No Acute Effects of Exogenous Glucose-Dependent Insulinotropic Polypeptide on Energy Intake, Appetite, or Energy Expenditure When Added to Treatment With a Long-Acting Glucagon-Like Peptide 1 Receptor Agonist in Men With Type 2 Diabetes.

OBJECTIVE: Dual incretin receptor agonists in clinical development have shown reductions in body weight and hemoglobin A1c (HbA1c) in patients with type 2 diabetes, but the impact of glucose-dependent insulinotropic polypeptide (GIP) receptor activation remains unclear. Here, we evaluated the effects of high-dose exogenous GIP on energy intake, energy expenditure, plasma glucose, and glucose-regulating hormones in patients with type 2 diabetes treated with a long-acting glucagon-like peptide 1 receptor (GLP-1R) agonist. RESEARCH DESIGN AND METHODS: In a randomized, double-blind design, men with type 2 diabetes (n = 22, mean ± SEM HbA1c 6.8 ± 0.1% [51 ± 1.5 mmol/mol]) treated with metformin and long-acting GLP-1R agonists were subjected to two 5-h continuous infusions (separated by a washout period of ≥3 days): one with GIP (6 pmol/kg/min) and another with saline (placebo). After 60 min of infusion, a liquid mixed-meal test was performed, and after 270 min of infusion, an ad libitum meal was served for evaluation of energy intake (primary end point). RESULTS: Energy intake was similar during GIP and placebo infusion (648 ± 74 kcal vs. 594 ± 55 kcal, respectively; P = 0.480), as were appetite measures and energy expenditure. Plasma glucagon and glucose were higher during GIP infusion compared with placebo infusion (P = 0.026 and P = 0.017) as assessed by area under the curve. CONCLUSIONS: In patients with type 2 diabetes, GIP infusion on top of treatment with metformin and a long-acting GLP-1R agonist did not affect energy intake, appetite, or energy expenditure but increased plasma glucose compared with placebo. These results indicate no acute beneficial effects of combining GIP and GLP-1.

Intraperitoneal Treatment of Kisspeptin Suppresses Appetite and Energy Expenditure and Alters Gastrointestinal Hormones in Mice.

BACKGROUND: Kisspeptin is a neuropeptide that plays an integral role in the regulation of energy intake and reproduction by acting centrally on the hypothalamus-pituitary-gonadal axis. Our current study explores for the first time the effects of a pharmacological treatment of intraperitoneal kisspeptin-10 on murine feeding behavior, respirometry parameters, energy balance, and metabolic hormones. METHODS: Two groups (n = 16) of age- and sex-matched C57BL/6 wild-type adult mice were individually housed in metabolic cages and intraperitoneally injected with either kisspeptin-10 (2 nmol in 200 µl of saline) (10 µM) or vehicle before the beginning of a dark-phase cycle. Microstructure of feeding and drinking behavior, respirometry gases, respiratory quotient (RQ), total energy expenditure (TEE), metabolic hormones, oral glucose tolerance, and lipid profiles were measured. RESULTS: Intraperitoneal treatment with kisspeptin-10 caused a significant reduction in food intake, meal frequency, meal size, and eating rate. Kisspeptin-10 significantly decreased TEE during both the dark and light phase cycles, while also increasing the RQ during the dark-phase cycle. In addition, mice injected with kisspeptin-10 had significantly higher plasma levels of insulin (343.8 pg/ml vs. 106.4 pg/ml; p = 0.005), leptin (855.5 pg/ml vs. 173.1 pg/ml; p = 0.02), resistin (9411.1 pg/ml vs. 4116.5 pg/ml; p = 0.001), and HDL (147.6 mg/dl vs 97.1 mg/dl; p = 0.04). CONCLUSION: A pharmacological dose of kisspeptin-10 significantly altered metabolism by suppressing food intake, meal size, eating rate, and TEE while increasing the RQ. These changes were linked to increased levels of insulin, leptin, resistin, and HDL. The current results suggest that a peripheral kisspeptin treatment could alter metabolism and energy homeostasis by suppressing appetite, food intake, and fat accumulation.

Effects of Inulin Propionate Ester Incorporated into Palatable Food Products on Appetite and Resting Energy Expenditure: A Randomised Crossover Study.

Supplementation with inulin-propionate ester (IPE), which delivers propionate to the colon, suppresses ad libitum energy intake and stimulates the release of satiety hormones acutely in humans, and prevents weight gain. In order to determine whether IPE remains effective when incorporated into food products (FP), IPE needs to be added to a widely accepted food system. A bread roll and fruit smoothie were produced. Twenty-one healthy overweight and obese humans participated. Participants attended an acclimatisation visit and a control visit where they consumed un-supplemented food products (FP). Participants then consumed supplemented-FP, containing 10 g/d inulin or IPE for six days followed by a post-supplementation visit in a randomised crossover design. On study visits, supplemented-FP were consumed for the seventh time and ad libitum energy intake was assessed 420 min later. Blood samples were collected to assess hormones and metabolites. Resting energy expenditure (REE) was measured using indirect calorimetry. Taste and appearance ratings were similar between FP. Ad libitum energy intake was significantly different between treatments, due to a decreased intake following IPE-FP. These observations were not related to changes in blood hormones and metabolites. There was an increase in REE following IPE-FP. However, this effect was lost after correcting for changes in fat free mass. Our results suggest that IPE suppresses appetite and may alter REE following its incorporation into palatable food products.

Effects of combined GIP and GLP-1 infusion on energy intake, appetite and energy expenditure in overweight/obese individuals: a randomised, crossover study.

AIMS/HYPOTHESIS: Glucagon-like peptide 1 (GLP-1) reduces appetite and energy intake in humans, whereas the other incretin hormone, glucose-dependent insulinotropic polypeptide (GIP), seems to have no effect on eating behaviour. Interestingly, studies in rodents have shown that concomitant activation of GIP and GLP-1 receptors may potentiate the satiety-promoting effect of GLP-1, and a novel dual GLP-1/GIP receptor agonist was recently shown to trigger greater weight losses compared with a GLP-1 receptor agonist in individuals with type 2 diabetes. The aim of this study was to delineate the effects of combined GIP and GLP-1 receptor activation on energy intake, appetite and resting energy expenditure in humans. METHODS: We examined 17 overweight/obese men in a crossover design with 5 study days. On day 1, a 50 g OGTT was performed; on the following 4 study days, the men received an isoglycaemic i.v. glucose infusion (IIGI) plus saline (154 mmol/l NaCl; placebo), GIP (4 pmol kg-1 min-1), GLP-1 (1 pmol kg-1 min-1) or GIP+GLP-1 (4 and 1 pmol kg-1 min-1, respectively). All IIGIs were performed in a randomised order blinded for the participant and the investigators. The primary endpoint was energy intake as measured by an ad libitum meal after 240 min. Secondary endpoints included appetite ratings and resting energy expenditure, as well as insulin, C-peptide and glucagon responses. RESULTS: Energy intake was significantly reduced during IIGI+GLP-1 compared with IIGI+saline infusion (2715 ± 409 vs 4483 ± 568 kJ [mean ± SEM, n = 17], p = 0.014), whereas there were no significant differences in energy intake during IIGI+GIP (4062 ± 520 kJ) or IIGI+GIP+GLP-1 (3875 ± 451 kJ) infusion compared with IIGI+saline (p = 0.590 and p = 0.364, respectively). Energy intake was higher during IIGI+GIP+GLP-1 compared with IIGI+GLP-1 infusion (p = 0.039). CONCLUSIONS/INTERPRETATION: While GLP-1 infusion lowered energy intake in overweight/obese men, simultaneous GIP infusion did not potentiate this GLP-1-mediated effect. TRIAL REGISTRATION: ClinicalTrials.gov NCT02598791 FUNDING: This study was supported by grants from the Innovation Fund Denmark and the Vissing Foundation.

Gender differences of cannabis smoking on serum leptin levels: population-based study

Objective: To evaluate the serum leptin levels in cannabis smokers. Methods: This was a cross-sectional population-based study of participants between the ages of 18 and 35 years. The data were collected through a self-administered questionnaire covering sociodemographic data and the use of psychoactive substances. Leptin levels were measured using a commercial ELISA kit. Results: Of the 911 participants, 6.7% were identified as cannabis smokers and had significantly lower leptin levels (p = 0.008). When stratified by gender, there was a significant decrease in leptin levels among male smokers (p = 0.039). Conclusion: Cannabis smoking was linked to leptin levels in men, suggesting that the response to biological signals may be different between men and women.

Acute administration of capsaicin increases resting energy expenditure in young obese subjects without affecting energy intake, appetite, and circulating levels of orexigenic/anorexigenic peptides.

Although capsaicin has been reported to reduce energy intake and increase energy expenditure in an adult (normal weight or overweight) population, thus resulting in a net negative energy balance and weight loss, these beneficial effects have not been investigated in young obese subjects. We hypothesize that capsaicin acutely administered in young obese subjects exerts the same effects on energy balance and that these effects are mediated by changes in gastrointestinal peptides regulating appetite. Thus, the aim of the present study was to evaluate the acute effects of capsaicin (2 mg) or placebo on energy intake, hunger, and satiety in obese adolescents and young adults (female-male ratio: 4:6, age: 21.0 ± 5.8 years; body mass index: 41.5 ± 4.3 kg/m2) provided an ad libitum dinner. Furthermore, circulating levels of some orexigenic (ghrelin) and anorexigenic (glucagon-like peptide 1 and peptide YY) peptides were measured after a meal completely consumed (lunch), together with the evaluation of hunger and satiety and assessment of resting energy expenditure (REE) through indirect computerized calorimetry. When compared to placebo, capsaicin did not significantly change either energy intake or hunger/satiety 6 hours after its administration (dinner). No differences in circulating levels of ghrelin, glucagon-like peptide 1, and peptide YY and in hunger/satiety were found in the 3 hours immediately after food ingestion among obese subjects treated with capsaicin or placebo (lunch). By contrast, the meal significantly increased REE in the capsaicin- but not placebo-treated group (capsaicin: from 1957.2 ± 455.1 kcal/d up to 2342.3 ± 562.1 kcal/d, P < .05; placebo: from 2060.1 ± 483.4 kcal/d up to 2296.0 ± 484.5 kcal/d). The pre-post meal difference in REE after capsaicin administration was significantly higher than that observed after placebo (385.1 ± 164.4 kcal/d vs 235.9 ± 166.1 kcal/d, P < .05). In conclusion, although capsaicin does not exert hypophagic effects, these preliminary data demonstrate its ability as a metabolic activator in young obese subjects.

Gender differences of cannabis smoking on serum leptin levels: population-based study.

OBJECTIVE: To evaluate the serum leptin levels in cannabis smokers. METHODS: This was a cross-sectional population-based study of participants between the ages of 18 and 35 years. The data were collected through a self-administered questionnaire covering sociodemographic data and the use of psychoactive substances. Leptin levels were measured using a commercial ELISA kit. RESULTS: Of the 911 participants, 6.7% were identified as cannabis smokers and had significantly lower leptin levels (p = 0.008). When stratified by gender, there was a significant decrease in leptin levels among male smokers (p = 0.039). CONCLUSION: Cannabis smoking was linked to leptin levels in men, suggesting that the response to biological signals may be different between men and women.

Opioidergic and dopaminergic modulation of cost/benefit decision-making in Long Evans Rats.

Eating disorders are associated with impaired decision-making and dysfunctional reward-related neurochemistry. The present study examined the potential contributions of dopamine and opioid signaling to these processes using two different decision-making tasks. In one task, Long Evans Rats chose between working for a preferred food (high-carbohydrate banana-flavored sucrose pellets) by lever pressing on a progressive-ratio schedule of reinforcement vs. obtaining less preferred laboratory chow that was concurrently available. In a second (effort-free) task, rats chose between the same two reinforcers when they were both available freely. Rats were trained in these tasks before receiving haloperidol (0.00, 0.05, 0.10mg/kg, intraperitoneally (i.p.)) or naloxone (0.0, 1.5, 3.0mg/kg, i.p.). In the first task, haloperidol decreased breakpoint, lever presses, number of reinforcers earned, and increased chow intake, whereas naloxone decreased breakpoint and number of reinforcers earned but had no effect on chow consumption. In the effort-free task, haloperidol reduced intakes of both foods without affecting preference, whereas naloxone selectively reduced the consumption of banana-pellets. The present findings support converging evidence suggesting that DA signaling affects processes more closely related to appetitive motivation, leaving other components of motivation unchanged. By contrast, opioid signaling appears to mediate aspects of hedonic feeding by selectively altering intakes of highly palatable foods. For preferred foods, both appetitive and consummatory aspects of food intake were altered by opioid receptor antagonism. Our findings argue against a general suppression of appetite by either compound, as appetite manipulations have been shown to unselectively alter intakes of both types of food regardless of the task employed.

Protein supplements after weight loss do not improve weight maintenance compared with recommended dietary protein intake despite beneficial effects on appetite sensation and energy expenditure: a randomized, controlled, double-blinded trial.

Background: High-protein diets increase weight loss (WL) during energy restriction; therefore, it has been suggested that additional protein intake may improve weight maintenance (WM) after WL.Objective: We investigated the effect of protein supplements from either whey with or without calcium or soy on WM success after WL compared with that of a control.Design: In a randomized, controlled, double-blinded trial, 220 participants aged 18-60 y with body mass index (in kg/m2) from 27.6 to 40.4 were included. The study was initiated with an 8-wk WL period followed by a 24-wk WM period. During WM, participants consumed the following isocaloric supplements (45-48 g/d): whey and calcium (whey+), whey, soy, or maltodextrin (control). Data were collected at baseline, before WM, and after WM (weeks 0, 8, and 32, respectively) and included body composition, blood biochemistry, and blood pressure. Meal tests were performed to investigate diet-induced-thermogenesis (DIT) and appetite sensation. Compliance was tested by 24-h urinary nitrogen excretion.Results: A total of 151 participants completed the WM period. The control and 3 protein supplements did not result in different mean ± SD weight regains (whey+: 2.19 ± 4.6 kg; whey: 2.01 ± 4.6 kg; soy: 1.76 ± 4.7 kg; and control: 2.23 ± 3.8 kg; P = 0.96), fat mass regains (whey+: 0.46 ± 4.5 kg; whey: 0.11 ± 4.1 kg; soy: 0.15 ± 4.1 kg; and control: 0.54 ± 3.3 kg; P = 0.96), or improvements in lean body mass (whey+: 1.87 ± 1.7 kg; whey: 1.94 ± 1.3 kg; soy: 1.58 ± 1.4 kg; and control: 1.74 ± 1.4 kg; P = 0.50) during WM. Changes in blood pressure and blood biochemistry were not different between groups. Compared with the control, protein supplementation resulted in higher DIT (∼30 kJ/2.5 h) and resting energy expenditure (243 kJ/d) and an anorexigenic appetite-sensation profile.Conclusion: Protein supplementation does not result in improved WM success, or blood biochemistry after WL compared with the effects of normal dietary protein intake (0.8-1.0 g · kg-1 · d-1). This trial was registered at clinicaltrials.gov as NCT01561131.

Effects of Dietary Protein Source and Quantity during Weight Loss on Appetite, Energy Expenditure, and Cardio-Metabolic Responses.

Higher protein meals increase satiety and the thermic effect of feeding (TEF) in acute settings, but it is unclear whether these effects remain after a person becomes acclimated to energy restriction or a given protein intake. This study assessed the effects of predominant protein source (omnivorous, beef/pork vs. lacto-ovo vegetarian, soy/legume) and quantity (10%, 20%, or 30% of energy from protein) on appetite, energy expenditure, and cardio-metabolic indices during energy restriction (ER) in overweight and obese adults. Subjects were randomly assigned to one protein source and then consumed diets with different quantities of protein (4 weeks each) in a randomized crossover manner. Perceived appetite ratings (free-living and in-lab), TEF, and fasting cardio-metabolic indices were assessed at the end of each 4-week period. Protein source and quantity did not affect TEF, hunger, or desire to eat, other than a modestly higher daily composite fullness rating with 30% vs. 10% protein diet (p = 0.03). While the 20% and 30% protein diets reduced cholesterol, triacylglycerol, and APO-B vs. 10% protein (p < 0.05), protein source did not affect cardio-metabolic indices. In conclusion, diets varying in protein quantity with either beef/pork or soy/legume as the predominant source have minimal effects on appetite control, energy expenditure and cardio-metabolic risk factors during ER-induced weight loss.

Effect of Oxyntomodulin, Glucagon, GLP-1, and Combined Glucagon +GLP-1 Infusion on Food Intake, Appetite, and Resting Energy Expenditure.

CONTEXT: The gut hormone, oxyntomodulin, is a proglucagon product with body weight-lowering potential. It binds to both the glucagon-like peptide-1 (GLP-1) receptor and the glucagon receptor; however, the mechanism behind the body weight-lowering effect remains elusive. OBJECTIVE: We wanted to delineate the contributions of separate and combined GLP-1 receptor and glucagon receptor activation to the body weight-reducing mechanisms of oxyntomodulin. DESIGN: This was a double-blinded, randomized, crossover study. SETTING: The study was conducted at a specialized research unit. PARTICIPANTS: Fifteen young healthy male volunteers (aged 22 [range 18-32] y; body mass index 23 [21-26] kg/m(2); fasting plasma glucose 5.1 [4.4-5.4] mmol/L; and glycated hemoglobin A1c 40 (37-42) mmol/mol). INTERVENTIONS: Five 4-hour liquid meal tests during the infusion of saline, GLP-1 (1 pmol × kg(-1) × min(-1)), glucagon (0.86 pmol × kg(-1) × min(-1)), oxyntomodulin (3 pmol × kg(-1) × min(-1)), or glucagon+GLP-1 (same doses). MAIN OUTCOME MEASURES: We evaluated resting energy expenditure (measured as oxygen uptake, gastric emptying (GE), composite appetite scores (CAS), and food intake. RESULTS: Oxyntomodulin, GLP-1, and GLP-1+glucagon slowed GE and reduced CAS, whereas glucagon did not affect GE and CAS. All infusions caused a similar decrease in food intake compared with saline (total intake (g [95% confidence interval]), saline 811 [729, 892], GLP-1 669 [586, 750], glucagon 686 [604, 768], oxyntomodulin 689 [608, 771], and glucagon+GLP-1 688 [606, 769]). Oxygen uptake did not change significantly from baseline in response to any peptide infusion compared with saline. CONCLUSIONS: Oxyntomodulin, GLP-1, and glucagon decreased food intake but with no additional effect of combining GLP-1 and glucagon.

Brief versions of the FACIT-fatigue and FAACT subscales for patients with non-small cell lung cancer cachexia.

PURPOSE: Cancer anorexia-cachexia syndrome (CACS) is common in advanced cancer patients and associated with weight loss, fatigue, impaired quality of life (QoL), and poor prognosis. The goal of this project was to identify the most responsive items from two QoL measures in the ROMANA 2 (NCT01387282) phase III global study evaluating anamorelin HCl in the treatment of non-small cell lung cancer (NSCLC) cachexia: the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) and the Functional Assessment of Anorexia/Cachexia Therapy (FAACT). METHODS: In the ROMANA 2 trial, 477 patients with unresectable stage III or IV NSCLC and cachexia were to be enrolled and randomized (2:1) to receive anamorelin HCl or placebo once daily for 12 weeks. All 203 patients who reached the week 12 visit at the time of data analysis were included. Co-primary endpoints were change from baseline in lean body mass and handgrip strength. QoL was a secondary outcome with FACIT-F and FAACT questionnaires administered at baseline and at weeks 3, 6, 9, and 12. RESULTS: Two 4-item scales (fatigue/activity and appetite/eating) from the FACIT-F and FAACT questionnaires, respectively, demonstrated good internal consistency reliability, validity, and responsiveness (also referred to as the Simplified Evaluation of Fatigue (SEF) and Simplified Evaluation of Appetite (SEA), respectively). The estimated important difference for each scale was 1-2 points. CONCLUSIONS: These brief scales provide the psychometric properties necessary to promote future research in NSCLC patients with CACS. Additional work should examine the clinical utility of these scales and their impact on treatment decision-making.

Sucrose compared with artificial sweeteners: a clinical intervention study of effects on energy intake, appetite, and energy expenditure after 10 wk of supplementation in overweight subjects.

BACKGROUND: There is a lack of appetite studies in free-living subjects supplying the habitual diet with either sucrose or artificially sweetened beverages and foods. Furthermore, the focus of artificial sweeteners has only been on the energy intake (EI) side of the energy-balance equation. The data are from a subgroup from a 10-wk study, which was previously published. OBJECTIVE: The objective was to investigate changes in EI and energy expenditure (EE) as possible reasons for the changes in body weight during 10 wk of supplementation of either sucrose or artificial sweeteners in overweight subjects. DESIGN: Supplements of sucrose-sweetened beverages and foods (2 g/kg body weight; n = 12) or similar amounts containing artificial sweeteners (n = 10) were given single-blind in a 10-wk parallel design. Beverages accounted for 80% and solid foods for 20% by weight of the supplements. The rest of the diet was free choice. Indirect 24-h whole-body calorimetry was performed at weeks 0 and 10. At week 0 the diet was a weight-maintaining standardized diet. At week 10 the diet consisted of the supplements and ad libitum choice of foods. Visual analog scales were used to record appetite. RESULTS: Body weight increased in the sucrose group and decreased in the sweetener group during the intervention. The sucrose group had a 3.3-MJ higher EI but felt less full and had higher ratings of prospective food consumption than did the sweetener group at week 10. Basal metabolic rate was increased in the sucrose group, whereas 24-h EE was increased in both groups at week 10. Energy balance in the sucrose group was more positive than in the sweetener group at the stay at week 10. CONCLUSION: The changes in body weight in the 2 groups during the 10-wk intervention seem to be attributable to changes in EI rather than to changes in EE.

Effects of PYY3-36 and GLP-1 on energy intake, energy expenditure, and appetite in overweight men.

Our aim was to examine the effects of GLP-1 and PYY3-36, separately and in combination, on energy intake, energy expenditure, appetite sensations, glucose and fat metabolism, ghrelin, and vital signs in healthy overweight men. Twenty-five healthy male subjects participated in this randomized, double-blinded, placebo-controlled, four-arm crossover study (BMI 29 ± 3 kg/m(2), age 33 ± 9 yr). On separate days they received a 150-min intravenous infusion of 1) 0.8 pmol·kg(-1)·min(-1) PYY3-36, 2) 1.0 pmol·kg(-1)·min(-1) GLP-1, 3) GLP-1 + PYY3-36, or 4) placebo. Ad libitum energy intake was assessed during the final 30 min. Measurements of appetite sensations, energy expenditure and fat oxidation, vital signs, and blood variables were collected throughout the infusion period. No effect on energy intake was found after monoinfusions of PYY3-36 (-4.2 ± 4.8%, P = 0.8) or GLP-1 (-3.0 ± 4.5%, P = 0.9). However, the coinfusion reduced energy intake compared with placebo (-30.4 ± 6.5%, P < 0.0001) and more than the sum of the monoinfusions (P < 0.001), demonstrating a synergistic effect. Coinfusion slightly increased sensation of nausea (P < 0.05), but this effect could not explain the effect on energy intake. A decrease in plasma ghrelin was found after all treatments compared with placebo (all P < 0.05); however, infusions of GLP-1 + PYY3-36 resulted in an additional decrease compared with the monoinfusions (both P < 0.01). We conclude that coinfusion of GLP-1 and PYY3-36 exerted a synergistic effect on energy intake. The satiating effect of the meal was enhanced by GLP-1 and PYY3-36 in combination compared with placebo. Coinfusion was accompanied by slightly increased nausea and a decrease in plasma ghrelin, but neither of these factors could explain the reduction in energy intake.

The effects of second-generation antipsychotics on food intake, resting energy expenditure and physical activity.

Second-generation antipsychotics (SGA) are associated with weight gain and metabolic alterations including hyperglycemia, dyslipidemia, hypertension and metabolic syndrome. These metabolic side effects increase cardiovascular risk and are related to medication non-compliance. Patients without previous exposure to these or other antipsychotic drugs (naive patients) seem to be more prone to develop these metabolic abnormalities. The mechanisms behind weight gain can be an increase in food intake and/or a decrease in energy expenditure. This review comprehensively examines the current knowledge on the impact of these drugs on food intake and energy expenditure. The influence of these drugs on appetite and food intake (total caloric intake and food sources) is reviewed as well as the evidence of abnormal eating behaviors. The studies evaluating the effect on resting energy expenditure are critically examined, taking into account the influence of body composition and previous exposure to antipsychotics (naive vs non-naive patients). Finally, the influence of these drugs on physical activity is also discussed. The knowledge of the mechanisms of weight gain in patients starting these drugs may be useful to further prompt research in this field and ameliorate the metabolic side effects associated with these treatments.

Night-time consumption of protein or carbohydrate results in increased morning resting energy expenditure in active college-aged men.

The purpose of the present study was to investigate whether whey protein (WP), casein protein (CP), carbohydrate (CHO) or a non-energy-containing placebo (PLA) consumed before sleep alters morning appetite and resting energy expenditure (REE) in active men. A total of eleven men (age: 23·6 (sem 1·0) years; body fat: 16·3 (sem 2·5) %) participated in this randomised, double-blind, cross-over study. A single dose of WP (30 g), CP (30 g), CHO (33 g) or PLA was consumed 30 min before sleep, and each trial was separated by 48-72 h. The next morning (05.00-08.00 hours), measurements of satiety, hunger and desire to eat and REE were taken. After a 30 min equilibration period, REE in the supine position was measured for 60 min. An analysis of 10 min mean intervals over the final 50 min of the measurement period was conducted. Statistical analyses were conducted using repeated-measures ANOVA for metabolic variables, and a one-way ANOVA was used for measuring changes in appetite markers. Group differences were examined by Tukey's post hoc analysis. There were no significant differences in appetite measures among the groups. There was a main group effect for REE. The predicted REE was significantly greater after consumption of the WP (8151 (sem 67) kJ/d), CP (8126 (sem 67) kJ/d) and CHO (7988 (sem 67) kJ/d) than after that of the PLA (7716 (sem 67) kJ/d, P <0·0001). There were no significant differences between the WP and CP groups in any metabolic measurements. Night-time consumption of WP, CP or CHO, in the hours close to sleep, elicits favourable effects on the next-morning metabolism when compared with that of a PLA in active young men.

The effect of agar jelly on energy expenditure, appetite, gastric emptying and glycaemic response.

BACKGROUND AND PURPOSE: Agar contains a high amount of soluble fibre and has been shown to delay gastric emptying (GE) without impacting on glycaemic response (GR). The current study aimed to further the limited data on the effect of agar on metabolism by assessing the effects on GE and GR as well as appetite- and diet-induced thermogenesis (DIT). METHODS: In this randomized control trial, eleven healthy volunteers were tested on two occasions following an overnight fast. Following baseline and resting measurements, volunteers were either fed a fruit-flavoured drink (liquid) or consumed a fruit-flavoured jelly (jelly). The two were exactly the same in composition except the jelly contained 4 g of agar crystals. Both contained 50 g of available carbohydrate. DIT was measured using indirect calorimetry, GE using the (13)C sodium acetate breath test, appetite using visual analogue scale and GR using finger prick blood samples. RESULTS: The jelly significantly delayed GE across all time points-latency phase (p = 0.07), lag phase (p = 0.04), half-time (p < 0.0001), ascension time (p = 0.025). The jelly also increased all appetite parameters-hunger (p = 0.006), fullness (p = 0.035), desire to eat (p = 0.03) and prospective consumption (p = 0.011). However, there were no significant differences in either GR or postprandial DIT between the liquid and jelly. CONCLUSION: Agar delays GE and increases appetite but does not change GR or DIT most probably due to the increase in viscosity caused by the agar jelly.

Effect of dairy proteins on appetite, energy expenditure, body weight, and composition: a review of the evidence from controlled clinical trials.

Evidence supports that a high proportion of calories from protein increases weight loss and prevents weight (re)gain. Proteins are known to induce satiety, increase secretion of gastrointestinal hormones, and increase diet-induced thermogenesis, but less is known about whether various types of proteins exert different metabolic effects. In the Western world, dairy protein, which consists of 80% casein and 20% whey, is a large contributor to our daily protein intake. Casein and whey differ in absorption and digestion rates, with casein being a "slow" protein and whey being a "fast" protein. In addition, they differ in amino acid composition. This review examines whether casein, whey, and other protein sources exert different metabolic effects and targets to clarify the underlying mechanisms. Data indicate that whey is more satiating in the short term, whereas casein is more satiating in the long term. In addition, some studies indicate that whey stimulates the secretion of the incretin hormones glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide more than other proteins. However, for the satiety (cholecystokinin and peptide YY) and hunger-stimulating (ghrelin) hormones, no clear evidence exists that 1 protein source has a greater stimulating effect compared with others. Likewise, no clear evidence exists that 1 protein source results in higher diet-induced thermogenesis and promotes more beneficial changes in body weight and composition compared with other protein sources. However, data indicate that amino acid composition, rate of absorption, and protein/food texture may be important factors for protein-stimulated metabolic effects.

AMPK and the neuroendocrine regulation of appetite and energy expenditure.

This review highlights recent advances in the hormonal control of hypothalamic AMPK activity and the impact on appetite and energy metabolism. AMPK is an intracellular energy sensor that switches off ATP-consuming pathways and switches on ATP-producing pathways such as glucose uptake and fatty acid oxidation. In this regard, it is well positioned to respond to dynamic changes in metabolic state and nutritional over- or under-supply. Within the hypothalamus, AMPK responds to peripheral hormones that convey metabolic information based on increased plasma concentrations. For example, negative energy balance increases plasma ghrelin concentrations, increases hypothalamic AMPK and drives food intake. Conversely, plasma leptin concentrations are secreted in proportion to adipose levels and leptin suppresses hypothalamic AMPK activity and restricts food intake. This review explains that hypothalamic AMPK mediates neuroendocrine feedback control of energy metabolism. A current working model suggests that endocrine feedback influences hypothalamic AMPK via a number of mechanisms designed to shift an organism from negative to neutral energy balance. These mechanisms include (1) ghrelin stimulation of AMPK in NPY/AgRP in the arcuate nucleus (2) ghrelin stimulation of AMPK in the ventromedial hypothalamic nucleus, (3) a novel ghrelin-stimulated AMPK-dependent presynaptic mechanism that sustains AgRP neuron firing via a local synaptic memory system, (4) adiponectin stimulation of hypothalamic AMPK and (5) hypothalamic AMPK control of energy expenditure by thyroid hormone or leptin. The number of diverse mechanisms ensures hypothalamic AMPK drives the shift from negative to neutral energy balance and underscores the fundamental importance of hypothalamic AMPK to maintain neutral energy balance.