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Current Opinion in Clinical Nutrition... Jul 2021The popularity of ketogenic diets in the treatment of obesity has increased dramatically over the last years, namely due to their potential appetite suppressant effect.... (Review)
Review
PURPOSE OF REVIEW
The popularity of ketogenic diets in the treatment of obesity has increased dramatically over the last years, namely due to their potential appetite suppressant effect. The purpose of this review was to examine the latest evidence regarding the impact of ketogenic diets on appetite.
RECENT FINDINGS
The majority of the studies published over the last 2 years adds to previous evidence and shows that ketogenic diets suppress the increase in the secretion of the hunger hormone ghrelin and in feelings of hunger, otherwise see when weight loss is induced by non-ketogenic diets. Research done using exogenous ketones point out in the same direction. Even though the exact mechanisms by which ketogenic diets suppress appetite remain to be fully determined, studies show that the more ketotic participants are (measured as β-hydroxybutyrate plasma concentration), the smaller is the increase in ghrelin and hunger and the larger is the increase in the release of satiety peptides. Further evidence for a direct effect of ketones on appetite comes from studies using exogenous ketones.
SUMMARY
The appetite suppressant effect of ketogenic diets may be an important asset for improving adherence to energy restricted diets and weight loss outcomes.
Topics: Appetite; Appetite Regulation; Diet, Ketogenic; Ghrelin; Humans; Hunger; Weight Loss
PubMed: 33883420
DOI: 10.1097/MCO.0000000000000760 -
Protein and Peptide Letters 2022Gut peptides are small peptides secreted by gut endocrine cells that can modulate the roles and functions of different organs through signaling. Gut peptides can also... (Review)
Review
Gut peptides are small peptides secreted by gut endocrine cells that can modulate the roles and functions of different organs through signaling. Gut peptides can also majorly impact the body's energy homeostasis by regulating appetite and energy metabolism. The gut-brain axis (GBA) is bidirectional communication between the central nervous system (CNS) and the peripheral enteric nervous system. The regulation of appetite acts by hypothalamic neuronal activity. The complex interaction of hedonic and homeostatic factors implicates appetite regulation. In the CNS, the hypothalamus and brainstem have a dominating role in appetite regulation. The arcuate nucleus (ARC) of the hypothalamus plays a vital role in energy homeostasis, while other nuclei also play a role in appetite regulation. The gut conveys peripheral information about energy balance to the brain via gut peptides and receptors for the digestion of food. The varied gut peptides have different actions on appetite regulation.
Topics: Appetite Regulation; Brain; Energy Metabolism; Hypothalamus; Peptides
PubMed: 36125839
DOI: 10.2174/0929866529666220920150127 -
Nutrients Jan 2023The objectives of this paper are to first present physiological and ecological aspects of the unique motivational state of sodium appetite, then to focus on systemic... (Review)
Review
The objectives of this paper are to first present physiological and ecological aspects of the unique motivational state of sodium appetite, then to focus on systemic physiology and brain mechanisms. I describe how laboratory protocols have been developed to allow the study of sodium appetite under controlled conditions, and focus on two such conditions specifically. The first of these is the presentation a sodium-deficient diet (SDD) for at least one week, and the second is accelerated sodium loss using SDD for 1-2 days coupled with the diuretic furosemide. The modality of consumption is also considered, ranging from a free intake of high concentration of sodium solution, to sodium-rich food or gels, and to operant protocols. I describe the pivotal role of angiotensin and aldosterone in these appetites and discuss whether the intakes or appetite are matched to the physiological need state. Several brain systems have been identified, most recently and microscopically using molecular biological methods. These include clusters in both the hindbrain and the forebrain. Satiation of sodium appetite is often studied using concentrated sodium solutions, but these can be consumed in apparent excess, and I suggest that future studies of satiation might emulate natural conditions in which excess consumption does not occur, using either SDD only as a stimulus, offering a sodium-rich food for the assessment of appetite, or a simple operant task.
Topics: Appetite; Sodium; Diuretics; Furosemide; Satiation; Sodium, Dietary
PubMed: 36771327
DOI: 10.3390/nu15030620 -
Nutrients Aug 2023With the increasing prevalence of energy metabolism disorders such as diabetes, cardiovascular disease, obesity, and anorexia, the regulation of feeding has become the... (Review)
Review
With the increasing prevalence of energy metabolism disorders such as diabetes, cardiovascular disease, obesity, and anorexia, the regulation of feeding has become the focus of global attention. The gastrointestinal tract is not only the site of food digestion and absorption but also contains a variety of appetite-regulating signals such as gut-brain peptides, short-chain fatty acids (SCFAs), bile acids (BAs), bacterial proteins, and cellular components produced by gut microbes. While the central nervous system (CNS), as the core of appetite regulation, can receive and integrate these appetite signals and send instructions to downstream effector organs to promote or inhibit the body's feeding behaviour. This review will focus on the gut-brain axis mechanism of feeding behaviour, discussing how the peripheral appetite signal is sensed by the CNS via the gut-brain axis and the role of the central "first order neural nuclei" in the process of appetite regulation. Here, elucidation of the gut-brain axis mechanism of feeding regulation may provide new strategies for future production practises and the treatment of diseases such as anorexia and obesity.
Topics: Humans; Anorexia; Brain-Gut Axis; Appetite; Obesity; Eating
PubMed: 37686760
DOI: 10.3390/nu15173728 -
Appetite Jan 2022
Topics: Appetite; Humans; Surveys and Questionnaires
PubMed: 34610394
DOI: 10.1016/j.appet.2021.105731 -
The British Journal of Nutrition Jun 2020Expensive and extensive studies on the epidemiology of excessive Na intake and its pathology have been conducted over four decades. The resultant consensus that dietary... (Review)
Review
Expensive and extensive studies on the epidemiology of excessive Na intake and its pathology have been conducted over four decades. The resultant consensus that dietary Na is toxic, as well as the contention that it is less so, ignores the root cause of the attractiveness of salted food. The extant hypotheses are that most Na is infiltrated into our bodies via heavily salted industrialised food without our knowledge and that mere exposure early in life determines lifelong intake. However, these hypotheses are poorly evidenced and are meagre explanations for the comparable salt intake of people worldwide despite their markedly different diets. The love of salt begins at birth for some, vacillates in infancy, climaxes during adolescent growth, settles into separate patterns for men and women in adulthood and, with age, fades for some and persists for others. Salt adds flavour to food. It sustains and protects humans in exertion, may modulate their mood and contributes to their ailments. It may have as yet unknown benefits that may promote its delectability, and it generates controversy. An understanding of the predilection for salt should allow a more evidence-based and effective reduction of the health risks associated with Na surfeit and deficiency. The purpose of this brief review is to show the need for research into the determinants of salt intake by summarising the little we know.
Topics: Adult; Aged; Aged, 80 and over; Appetite; Diet; Eating; Female; Flavoring Agents; Humans; Male; Middle Aged; Nutritional Requirements; Sodium, Dietary
PubMed: 31959267
DOI: 10.1017/S0007114520000173 -
Current Opinion in Psychiatry Nov 2019The aim of this review is to describe animal models that simulate the features of eating disorders. The literature pertaining to animal models that are of relevance for... (Review)
Review
PURPOSE OF REVIEW
The aim of this review is to describe animal models that simulate the features of eating disorders. The literature pertaining to animal models that are of relevance for clinical eating disorders and the possible underpinning mechanisms was reviewed using PubMed, Ovid database and Google Scholar.
RECENT FINDINGS
New refinements of the circuits regulated by neurotransmitters and neuropeptides which instigate eating behaviours and the various feedback pathways which monitor acute and chronic nutrient status continue to be discovered. Moreover, work with the animal models that simulate the behavioural features and risk factors related to eating disorders is flourishing and providing new insights into possible causal mechanisms. For example, rodents develop binge-eating behaviours if they are intermittently exposed to processed, palatable foods and/or sugar adulterated drinks. This led to the controversial conceptualization of binge eating as a form of food addiction. Self-starvation taken to a fatal consequence such as occurs in anorexia nervosa can emerge in rodents exposed to triggers like social exclusion and/or the opportunity to exercise.
SUMMARY
There are plausible animal models for both anorexia nervosa and binge-eating disorders. These can be used to elaborate the theoretical models to explain the mechanisms underpinning eating disorders.
Topics: Animals; Appetite; Disease Models, Animal; Feeding Behavior; Feeding and Eating Disorders
PubMed: 31335333
DOI: 10.1097/YCO.0000000000000550 -
Gastroenterology Clinics of North... Jun 2023At usual weight, energy intake and expenditure are coupled and covary to maintain body weight (energy stores). A change in energy balance, especially weight loss,... (Review)
Review
At usual weight, energy intake and expenditure are coupled and covary to maintain body weight (energy stores). A change in energy balance, especially weight loss, invokes discoordinated effects on energy intake and output that favor return to previous weight. These regulatory systems reflect physiological changes in systems regulating energy intake and expenditure rather than a lack of resolve. The biological and behavioral physiology of dynamic weight change are distinct from those of attempts at static weight maintenance of an altered body weight. This suggests that optimal therapeutic approaches to losing or gaining vs. sustaining weight changes are different for most individuals.
Topics: Humans; Appetite; Obesity; Weight Loss; Energy Intake; Energy Metabolism
PubMed: 37197875
DOI: 10.1016/j.gtc.2023.03.004 -
International Journal of Molecular... Apr 2023Appetite dysregulation is one of the factors contributing to anorexia, bulimia nervosa, obesity, and diabetes. Essential oils or fragrant compounds have been proven to... (Review)
Review
Appetite dysregulation is one of the factors contributing to anorexia, bulimia nervosa, obesity, and diabetes. Essential oils or fragrant compounds have been proven to regulate food intake and energy expenditure; hence, this study aimed to summarize their effects on appetite and the underlying mechanisms. The PubMed and Web of Science databases were searched until July 2022. Only two of the 41 studies were performed clinically, and the remaining 39 used animal models. Oral administration was the most common route, and a dosage range of 100-2000 mg/kg for mice or 2-32 mg/kg for rats was applied, with a duration of 12 days to 4 weeks, followed by inhalation (10-10 mg/cage or 10-10 mg/cm within 1 h). Approximately 11 essential oil samples and 22 fragrant compounds were found to increase appetite, while 12 essential oils and seven compounds decreased appetite. These fragrant components can exert appetite-regulating effects via leptin resistance, the activity of sympathetic/parasympathetic nerves, or the mRNA expression of neuropeptide Y (NPY)/agouti-related protein (AgRP), cocaine- and amphetamine-regulated transcript (CART)/proopiomelanocortin (POMC) in the hypothalamus. Fragrance memory and cognitive processes may also play roles in appetite regulation. The findings of this study accentuate the potential of essential oils and fragrant compounds to regulate appetite and eating disorders.
Topics: Rats; Mice; Animals; Appetite; Oils, Volatile; Nerve Tissue Proteins; Neuropeptide Y; Hypothalamus; Leptin; Appetite Regulation; Agouti-Related Protein; Eating
PubMed: 37175666
DOI: 10.3390/ijms24097962 -
Current Opinion in Neurobiology Oct 2020All meals come to an end. This is because eating and drinking generate feedback signals that communicate to the brain what and how much has been consumed. Here we review... (Review)
Review
All meals come to an end. This is because eating and drinking generate feedback signals that communicate to the brain what and how much has been consumed. Here we review our current understanding of how these feedback signals regulate appetite. We first describe classic studies that surgically manipulated the gastrointestinal tract and measured the effects on behavior. We then highlight recent experiments that have used in vivo neural recordings to directly observe how ingestion modulates circuit dynamics in the brain. A general theme emerging from this work is that eating and drinking generate layers of feedback signals, arising sequentially from different tissues in the body, that converge on individual neurons in the forebrain to regulate hunger and thirst.
Topics: Appetite; Brain; Eating; Hunger; Neurons; Thirst
PubMed: 32311645
DOI: 10.1016/j.conb.2020.03.007