Breakfast skipping in prepubertal obese children: hormonal, metabolic and cognitive consequences

Physical inactivity and breakfast skipping caused visceral fat accumulation in rats

Physical inactivity as well as breakfast skipping is known as risk factor for various metabolic diseases, such as obesity and type 2 diabetes. We have previously reported that a breakfast skipping model, in which the timing of feeding is delayed, induces abnormal lipid metabolism by altering the circadian rhythm of lipid metabolism-related genes in rats. The purpose of this study was to elucidate the synergistic effect of physical inactivity and breakfast skipping on lipid metabolism. We adopted sciatic neurectomized rats as physically inactive models, because we confirmed that the rats mildly decreased their spontaneous locomotor activity compared to sham-operated rats. And then the physically inactive model rats were fed a mild high-fat diet during zeitgeber time (ZT) 12-0 in the control group and ZT16-0 in the breakfast skipping group for 11 days. Body weight gain and total food intake were similar in both groups. Breakfast skipping induced a significant visceral fat accumulation, which was not observed in our previous breakfast skipping or physically inactive studies. The mRNA levels of clock and lipogenesis-related genes were altered by breakfast skipping in the liver and epididymal adipose tissue, and serum insulin level was altered by breakfast skipping. These results suggest that physical inactivity and breakfast skipping synergistically induces drastic visceral fat accumulation due to the alteration of circadian clock and lipid metabolism in the liver and adipose tissue. Therefore, regular feeding timing plays an important role in the health of a sedentary modern society.

Delayed feeding of a high-sucrose diet led to increased body weight by affecting the circadian rhythm of body temperature and hepatic lipid-metabolism genes in rats

Skipping breakfast is an irregular feeding behavior, typically in young people. In our previous study, we established a 4 h-delayed feeding protocol for rats as a breakfast-skipping model and showed that the 4 h-delayed feeding of a high-fat diet led to body weight gain in rats. Excess sucrose induces metabolic syndrome and fatty liver. Recently, excess sucrose intake has received increased attention. Young people generally consume more sugar than adults do. In the present study, we investigated whether a 4 h-delayed feeding promoted high-sucrose diet-induced abnormalities in lipid metabolism, such as fatty liver and obesity in rats. The 4 h-delayed feeding rats showed increased body weight gain, although it did not induce fatty liver and hyperlipidemia compared to normal feeding rats. Serum insulin concentration during the feeding period was higher than in the control rats, suggesting that slight insulin resistance was induced by the 4 h-delayed feeding. The surge in body temperature was also delayed by 4 h in response to the 4 h-delayed feeding. This delay would result in less energy expenditure to increase body weight. The oscillations of hepatic lipid and glucose metabolism-related gene expression were delayed by almost 2-4 h, and the clock genes were delayed by approximately 2 h. The 4 h-delayed feeding induced weight gain by affecting body temperature, insulin resistance, and circadian oscillation of lipid metabolism-related genes in rats fed a high-sucrose diet, suggesting that a high sucrose intake with breakfast skipping leads to obesity.

Delayed Meal Timing, a Breakfast Skipping Model, Increased Hepatic Lipid Accumulation and Adipose Tissue Weight by Disintegrating Circadian Oscillation in Rats Fed a High-Cholesterol Diet

Background: To investigate whether shifted timing of eating, breakfast skipping, induces alterations in the circadian clock and abnormal lipid metabolism, we have established a delayed meal timing (DMT) protocol for rats, which started eating food 4 h delay. In the present study, control and DMT rats were fed a high-cholesterol diet during zeitgeber time (ZT) 12-24 and ZT 16-4, respectively. The DMT protocol increased the hepatic lipids and epididymal adipose tissue weight without changes in food intake and body weight. The surge in body temperature was delayed by 4 h in the DMT group, suggesting that energy expenditure was decreased in response to DMT. The peaks of the diurnal rhythm of serum non-esterified fatty acids and insulin were delayed by 2 and 4 h due to DMT, respectively. The oscillation peaks of hepatic de novo fatty acid synthesis gene expression was delayed by 4 h in response to DMT, whereas the peak of hepatic clock genes were 2 h delayed or not by DMT. Although metabolic oscillation is considered to be controlled by clock genes, the disintegration rhythms between the clock genes and lipid metabolism-related genes were not observed in rats fed a high-fat diet in our previous study. These data suggest that the circadian rhythm of de novo fatty acid metabolism is regulated by timing of eating, but is not directly controlled by clock genes. The present study suggests that breakfast skipping would complicate fatty liver and body fat accumulation.

Breakfast: A Crucial Meal for Adolescents' Cognitive Performance According to Their Nutritional Status. The Cogni-Action Project

This study aimed to determine whether pupils who have breakfast just before a cognitive demand, do not regularly skip breakfast, and consume a high-quality breakfast present higher cognitive performance than those who do not; furthermore, to establish differences according to their nutritional status. In this study, 1181 Chilean adolescents aged 10–14 years participated. A global cognitive score was computed through eight tasks, and the body mass index z-score (BMIz) was calculated using a growth reference for school-aged adolescents. The characteristics of breakfast were self-reported. Analyses of covariance were performed to determine differences in cognitive performance according to BMIz groups adjusted to sex, peak height velocity, physical fitness global score, and their schools. A positive association was found in adolescents’ cognitive performance when they had breakfast just before cognitive tasks, did not regularly skip breakfast, presented at least two breakfast quality components, and included dairy products. No significant differences were found between breakfast components, including cereal/bread and fruits/fruit juice. Finally, pupils who were overweight/obese who declared that they skipped breakfast regularly presented a lower cognitive performance than their normal-BMIz peers. These findings suggest that adolescents who have breakfast just prior to a cognitive demand and regularly have a high quality breakfast have better cognitive performance than those who do not. Educative nutritional strategies should be prioritized, especially in “breakfast skippers” adolescents living with overweight/obesity.

Effects of eating breakfast on children and adolescents: A systematic review of potentially relevant outcomes in economic evaluations

BACKGROUND

Breakfast is often described as the most important meal of the day. Several studies have focused on examining if breakfast habits have any short-term effects on school attendance, academic achievement, and general health in children and adolescents. Informed decisions of whether to promote eating breakfast or not require a more long-term perspective.

OBJECTIVE

The aim of this study was to conduct a systematic review of scientific publications studying the effects identified as potentially relevant for the economic evaluation of eating breakfast in children and adolescents.

DESIGN

A systematic literature review was conducted. Studies were identified by searching the electronic databases PubMed, CINAHL, Web of Science, and PsycINFO between January 2000 and October 2017. The inclusion criteria applied were published articles from peer-reviewed journals with full text in English, quantitative studies collecting primary data with school-aged children, and adolescents aged from 6 to 18 years as participants, performed entirely or partly in countries with advanced economies, except Japan and Taiwan.

RESULTS

Twenty-six studies fulfilled the inclusion criteria, and studies that were judged to be of at least moderate quality were included in the analysis. The results of the review of eating breakfast studies showed positive and conclusive effects on cognitive performance, academic achievement, quality of life, well-being and on morbidity risk factors.

CONCLUSIONS

The overall assessment of the studies indicated positive effects of eating breakfast. How the identified effects influence societal costs and an individual's quality-adjusted life years require further research.

Skipping Breakfast and a Meal at School: Its Correlates in Adiposity Context. Report from the ABC of Healthy Eating Study of Polish Teenagers

Little is known on skipping breakfast and a meal at school, especially considered together. The study identified nutrition knowledge-related, lifestyle (including diet quality, physical activity, and screen time) and socioeconomic correlates of skipping breakfast and a meal at school, considered together or alone and assessed the association of skipping these meals with adiposity markers in Polish teenagers. The sample consisted of 1566 fourth and fifth grade elementary school students (11–13 years). The study was designed as a cross-sectional study. Data related to the consumption of selected food items and meals, physical activity, screen time, sociodemographic factors, and nutrition knowledge (all self-reported) were collected (in 2015–2016) with a short form of a food frequency questionnaire. Respondents reported the usual consumption of breakfast (number of days/week) and a meal or any food eaten at school (number of school days/week) labelled as ‘a meal at school’. The measurements of body weight, height, and waist circumference were taken. BMI-for-age ≥25 kg/m² was considered as a marker of overweight/obesity (general adiposity), while waist-to-height ratio ≥0.5 as a marker of central obesity (central adiposity). A multivariate logistic regression was applied to verify the association between variables. A total of 17.4% of teenagers frequently skipped breakfast (4–7 days/week), 12.9% frequently skipped a meal at school (3–5 school days/week), while 43.6% skipped both of these meals a few times a week. Predictors of skipping breakfast and/or a meal at school were female gender, age over 12 years, urban residence, lower family affluence, lower nutrition knowledge, higher screen time, and lower physical activity. In comparison to “never-skippers,” “frequent breakfast skippers” were more likely to be overweight/obese (odds ratio, OR 1.89; 95% confidence interval, 95%CI 1.38, 2.58) and centrally obese (OR 1.63; 95%CI 1.09, 2.44), while skippers a few times a week of both of these meals were more likely to be overweight/obese (OR 1.37; 95%CI 1.06, 1.78). Concluding, we estimated that a large percentage of Polish teenagers (approx. 44%) usually skipped both breakfast and a meal at school a few times a week. Similar predictors of skipping breakfast and predictors of skipping a meal at school were identified. Special attention should be paid to promoting shortening screen time and increasing physical activity and teenagers’ nutrition knowledge which are relatively easily modifiable correlates. The study shows that skipping both of these meals a few times a week was associated with general adiposity and also strengthens previous evidence showing the association of frequent skipping breakfast with general and central adiposity.

UJI PSIKOMOTOR WAKTU REAKSI PADA SISWA YANG SARAPAN DAN TIDAK SARAPAN

Background: Eating habits that are currently owned by elementary school age children are difficult to eat with amoung should be three times a day according to the needs, one of them is breakfast. When they didn’t breakfast before went to school they will deficiency  of intake. Energy that can cause the children quickly experience fatigue and less to concentration for accepting the lesson in the school. Psycomotor test reaction time is the interval between receiving stimulus with a respon do main which includes movement behaviour and physical coordination, motor skills.Objectives: The purpose of this research is to analyze test time reaction psychomotor and to provides an overview of thetime difference reaction between students who breakfast and did not have breakfastMethods: This study is an observational study using cross sectional design. The sample in this study was school children aged 9-12 years  much as 100 children by measuring the reaction time of students who had breakfast or not breakfast with a special tool called Body ReactionResults: The result showed that of 45 % students have a habit of breakfast and at 55 % students do not have a habit of breakfast with psychomotor test time reaction between students who breakfast is better than the students who did not breakfast( p-value 0.01<0.05 ).Conclusions: There is the differencein psychomotor test time reaction between students who breakfast and did not have breakfast.Explained that the students also took a chance breakfast first before he left school, because with breakfast will be triggered growth and maximize the capability of at school.ABSTRAKLatar Belakang: Kebiasaan makan yang saat ini dimiliki oleh anak usia sekolah dasar adalah sulitnya untuk makan dengan jumlah yang seharusnya yaitu 3 kali dalam sehari sesuai dengan kebutuhan, salah satunya adalah sarapan. Disaat mereka tidak sarapan sebelum berangkat ke sekolah mereka akan kekurangan asupan energi yang dapat menyebabkan anak tersebut cepat mengalami kelelahan dan kurang konsentrasi dalam menerima pelajaran saat di sekolah. Uji psikomotor waktu reaksi adalah interval antara penerimaan stimulus dengan suatu responyang meliputi perilaku gerakan dan koordinasi jasmani, ketrampilan motorik dan kemampuan fisik seseorang.Tujuan: Untuk menganalisis hasil uji psikomotor waktu reaksi serta untuk memberikan gambaran mengenai perbedaan waktu reaksi antara siswa yang sarapan dan tidak sarapanMetode: Penelitian ini merupakan penelitian yang bersifat observasional dengan menggunakan design cross sectional. Sampel dalam penelitian ini adalah anak sekolah usia 9-12 tahun yaitu sebanyak 100 anak dengan cara mengukur waktu reaksi siswa baik yang sudah sarapan atau tidak sarapan dengan alat khusus yaitu Body ReactionHasil: Hasil penelitian menunjukkan bahwa sebesar 45% siswa memiliki kebiasaan sarapan dan sebesar 55% siswa tidak memiliki kebiasaan sarapan dengan hasil uji psikomotor waktu reaksi antara siswa yang sarapan lebih baik dibandingkan dengan siswa yang tidak sarapan (p-value 0,01<0,05).Kesimpulan: Terdapat perbedaan uji psikomotor waktu reaksi antara siswa yang sarapan dan tidak sarapan. Sebaiknya siswa menyempatkan sarapan terlebih dahulu sebelum berangkat sekolah, karena dengan sarapan akan memacu pertumbuhan dan memaksimalkan kemampuan di sekolah.

Environmental Forces that Shape Early Development: What We Know and Still Need to Know

Understanding health requires more than knowledge of the genome. Environmental factors regulate gene function through epigenetics. Collectively, environmental exposures have been called the "exposome." Caregivers are instrumental in shaping exposures in a child's initial years. Maternal dietary patterns, physical activity, degree of weight gain, and body composition while pregnant will influence not only fetal growth, but also the infant's metabolic response to nutrients and energy. Maternal over- or underweight, excess caloric intake, nutrient imbalances, glucose dysregulation, and presence of chronic inflammatory states have been shown to establish risk for many later chronic diseases. During the period from birth to age 3 y, when the infant's metabolic rate is high and synaptogenesis and myelination of the brain are occurring extremely rapidly, the infant is especially prone to damaging effects from nutrient imbalances. During this period, the infant changes from a purely milk-based diet to one including a wide variety of foods. The process, timing, quality, and ultimate dietary pattern acquired are a direct outcome of the caregiver-infant feeding relationship, with potentially lifelong consequences. More research on how meal time interactions shape food acceptance is needed to avoid eating patterns that augment existing disease risk. Traditional clinical trials in nutrition, meant to isolate single factors for study, are inadequate to study the highly interconnected realm of environment-gene interactions in early life. Novel technologies are being used to gather broad exposure data on disparate populations, employing pioneering statistical approaches and correlations applied specifically to the individual, based on their genetic make-up and unique environmental experiences.

Memory and potential correlates among children in Jordan

BACKGROUND

Cognitive functioning hugely affects the performance of tasks of different complexity. Memory, one of the most important cognitive skills, allows children to practice and acquire necessary skills and knowledge and interact with the surrounding environment. Therefore, it is crucial to study the factors that influence the memory of children. The main purpose of his study was to investigate different variables related to memory in school aged children (5-9 years, N = 434).

METHODS

Parents of the participants provided information about child's daily behavior, child's school academic achievement, work and family income data and demographics. Memory skills in children were assessed by using the Leiter International Performance Scale -Revised.

RESULTS

The score of memory increased 2.53 points with upsurge in maternal occupation level, 3.08 points when the child ate breakfast and 4.51 points when the child daily slept nine hours and more. By contrast, increased family income and smoking by father resulted in decreased scores in memory.

CONCLUSION

Screening for and understanding of memory and relevant factors are vital for broad understanding of children's capabilities and weaknesses as well as for developing appropriate interventions.

Obese children aged 4-6 displayed decreased fasting and postprandial ghrelin levels in response to a test meal

AIM

Ghrelin is a hunger hormone that plays a role in glucose homoeostasis and its levels increase before a meal and decrease during and after eating. This study compared the fasting ghrelin and insulin levels of obese children aged 4-6 with those of normal weight children and tested postprandial ghrelin levels in the obese children after a standard breakfast.

METHODS

We recruited 67 children at Lund University Hospital from 2008 to 2011. They comprised 30 obese children from a weight study and 37 normal weight children receiving minor elective surgery. Their mean ages were 4.7 ± 0.6 and 4.3 ± 0.8 years, respectively. The obese children ate a standard breakfast, and postprandial ghrelin was measured after 60 minutes.

RESULTS

The obese children had lower ghrelin levels than the controls (p < 0.01). A significant inverse relation was found between body mass index and fasting ghrelin levels. Obese children had significantly lower fasting ghrelin levels after a standard breakfast (p < 0.01), but there were no gender-related differences.

CONCLUSION

Obese children aged 4-6 years had reduced ghrelin and increased insulin levels in the fasting state and postprandial ghrelin was suppressed, suggesting that their energy metabolism was already dysregulated at this young age. Early obesity interventions are essential.

Methodological Challenges in Studies Examining the Effects of Breakfast on Cognitive Performance and Appetite in Children and Adolescents

Breakfast is purported to confer a number of benefits on diet quality, health, appetite regulation, and cognitive performance. However, new evidence has challenged the long-held belief that breakfast is the most important meal of the day. This review aims to provide a comprehensive discussion of the key methodological challenges and considerations in studies assessing the effect of breakfast on cognitive performance and appetite control, along with recommendations for future research. This review focuses on the myriad challenges involved in studying children and adolescents specifically. Key methodological challenges and considerations include study design and location, sampling and sample section, choice of objective cognitive tests, choice of objective and subjective appetite measures, merits of providing a fixed breakfast compared with ad libitum, assessment and definition of habitual breakfast consumption, transparency of treatment condition, difficulty of isolating the direct effects of breakfast consumption, untangling acute and chronic effects, and influence of confounding variables. These methodological challenges have hampered a clear substantiation of the potential positive effects of breakfast on cognition and appetite control and contributed to the debate questioning the notion that breakfast is the most important meal of the day.

The Effects of Breakfast and Breakfast Composition on Cognition in Children and Adolescents: A Systematic Review

Breakfast is thought to be beneficial for cognitive and academic performance in school children. However, breakfast is the most frequently skipped meal, especially among adolescents. The aim of the current article was to systematically review the evidence from intervention studies for the effects of breakfast on cognitive performance in children and adolescents. The effects of breakfast were evaluated by cognitive domain and breakfast manipulation. A total of 45 studies reported in 43 articles were included in the review. Most studies considered the acute effect of a single breakfast (n = 34). The acute studies looked at breakfast compared with no breakfast (n = 24) and/or comparisons of breakfast type (n = 15). The effects of chronic school breakfast program interventions were evaluated in 11 studies. The findings suggest that breakfast consumption relative to fasting has a short-term (same morning) positive domain-specific effect on cognition. Tasks requiring attention, executive function, and memory were facilitated more reliably by breakfast consumption relative to fasting, with effects more apparent in undernourished children. Firm conclusions cannot be made about the acute effects of breakfast composition and the effects of chronic breakfast interventions because there are too few studies and these largely report inconsistent findings. This review also highlights methodologic limitations of the existing research. These include a lack of research on adolescents, few naturalistic breakfast manipulations or testing environments, small samples, and insensitive cognitive tests.

Nutrient Intake, Diet Quality, and Weight Measures in Breakfast Patterns Consumed by Children Compared with Breakfast Skippers: NHANES 2001-2008

Most studies showing that children consuming breakfast have better nutrient intakes, diet quality, and lower weight than breakfast skippers have the incorrect premise that breakfast meals are homogeneous. The purpose of this study was to classify breakfast meals into patterns and determine the association of the breakfast patterns with daily and breakfast nutrient intakes, diet quality, and weight. Data from children (2-18 years of age; N = 14,200) participating in the National Health and Nutrition Examination Survey 2001-2008 were used. Intake was determined from one day 24-hour dietary recalls. Diet quality was measured using the Healthy Eating Index-2005 (HEI-2005). Body mass index (BMI) z-scores were determined. Twelve patterns (including No Breakfast [∼19% of population]), explaining 63% of the variance in energy from breakfast, were examined. Covariate adjusted general linear models were used to compare outcome variables of consumers of different patterns with breakfast skippers. The p value was Bonferroni corrected (< 0.05/12 = < 0.0042). Consumers of the Eggs/Grain/Meat, Poultry, Fish (MPF)/ Fruit Juice (FJ) and MPF/ Grain/FJ patterns showed higher daily intakes of saturated fats, solid fats, and sodium and lower daily intakes of added sugars than breakfast skippers. Consumers of most breakfast patterns showed higher daily intakes of some nutrients of public health concern (dietary fiber, vitamin D, calcium, and potassium); however, those consuming the Grain or MPF/Grain/FJ pattern did not. Consumers of the Grain/Lower Fat Milk (LFM)/Sweets/FJ, Presweetened (PS) Ready-to-eat Cereal (RTEC)/ LFM, RTEC/LFM, Cooked Cereal/Milk/FJ, and Whole Fruit patterns had higher total HEI-2005 scores than breakfast skippers; those consuming the MPF/ Grain/FJ pattern had lower diet quality than breakfast skippers. Consumption of the Grain/ LFM/Sweets/FJ, PSRTEC/whole milk, Soft Drinks/ FJ/Grain/Potatoes, RTEC/whole milk, and Cooked Cereal/ Milk/ FJ patterns was associated with lower BMI z-scores than seen in breakfast skippers. There are dietary and weight advantages of consuming breakfast, especially breakfasts that include grains, cereals, LFM, and fruit/ FJ, in contrast to the potential adverse effects of skipping breakfast.

The Relationship between Habitual Breakfast Consumption Frequency and Academic Performance in British Adolescents

Breakfast has been shown to be beneficial for cognitive and academic performance in school children. However, there is a paucity of studies which examine the relationship between breakfast consumption and academic performance and a complete absence of studies in UK school children. The aim of this study, therefore, was to examine the association between habitual breakfast consumption frequency and Cognitive Abilities Test (CAT) performance, a reasoning test routinely used in UK schools. Adolescents aged 11-13 years (n = 292; males: 53.8%) completed a questionnaire to report usual weekly breakfast intake frequency. Breakfast was subjectively defined by the participants. Habitual weekly breakfast consumption frequency was categorized as rare (0-2 days), occasional (3-4 days), or frequent (5-7 days). Participants' CAT performance was used as a proxy measure of academic performance. The CAT has three components: verbal, non-verbal, and quantitative reasoning. Normative standard age scores (SAS) for verbal, non-verbal, quantitative reasoning, and overall mean SAS were obtained from school records and hierarchical linear regression models were applied, adjusting for the confounders: gender, ethnicity, socio-economic status, English as an Additional Language, and body mass index. Habitual breakfast consumption frequency did not significantly predict any CAT SAS in all models (crude and adjusted). However, methodological considerations which could account for this disagreement with previous research, were identified. These included the isolation of school-day breakfast consumption, use of a standard definition of breakfast, and measurement of actual academic performance. The findings of the current study suggest more comprehensive ways in which future studies might investigate the relationship between habitual breakfast consumption and academic performance.

The effect of breakfast composition and energy contribution on cognitive and academic performance: a systematic review

BACKGROUND

Most studies that assess the effects of breakfast on subsequent mental abilities compared performance in subjects who had or had not consumed this meal. However, characteristics of breakfast itself may induce metabolic and hormonal alterations of the gastrointestinal tract and potentially modify cognitive performance. Moreover, as far as the evidence on the positive effects of having breakfast is becoming more robust, interest may shift to the specific characteristics of an adequate breakfast.

OBJECTIVE

The objective was to summarize existing evidence on the role of nutrient composition or energy intake at breakfast on the accomplishment of school-related tasks and cognition.

DESIGN

We conducted a systematic review of the literature through the PubMed database.

RESULTS

From the literature search, we identified 102 articles, 15 of which met the inclusion criteria. Of these, 3 studies provided information on the relation between cognitive and academic performance and energy intake at breakfast, 11 provided the same information for the macronutrient composition of breakfast, and 1 investigated both the aspects. Eleven studies considered breakfast meals differing in glycemic index/load. Selected studies were generally carried out in well-nourished children and adults of both sexes from general education. They were mostly experimental studies of short duration and had a limited number of subjects. Cognitive and academic performance was investigated by looking at multiple domains, including memory, attention, reasoning, learning, and verbal and math abilities, with a variety of test batteries scheduled at different time points in the morning. Breakfast options differed in terms of included foods and place and time of administration.

CONCLUSIONS

There is insufficient quantity and consistency among studies to draw firm conclusions. However, whereas the hypothesis of a better and more sustained performance with a breakfast providing >20% daily energy intake still needs substantiation, there does appear to be emerging, but still equivocal, evidence that a lower postprandial glycemic response is beneficial to cognitive performance.

Systematic review of ghrelin response to food intake in pediatric age, from neonates to adolescents

OBJECTIVE

Food intake and energy balance are regulated during the lifespan with critical changes in each specific period (infancy, adulthood, aging). Some of ghrelin's changes may contribute to the regulation of food intake and weight in children. We aimed to analyze the ghrelin response to feeding in lean or obese subjects from birth to adolescence.

METHODS

We searched PubMed, Scopus, Google Scholar, Cochrane, and EMBASE (December 1999 to February 2013) and identified 62 relevant articles, of which 29 were suitable to be included.

RESULTS AND CONCLUSIONS

Total ghrelin response to meals is particular, with refractoriness in neonates and lean children and an inhibition that starts from puberty. Total ghrelin levels are decreased after meals, irrespective of pubertal stages in obese children and adolescents. Conversely, total ghrelin is decreased after an oral glucose tolerance test in all ages, with the exception of neonates. Data on unacylated ghrelin response are scant but resemble those of total ghrelin. The acylated ghrelin response to meals or oral glucose tolerance test is discordant, although a precocious inhibition followed by a rise back is present in both lean and obese children. The post-feeding profile in children with Prader-Willi syndrome is also peculiar, with a conserved and deeper inhibition of all ghrelin forms.