question: Why can we go to bed hungry but wake up not hungry?
comment: While asleep your body goes into a state that uses much much less food for energy,eating 1 hour before bed is not recommended for this reason. You just do not use nor does your digestive system works efficiently towards passing food. When you wake up it takes a bit of time to start your digestive system which gives you the feeling of not hungry, since it isn't moving your stomache down and out
passages: Metabolism involves two biochemical processes that occur in living organisms. The first is anabolism, which refers to the build up of molecules. The second is catabolism, the breakdown of molecules. These two processes work to regulate the amount of energy the body uses to maintain itself. During non-REM sleep, metabolic rate and brain temperature are lowered to deal with damages that may have occurred during time of wakefulness.
  
  Section::::Normal metabolism.
  
  After eating, the pancreas releases insulin. Insulin signals muscle and fat cells to absorb glucose from food. As a result, blood glucose levels return to normal.
   Section::::History.
   Section::::Treatment.
   There are two peptides in the hypothalamus that produce hunger, melanin concentrating hormone (MCH) and orexin. MCH plays a bigger role in producing hunger. In mice, MCH stimulates feeding and a mutation causing the overproduction of MCH led to overeating and obesity. Orexin plays a greater role in controlling the relationship between eating and sleeping. Other peptides in the hypothalamus that induce eating are neuropeptide Y (NPY) and agouti-related protein (AGRP).
   Binge eating is the core symptom of BED; however, not everyone who binge eats has BED. An individual may occasionally binge eat without experiencing many of the negative physical, psychological, or social effects of BED. This example may be considered an eating problem (or not), rather than a disorder. Precisely defining binge eating can be problematic, however binge eating episodes in BED are generally described as having the following potential features:
  
  BULLET::::- Eating much faster than normal, perhaps in a short space of time
  
  BULLET::::- Eating until feeling uncomfortably full
  
  BULLET::::- Eating a large amount when not hungry
   In 2018, BRI researchers contributed to a key finding about babies’ sleep patterns: Many infants sleep better – and longer – when they start eating solid foods. In the study, half the babies subsisted entirely on breast milk until six months of age, while the other half started eating solid foods at three months of age. Compared to babies who were solely breast-fed, the infants who ate solid food slept for two more hours per week and woke up two fewer times per night. The findings were published in JAMA Pediatrics, and the study was led by Gideon Lack, a professor at King's College London whose work is funded by the Immune Tolerance Network – which is housed at BRI.
   Section::::Diagnosis.
  
  Section::::Diagnosis.:Criteria.
  
  The diagnostic criteria utilized by the International Classification of Sleep Disorders-Third Edition (ICSD-3) include some dysfunctional eating when the person wake up during the main sleep period, eating unusual or toxic food, negative health consequences. The patient could be injured during these episodes and he might not be conscious and won’t remember them. This criterion differentiates SRED from Night eating syndrome(NES). Patients with NES are conscious during the episode.
  
  Section::::Signs and symptoms.
   Section::::Sleep deprivation and Type 2 diabetes.
  
  Insulin-Resistant Metabolism
  
  Baseline levels of insulin do not signal muscle and fat cells to absorb glucose. When glucose levels are elevated, the pancreas responds by releasing insulin. Blood sugar will then rapidly drop. This can progress to type 2 diabetes.
   Section::::Premeal hunger.
  
  Prior to consuming a meal, the body's energy reserves are in reasonable homeostatic balance. However, when a meal is consumed, there is a homeostasis-disturbing influx of fuels into the bloodstream. When the usual mealtime approaches, the body takes steps to soften the impact of the homeostasis-disturbing influx of fuels by releasing insulin into the blood, and lowering the blood glucose levels. It is this lowering of blood glucose levels that causes premeal hunger, and not necessarily an energy deficit.
  
  Section::::Similar conditions.
   Matthew P Walker, a psychology and neuroscience professor at UC Berkley, published a study during which the participants were deprived of sleep for one night. The New York Times summarized his study as such, "On days when the subjects had not had proper sleep, fattening foods like potato chips and sweets stimulated stronger responses in a part of the brain that helps govern the motivation to eat. But at the same time, the subjects experienced a sharp reduction in activity in the frontal cortex, a higher level part of the brain where consequences are weighted and rational decisions are made.” A brain that has been deprived of sleep for one night is more likely to respond more intensely to junk food but also has the decreased ability to curb that desire. These results were consistent even as the subjects were given extra calories to compensate for the amount of energy expended during those extra hours that the subjects stayed awake, which indicates that one's craving for junk food is not a response to offset an energy deficit. Walker further speculates that one of the biological basis for this reaction could the buildup of adenosine, a metabolic byproduct that may degrade communication between networks in the brain. Adenosine is cleared from the brain during sleep.
   Sleep is important in regulating metabolism. Mammalian sleep can be sub-divided into two distinct phases - REM (rapid eye movement) and non-REM (NREM) sleep. In humans, NREM sleep has four stages, where the third and fourth stages are considered slow-wave sleep (SWS). SWS is considered deep sleep, when metabolism is least active.
  
  In normal metabolic function, the pancreas releases insulin after blood glucose levels raise. Insulin signals muscle and fat cells to absorb glucose from food. As a result, blood glucose levels return to normal.
   While reviewing log data of blood glucose after the fact, signs of Somogyi rebound should be suspected when blood glucose numbers seem "higher" after the insulin dosage has been raised, particularly in the morning. One simple way to determine if nocturnal hypoglycemia may be causing morning hyperglycemia is to have the patient have a high protein snack with a small amount of carbohydrates at bedtime. This will help keep the blood sugar up overnight and prevent the Somogyi effect. If the morning blood sugar decreases, this is indicative of the Somogyi effect and the daily insulin should be decreased.
  
  Section::::Avoidance.
   On the other hand, it is during sleep that beta-amyloid residues are degraded to prevent plaque formation. It is the glymphatic system that is responsible for this and this phenomenon is called glymphatic clearance. Thus, during wakefulness, the AB burden is greater because the metabolic activity and oxidative stress are higher and there is no degradation of the protein by the glymphatic clearance whereas during sleep, the burden will be smaller as there will be less metabolic activity and oxidative stress in addition to the glymphatic clearance that occurs at this time.
   Dysregulation of appetite lies at the root of anorexia nervosa, bulimia nervosa, and binge eating disorder. Anorexia nervosa is a mental disorder characterized as severe dietary restriction and intense fear of weight gain. Furthermore, persons with anorexia nervosa may exercise ritualistically. Individuals who have anorexia have high levels of ghrelin, a hormone that stimulates appetite, so the body is trying to cause hunger, but the urge to eat is being suppressed by the person. Binge eating disorder (commonly referred to as BED) is described as eating excessively (or uncontrollably) between periodic time intervals. The risk for BED can be present in children and most commonly manifests during adulthood. Studies suggest that the heritability of BED in adults is approximately 50%. Similarly to bulimia some people may be involved in purging and binging. They might vomit after food intake or take purgatives. However, the person may still believe they are overweight.
   Lack of sufficient sleep has been suggested as a cause for weight gain or the difficulty in maintaining a healthy weight. Two hormones responsible for regulating hunger and metabolism are leptin, which inhibits appetite and increases energy expenditure, and ghrelin, which increases appetite and reduces energy expenditure. Studies have shown that chronic sleep deprivation is associated with reduced levels of leptin and elevated levels of ghrelin, which together result in increased appetite, especially for high fat and high carbohydrate foods. As a result, sleep deprivation over time may contribute to increased caloric intake and decreased self-control over food cravings, leading to weight gain.
   Section::::Non-rapid eye movement (NREM)-related parasomnias.:Sleep-related eating disorder (SRED).
  
  The Diagnostic and Statistical Manual of Mental Disorders (DSM-V) classifies sleep-related eating disorder under sleepwalking, while ICSD classifies it as NREM-related parasomnia. It is conceptualized as a mixture of binge-eating behavior and arousal disorder. Thereby, preferentially high-caloric food is consumed in an uncontrolled manner. However, SRED should not be confused with nocturnal eating syndrome, which is characterized by an excessive consumption of food before or during sleep in full consciousness. Since sleep-related eating disorders are associated with other sleep disorders, successful treatment of the latter can reduce symptoms of this parasomnia.
   Feelings of hunger as well as plasma ghrelin levels are already elevated after one night of SD, whereas morning serum leptin concentrations remain unaffected. Thus, the results provide further evidence for a disturbing influence of sleep loss on endocrine regulation of energy homeostasis, which in the long run may result in weight gain and obesity.
  
  Section::::Uses.
  
  Section::::Uses.:Scientific study of laboratory animals.
  
  In science, sleep deprivation (of rodents, e.g.) is used in order to study the function(s) of sleep and the biological mechanisms underlying the effects of sleep deprivation.
  
  Some sleep deprivation techniques are:
   On a standard symptom-rating scale, subjects rated markedly stronger feelings of hunger after total SD than after seven hours of sleep (3.9 ± 0.7 versus 1.7 ± 0.3; P = 0.020) or 4.5 hours sleep (2.2 ± 0.5; P = 0.041). Plasma ghrelin levels were 22 ± 10% higher after total SD than after seven hours of sleep (0.85 ± 0.06 versus 0.72 ± 0.04 ng mL(−1); P = 0.048) with intermediate levels of the hormone after 4.5 hours sleep (0.77 ± 0.04 ng mL(−1)).
   Sleep and weight
  
  Section::::Sleep Deprivation and Type 2 Diabetes.
  
  Baseline levels of insulin do not signal muscle and fat cells to absorb glucose. When glucose levels are elevated, the pancreas responds by releasing insulin. Blood sugar will then rapidly drop. This can progress to type 2 diabetes.
   BULLET::::- "About the Man Who Began Flying After Meeting Her," originally published in "The Guardian"
  
  BULLET::::- "Up the Mountain Coming Down Slowly," originally published in "McSweeney's #10"
  
  BULLET::::- "There Are Some Things He Should Keep to Himself"
  
  BULLET::::- "When They Learned to Yelp"
  
  BULLET::::- "After I Was Thrown in the River and Before I Drowned," originally published in "Speaking with the Angel"
  
  Section::::Publication details.
  
  "There Are Some Things He Should Keep to Himself," which consists solely of five blank pages, is not included in the paperback edition.
   NSRED is closely related to night eating syndrome (NES) except for the fact that those suffering from NES are completely awake and aware of their eating and bingeing at night while those suffering from NSRED are sleeping and unaware of what they are doing. NES is primarily considered an eating disorder while NSRED is primarily considered a parasomnia; however, both are a combination of parasomnia and eating disorders since those suffering from NES usually have insomnia or difficulty sleeping and those suffering from NSRED experience symptoms similar to binge eating. Some even argue over whether NES and NSRED are the same or distinct disorders. Even though there have been debates over these two disorders, specialists have examined them to try to determine the differences. Dr. J. Winkelman noted several features of the two disorders that were similar, but he gave one important factor that make these disorders different. In his article "Sleep-Related Eating Disorder and Night Eating Syndrome: Sleep Disorders, Eating Disorders, Or both", Winkelman said, "Both [disorders] involve nearly nightly binging at multiple nocturnal awakenings, defined as excess calorie intake or loss of control over consumption." He also reported that both disorders have a common occurrence of approximately one to five percent of adults, have been predominantly found in women, with a young adult onset, have a chronic course, have a primary morbidity of weight gain, sleep disruption, and shame over loss of control over food intake, have familial bases, and have been observed to have comorbid depression and daytime eating disorders. However, Winkelman said, "The most prominent cited distinction between NES and SRED is the level of consciousness during nighttime eating episodes." Therefore, these two disorders are extremely similar with only one distinction between them. Doctors and psychologists have difficulty differentiating between NES and NSRED, but the distinction of a person's level of consciousness is what doctors chiefly rely on to make a diagnosis. One mistake that is often made is the misdiagnosis of NSRED for NES. However, even though NSRED is not a commonly known and diagnosed disease, many people suffer from it in differing ways while doctors work to find a treatment that works for everyone; several studies have been done on NSRED, such as the one conducted by Schenck and Mahowald. These studies, in turn, provide the basic information on this disorder including the symptoms, behaviors, and possible treatments that doctors are using today.
   BULLET::::- "On Wanting to Have Three Walls up Before She Gets Home," originally published in "The Guardian"
  
  BULLET::::- "Climbing to the Window, Pretending to Dance," originally published in "The New Yorker" in a slightly different form as "Measuring the Jump"
  
  BULLET::::- "She Waits, Seething, Blooming," originally published in "The Guardian"
  
  BULLET::::- "Quiet"
  
  BULLET::::- "Your Mother and I," originally published in "h2s04"
  
  BULLET::::- "Naveed," originally published in "The Guardian"
  
  BULLET::::- "Notes for a Story of a Man Who Will Not Die Alone," originally published in another form in "Ninth Letter"
   Sleep plays a vital role in regulating metabolism and appetite. When sleep deprived, the metabolic system will be out of balance, which will ultimately affect the dietary choices people make. Teens who are sleep deprived crave more carbohydrates. Sleep deprivation is a risk factor for obesity among young adults.
   Nocturnal sleep-related eating disorder
  
  Nocturnal sleep-related eating disorder (NSRED) is a combination of a parasomnia and an eating disorder. It is a NREM parasomnia. It is described as being in a specific category within somnambulism or a state of sleepwalking that includes behaviors connected to a person's conscious wishes or wants. Thus many times NSRED is a person's fulfilling of their conscious wants that they suppress; however, this disorder is difficult to distinguish from other similar types of disorders.
   BULLET::::- Apple AirPort Express with firmware version 7.4.1 or 7.4.2
  
  BULLET::::- Apple AirPort Extreme with firmware version 7.4.1 or 7.4.2
  
  BULLET::::- Apple AirPort Time Capsule
  
  BULLET::::- Apple TV (all generations)
  
  BULLET::::- Computers running Mac OS X Snow Leopard act as a Bonjour sleep proxy server when Internet sharing is enabled.
  
  Section::::External links.
  
  BULLET::::- , see "Mosaics" tab for figures
  
  BULLET::::- , see "Mosaics" tab for figures
  
  BULLET::::- , see "Mosaics" tab for figures
  
  BULLET::::- Fscklog.com: Snow Leopard und 2009er Macs: Wake on WLAN (German, Deutsch)
  
  BULLET::::- Macrumors.com: A Closer Look at Snow Leopard's Wake on Demand Feature
  