, witnessed pauses in breathing, severe daytime sleepiness, or other signs of sleep-disordered breathing occur.

The objective is not perfection. The objective is to establish a predictable period in which the body can enter sleep and remain there long enough to obtain its normal restorative processes.

20. Rest, Bruxism, and the Teeth

Bruxism refers to repetitive jaw-muscle activity that may include clenching, grinding, or bracing the jaw. It can occur while awake or during sleep.

Sleep-related bruxism is not simply a matter of "being stressed." Current evidence indicates that sleep bruxism is a complex behavior involving the nervous system and sleep-related arousal activity.²⁸,²⁹

Persistent or forceful bruxism can contribute to tooth wear, muscle discomfort, jaw pain, headaches, and stress on dental restorations. However, tooth wear alone does not prove that a person has bruxism; a 2024 scoping review found that the relationship between bruxism and tooth wear remains more complicated than it is sometimes presented.³⁰

This distinction matters. A person should not be told that every worn tooth is proof of nighttime grinding.

21. Awake Clenching Is Another Form of Jaw Overuse

Some people clench their teeth or brace their jaw muscles while awake, especially during concentration or demanding activities. The teeth do not normally need to remain together throughout the day.

A useful resting position is:

Lips gently together

Teeth slightly apart

Jaw muscles relaxed

Tongue resting comfortably against the palate

The goal is not to hold the jaw rigidly in one position. The goal is to recognize unnecessary tooth contact and muscle tension and allow the muscles to relax when chewing and speaking are not required.

Reducing unnecessary daytime clenching can decrease the amount of repeated loading placed on the teeth and jaw muscles.

22. Sleep Disorders Can Affect the Mouth

Sleep and oral health can intersect through sleep-disordered breathing. Obstructive sleep apnea (OSA) occurs when the upper airway repeatedly becomes narrowed or blocked during sleep. These episodes can interrupt normal sleep and may cause repeated drops in blood oxygen.

OSA has important oral-health connections. Recent systematic reviews and umbrella reviews have found an association between OSA and periodontitis, although the available evidence is predominantly observational and does not establish that OSA directly causes periodontal disease.³¹,³²

Sleep-related breathing disorders may also occur alongside mouth breathing, dry mouth, bruxism, and other oral findings.

Persistent snoring, witnessed pauses in breathing, gasping during sleep, excessive daytime sleepiness, morning dry mouth, or other concerning sleep-related symptoms deserve attention rather than being dismissed as simply "poor sleep."

23. CPAP Can Restore Breathing During Sleep

For people diagnosed with obstructive sleep apnea, continuous positive airway pressure (CPAP) is an important treatment. CPAP delivers air through a mask to help keep the airway open during sleep.

When used appropriately, CPAP can reduce obstructive breathing events and improve oxygenation. It can therefore help restore a more normal sleep environment for a person whose airway repeatedly collapses during sleep.³³

CPAP equipment can also affect the mouth. Some users experience dry mouth, particularly when mouth breathing or mask leakage occurs. Good oral hygiene and appropriate management of dryness are therefore important parts of maintaining oral health while using CPAP.

CPAP should not be viewed as a failure of the body. It is a treatment that helps restore airflow when the airway is not remaining open adequately during sleep.

24. Oral Appliance Therapy Can Help Selected Adults With OSA

Some adults with obstructive sleep apnea use a custom oral appliance designed to help maintain airway openness during sleep. Mandibular advancement appliances hold the lower jaw in a forward position and can reduce airway obstruction in appropriately selected patients.³⁴

Clinical guidelines recommend consideration of oral appliance therapy for adults with OSA who are intolerant of CPAP or prefer an alternative treatment. When an oral appliance is selected, the guideline recommends a custom, titratable appliance rather than a non-custom device.³⁴

CPAP generally produces greater reductions in apnea-related breathing events and improvements in oxygenation, but some people tolerate oral appliances better and therefore use them more consistently.³⁴ Because oral appliances can produce dental and jaw-related effects, including tooth discomfort, muscle pain, changes in bite, and changes in salivation or dry mouth, appropriate follow-up is important.³⁵

25. Children Need Rest—and Their Sleep Problems Matter

Children require more sleep than adults, and healthy sleep is especially important during periods of growth and development.

Children can also develop obstructive sleep apnea. Enlarged tonsils and adenoids are important causes of childhood OSA, and symptoms may include habitual snoring, restless sleep, mouth breathing, unusual sleeping positions, daytime behavioral problems, or excessive sleepiness.³⁶,³⁷

The American Academy of Pediatrics recommends that children be screened for snoring and evaluated when symptoms suggest obstructive sleep apnea. For many otherwise healthy children with enlarged tonsils and adenoids, adenotonsillectomy is an important treatment; CPAP is another option when surgery is not appropriate or when OSA remains after surgery.³⁶,³⁷

Children should not be expected to simply "outgrow" persistent breathing problems during sleep without evaluation.

26. Rest Helps Break the Cycle of Jaw Tension and Poor Sleep

Jaw tension and poor sleep can reinforce one another. Pain or discomfort may interfere with sleep, while inadequate sleep can increase pain sensitivity and reduce the ability to cope with physical and emotional demands. Sleep-related bruxism may add another source of mechanical stress to the teeth and jaw.

Persistent jaw pain, significant tooth damage, suspected sleep bruxism, or symptoms of sleep-disordered breathing may require evaluation. Conservative approaches may include awareness of daytime clenching, jaw-rest strategies, appropriate exercises, physical therapy, management of sleep disorders, and selected dental appliances. In carefully selected situations, other treatments may be considered.

Rest is therefore not a substitute for appropriate care. It is one part of creating the biological conditions in which the muscles, joints, teeth, and supporting tissues can recover.

27. Rest Is a Pattern, Not a Single Event

The principle of REST becomes clearer when these systems are viewed together. The body has periods of activity and recovery. The brain cycles between wakefulness and sleep. The digestive tract cycles between fed and fasting states. The stomach digests and empties, then returns to its fasting motor pattern. The salivary glands follow biological rhythms, and the mouth experiences food exposure followed by periods in which saliva can neutralize acids and restore the oral environment. The jaw muscles work during chewing and speaking and should have periods of relaxation.

These are not isolated processes. They are coordinated biological rhythms.

28. God's Design Includes Periods of Activity and Restoration

The biblical pattern of rest provides a meaningful framework for understanding these biological principles. Scripture presents a rhythm that includes work and rest, activity and restoration.

Genesis describes God completing His work and then resting from His work. The Sabbath command later establishes a recurring rhythm of labor followed by rest: "Six days shalt thou labour, and do all thy work: But the seventh day is the sabbath of the LORD thy God."³⁸

Rest, therefore, is not presented as laziness or wasted time. It is part of an ordered pattern.

The same principle can be observed throughout human physiology. The body is designed to work, recover, rebuild, and begin again. Sleep restores. Fasting periods allow the digestive tract to return to its normal between-meal pattern. Periods without food give the mouth time to recover from repeated acid challenges. Muscles require relaxation after work.

God's design includes both activity and restoration.

29. The REST Principle

Healthy rest means more than getting through the day until bedtime. It means respecting the body's need for rhythm, recovery, and restoration.

For the mouth and digestive system, this includes eating nourishing meals rather than continually grazing, allowing reasonable periods between eating occasions, limiting repeated exposure to sugars and fermentable carbohydrates, and allowing the oral environment time to recover.

For sleep, it means protecting sufficient sleep, maintaining a reasonably regular sleep-wake rhythm, respecting the biological night, and recognizing signs that a sleep disorder may be interfering with restoration.

For the teeth and jaw, it means allowing unnecessary muscle tension to release and recognizing that persistent clenching, grinding, pain, or sleep-disordered breathing deserves appropriate attention.

Rest is not the absence of biological activity. Rest is part of the body's activity. It is the period in which the body restores, regulates, repairs, and prepares for what comes next.

Footnotes and References

1. Deloose, E., Janssen, P., Depoortere, I., & Tack, J. (2012). The migrating motor complex: Control mechanisms and its role in health and disease. Nature Reviews Gastroenterology & Hepatology, 9, 271–285.
2. Hall, J. E. (2021). Guyton and Hall textbook of medical physiology (14th ed.). Elsevier.
3. Moynihan, P., & Kelly, S. (2014). Effect on caries of restricting sugars intake: Systematic review to inform WHO guidelines. Journal of Dental Research, 93(1), 8–18.
4. Watson, N. F., Badr, M. S., Belenky, G., et al. (2015). Recommended amount of sleep for a healthy adult: A joint consensus recommendation of the American Academy of Sleep Medicine and Sleep Research Society. Sleep, 38(6), 843–844.
5. Sethi, S., et al. (2024). Effect of sleep on oral health: A scoping review. Sleep Medicine Reviews, 76, 101939.
6. Carskadon, M. A., & Dement, W. C. (2017). Normal human sleep: An overview. In M. H. Kryger, T. Roth, & W. C. Dement (Eds.), Principles and practice of sleep medicine. Elsevier.
7. Dijk, D. J., & Czeisler, C. A. (1995). Contribution of the circadian pacemaker and the sleep homeostat to sleep propensity, sleep structure, electroencephalographic slow waves, and sleep spindle activity in humans. Journal of Neuroscience, 15(5), 3526–3538.
8. Mukherji, A., Kobiita, A., & Chambon, P. (2020). Circadian rhythms in gastrointestinal physiology and disease. Nature Reviews Gastroenterology & Hepatology, 17, 239–251.
9. Voigt, R. M., Forsyth, C. B., & Keshavarzian, A. (2019). Circadian rhythms and the gut microbiome. Current Opinion in Gastroenterology, 35(6), 555–563.
10. Segers, A., & Depoortere, I. (2020). Circadian clocks in the digestive system. Nature Reviews Gastroenterology & Hepatology, 17, 239–251.
11. Tahara, Y., & Shibata, S. (2013). Chronobiology and nutrition. Neuroscience, 253, 78–88.
12. McLaughlin, J., & Luck, J. E. (2020). Food, eating, and the gastrointestinal tract. Physiology & Behavior.
13. Kalsbeek, A., et al. (2021). Food anticipatory hormonal responses: A systematic review. Physiology & Behavior.
14. Feldman, M., & Richardson, C. T. (1986). Role of thought, sight, smell, and taste of food in the cephalic phase of gastric acid secretion in humans. Gastroenterology, 90(2), 428–433.
15. Parkkila, S., Parkkila, A. K., & Rajaniemi, H. (1995). Circadian periodicity in salivary carbonic anhydrase VI concentration. Acta Physiologica Scandinavica, 154(2), 205–211.
16. Camilleri, M. (2006). Integrated upper gastrointestinal response to food intake. Gastroenterology, 131(2), 640–658.
17. Jackson, S. J., Leahy, F. E., Jebb, S. A., Prentice, A. M., Coward, W. A., & Bluck, L. J. (2007). Frequent feeding delays the gastric emptying of a subsequent meal. Appetite, 48(2), 199–205.
18. Deloose, E., Janssen, P., Depoortere, I., & Tack, J. (2012). The migrating motor complex: Control mechanisms and its role in health and disease. Nature Reviews Gastroenterology & Hepatology, 9, 271–285.
19. Szurszewski, J. H. (1969). A migrating electric complex of canine small intestine. American Journal of Physiology, 217(6), 1757–1763.
20. Moynihan, P., & Kelly, S. (2014). Effect on caries of restricting sugars intake: Systematic review to inform WHO guidelines. Journal of Dental Research, 93(1), 8–18.
21. Dawes, C. (2003). Estimates, from salivary analyses, of the normal daily exposure of the teeth to acids in the diet. Journal of Dental Research, 82(8), 648–652.
22. Sheiham, A., & James, W. P. T. (2015). A new understanding of the relationship between sugars, dental caries and fluoride use: Implications for limits on sugars consumption. Public Health Nutrition, 17(10), 2176–2184.
23. Stenvers, D. J., Jonkers, C. F., Fliers, E., Bisschop, P. H., & Kalsbeek, A. (2012). Nutrition and the circadian timing system. In Progress in Brain Research (Vol. 199, pp. 359–376). Elsevier.
24. Wehrens, S. M. T., et al. (2023). Human glucose rhythms and subjective hunger anticipate meal timing. Current Biology.
25. Potter, G. D. M., Skene, D. J., Arendt, J., Cade, J. E., Grant, P. J., & Hardie, L. J. (2016). Circadian rhythm and sleep disruption: Causes, metabolic consequences, and countermeasures. Endocrine Reviews, 37(6), 584–608.
26. Cyr, M., et al. (2022). The effect of evening light on circadian-related outcomes: A systematic review. Sleep Medicine Reviews, 65, 101660.
27. Edinger, J. D., Arnedt, J. T., Bertisch, S. M., et al. (2021). Behavioral and psychological treatments for chronic insomnia disorder in adults: An American Academy of Sleep Medicine clinical practice guideline. Journal of Clinical Sleep Medicine, 17(2), 255–262.
28. Lobbezoo, F., Ahlberg, J., Raphael, K., et al. (2018). International consensus on the assessment of bruxism: Report of a work in progress. Journal of Oral Rehabilitation, 45(11), 837–844.
29. Manfredini, D., Winocur, E., Guarda-Nardini, L., Paesani, D., & Lobbezoo, F. (2013). Epidemiology of bruxism in adults: A systematic review of the literature. Journal of Orofacial Pain, 27(2), 99–110.
30. Tooth wear and bruxism: A scoping review. (2024). The review found that evidence linking bruxism and tooth wear remains inconclusive and that tooth wear alone should not be used to infer bruxism.
31. Association between obstructive sleep apnea and periodontitis: A systematic umbrella review. (2026). The review found a significant association between OSA and periodontitis but rated the certainty of evidence low because of heterogeneity and publication bias.
32. Periodontal disease and obstructive sleep apnea: An umbrella review. (2026). The review found a consistent association while emphasizing that predominantly observational evidence cannot establish causality.
33. Patil, S. P., Ayappa, I. A., Caples, S. M., Kimoff, R. J., Patel, S. R., & Harrod, C. G. (2019). Treatment of adult obstructive sleep apnea with positive airway pressure: An American Academy of Sleep Medicine clinical practice guideline. Journal of Clinical Sleep Medicine, 15(2), 335–343.
34. Ramar, K., Dort, L. C., Katz, S. G., et al. (2015). Clinical practice guideline for the treatment of obstructive sleep apnea and snoring with oral appliance therapy: An update for 2015. Journal of Clinical Sleep Medicine, 11(7), 773–827.
35. Mansour, N., et al. (2024). Effect of mandibular advancement appliance use on oral and periodontal health in patients with OSA: A systematic review. Sleep and Breathing.
36. American Academy of Pediatrics. (2012). Diagnosis and management of childhood obstructive sleep apnea syndrome. Pediatrics, 130(3), e714–e755.
37. Marcus, C. L., Brooks, L. J., Draper, K. A., et al. (2012). Diagnosis and management of childhood obstructive sleep apnea syndrome. Pediatrics, 130(3), e714–e755.
38. Holy Bible, Exodus 20:9–10.