Subjective Appetite Sensations Research Articles

Effect of breakfast omission on subjective appetite, metabolism, acylated ghrelin and GLP-17-36 during rest and exercise

ObjectivesBreakfast omission induces compensatory eating behaviour at lunch, but often reduces daily energy intake. This study investigated the effect of breakfast omission on within-day subjective appetite, energy expenditure, substrate utilisation, and appetite hormone profiles, in response to standardised feeding and exercise. MethodsEight male, habitual breakfast eaters completed two randomised trials. Subjects arrived overnight fasted (0 h), and either consumed (BC) or omitted (BO) a standardized breakfast (mean standard deviation [SD]) (3085 [217] kJ). Lunch (4162 [510] kJ) and dinner (4914 [345] kJ) were provided at 4.5 and 10 h, respectively and subjects performed 60 min fixed-intensity cycling (50% VO2 peak) at 8 h. Blood samples were collected at 0, 4.5, 6, and 8 h, with expired air and subjective appetite sensations (hunger, fullness, desire to eat (DTE), and prospective food consumption [PFC]) collected throughout. Heart rate and perceived exertion were measured during exercise. ResultsHunger, DTE and PFC were greater and fullness lower during BO (P < 0.05) between breakfast and lunch, with no differences after lunch (P > 0.193). Resting energy expenditure was greater at 2.5 h during BC (P < 0.05) with no other differences between trials (P > 0.156). Active glucogon-like peptide-1 (GLP-17-36) was greater (P < 0.05) and acylated ghrelin tended to be greater (P = 0.078) at 4.5 h during BC. Heart rate was greater on BO (P < 0.05) during exercise. ConclusionsThe results of this laboratory-controlled study suggest that the effects of breakfast omission are transient and do not extend beyond lunch, even when the negative energy balance created by breakfast omission is sustained via standardised feeding and exercise.

The effect of a whey protein supplement dose on satiety and food intake in resistance training athletes

Objective: Many athletes perform resistance training and consume dietary protein as a strategy to promote anabolic adaptation. Due to its high satiety value, the regular addition of supplemented dietary protein could plausibly displace other key macronutrients such as carbohydrate in an athlete's diet. This effect will be influenced by the form and dose of protein. Therefore, this study assessed the impact of liquid whey protein dose manipulation on subjective sensations of appetite and food intake in a cohort of athletes. Design: Ten male athletes who performed both resistance and aerobic (endurance) training (21.2 ± 2.3 years; 181.7 ± 5.7 cm and 80.8 ± 6.1 kg) were recruited. In four counter-balanced testing sessions they consumed a manipulated whey protein supplement (20, 40, 60 or 80 g protein) 1 hour after a standardised breakfast. Subsequent energy intake was measured 3 hours after the protein supplement using an ad libitum test meal. Subjective appetite sensations were measured periodically during the test day using visual analogue scales. Results: All conditions resulted in a significant decrease in ratings of hunger (50–65%; P < 0.05) at the time of supplement consumption. However, there were no significant differences between the conditions at any time point for subjective appetite sensations or for energy consumed in the ad libitum meal: 4382 ± 1004, 4643 ± 982, 4514 ± 1112, 4177 ± 1494 kJ respectively. Conclusion: Increasing whey protein supplement dose above 20 g did not result in a measurable increase in satiety or decrease in food intake. However, the inclusion of additional whey protein supplementation where not otherwise consumed could plausibly reduce dietary intake.

비기허증(脾氣虛證) 환자의 식사 전후 주관적 식욕과 Gut Hormone 혈중 농도에 대한 탐색적 연구

Objectives The aim of this study was to investigate clinical factors of SQD syndrome by tracking plasma gut hormone (active ghrelin, active Glucagon-like peptide-1(GLP-1), pancreatic polypeptide(PP), total peptide YY(PYY)) profiling of pre-post prandial standard meal between SQD group and normal group. Methods A total of 24 adult participants were consecutively recruited on April 2014. They were diagnosed as either by SQD syndrome or normal by Spleen Qi Deficiency Questionnaire (SQDQ). On the experimental day, blood samplings of 2 ml were repeatedly collected at 6 points from 2 groups for measuring plasma levels of gut hormones. At every point, subjective appetite sensations were self-registered. Results & Conclusions 1. There were significantly lower subjective 'Appetite' (p=0.012) and higher 'Satiety' (p=0.012) in SQD group. At each time point, subjective 'Appetite' was significantly lower at 60 min after breakfast (p=0.034) and 'Satiety' were significantly higher at 15 min (p=0.020) and 120 min (p=0.044) after breakfast in SQD group. 2. There were no significant differences in plasma levels of gut hormones (active ghrelin, active GLP-1, PP, total PYY) between SQD and normal group. Also at each time point, there were no significant differences of plasma levels of gut hormones between SQD and normal group. 3. Changes in plasma levels of gut hormones compared to baseline were not significantly different at each time point between SQD and normal group. Plasma PYY levels compared to baseline increased in SQD group following 15 min and 30 min after breakfast but decreased in normal group. 4. Further investigation is needed to construct gut hormone profiling and in this perspective, we can approach evaluation tool on variable appetite in Traditional Korean Medicine (TKM) syndrome in the future.

Fasting gut hormone levels change with modest weight loss in obese adolescents.

Gut hormones change with weight loss in adults but are not well studied in obese youth. The primary aim was to evaluate how gut hormones and subjective appetite measure change with dietary weight loss in obese adolescents. Participants were a subset of those taking part in the 'Eat Smart Study'. They were aged 10-17 years with body mass index (BMI) > 90th centile and were randomized to one of three groups: wait-listed control, structured reduced carbohydrate or structured low-fat dietary intervention for 12 weeks. Outcomes were fasting glucose, insulin, leptin, adiponectin, total amylin, acylated ghrelin, active glucagon-like peptide-1, glucose-dependent insulinotropic polypeptide (GIP), pancreatic polypeptide (PP) and total peptide tyrosine-tyrosine. Pre- and postprandial subjective sensations of appetite were assessed using visual analogue scales. Of 87 'Eat Smart' participants, 74 participated in this sub-study. The mean (standard deviation) BMI z-score was 2.1 (0.4) in the intervention groups at week 12 compared with 2.2 (0.4) in the control group. Fasting insulin (P = 0.05) and leptin (P = 0.03) levels decreased, while adiponectin levels increased (P = 0.05) in the intervention groups compared with control. The intervention groups were not significantly different from each other. A decrease in BMI z-score at week 12 was associated with decreased fasting insulin (P < 0.001), homeostatic model of assessment-insulin resistance (P < 0.001), leptin (P < 0.001), total amylin (P = 0.03), GIP (P = 0.01), PP (P = 0.02) and increased adiponectin (P < 0.001). There was no significant difference in appetite sensations. Modest weight loss in obese adolescents leads to changes in some adipokines and gut hormones that may favour weight regain.

Four weeks supplementation with Lactobacillus paracasei subsp. paracasei L. casei W8® shows modest effect on triacylglycerol in young healthy adults.

The microbiota has been shown to have the potential to affect appetite and blood lipids positively in animal studies. We investigated if four weeks supplementation with Lactobacillus paracasei subsp. paracasei L. casei W8® (L. casei W8) had an effect on subjective appetite sensation, ad libitum energy intake, glucagon-like peptide 1 (GLP-1), glucose and insulin response in humans. Secondarily, we explored potential effects on blood lipids, fatty acids and stearoyl-CoA desaturase-1 (SCD1) activity in humans as well as SCD1 expression in piglets given L. casei W8 for two weeks. 64 healthy participants completed the double-blinded, randomised, controlled, parallel four weeks study with supplementation of L. casei W8 (1010 cfu) or placebo capsules. A meal test was conducted before and after the intervention, where subjective appetite, ad libitum energy intake, GLP-1, glucose and insulin response were measured. Additionally fasting blood lipids and fatty acids concentrations were measured. Sixteen piglets were randomised into two groups: L. casei W8 (1010 cfu/day) as top dressing on morning fed or no treatment. After two weeks piglets were sacrificed and tissue from ileum, jejunum and skeletal muscle were sampled for mRNA analyses of SCD1 expression. Compared to placebo, L. casei W8 did not affect appetite, ad libitum energy intake, GLP-1, glucose and insulin response and total, high-density or low-density lipoprotein cholesterol levels after four weeks intervention. Triacylglycerol decreased in the L. casei W8 group compared to placebo at week 4 (P=0.03). The C16:1n-7/C16:0 ratio, reflecting SCD1 activity, tended to decrease when having L. casei W8 (P=0.06) compared to placebo. Muscle SCD1 expression decreased in piglets supplemented with L. casei W8 compared to control. In conclusion, supplementation with L. casei W8 did not affect appetite parameters, glucose or insulin responses; but appear to be able to lower triacylglycerol levels, possibly by reducing its production.

Satiety effects of a whole-grain fibre composite ingredient: reduced food intake and appetite ratings

The current study assesses the impact on appetite and food intake of a novel co-processed ingredient containing a viscous fibre and whole-grain high-amylose corn flour, a source of type 1 and type 2 resistant starch (HAM-RS). Ninety adults completed a crossover, placebo-controlled study comparing two doses of the ingredient (20 and 30 g) to a maltodextrin control in a fruit-based smoothie served with breakfast. Ad libitum food intake was measured over the day and visual analogue scales were used to assess subjective appetite sensations. Subjects consumed 7% less energy intake at dinner following the 30 g dose (p = 0.02) compared to control. In addition, a trend for lower lunch intake (5% less weight of food) was observed for the 20 g dose (p = 0.10). Reductions were also observed for the two meals combined, with 3% lower energy intake for the 20 g dose (p = 0.04) and 5% less weight of food consumed for the 30 g dose (p = 0.04). Lower ratings of hunger were reported at 3 h after breakfast for both doses and also at 2 and 3 h after lunch for the 30 g dose. With ratings combined to compute an overall appetite score, a trend for lower appetite scores at 3 h after breakfast was found for both doses. Consistent with this, significant reductions in AUC hunger and prospective consumption were identified in the 30 g condition. A similar pattern of results was observed for fullness and desire to eat. The results of this study show that a new composite satiety ingredient comprised of a viscous fibre and whole-grain corn flour can affect acute satiety responses in men and women.

Lactobacillus paracasei subsp paracasei L. casei W8 suppresses energy intake acutely

Background: Probiotic bacteria have been shown to have various effects on the microbiota; this may also affect appetite and may help promote weight loss and maintenance. Objective: This study was conducted to investigate the effect of Lactobacillus paracasei subsp paracasei L. casei W8 (L. casei W8) on glucagon-like peptide-1 (GLP-1) responses in an isolated pig intestine, in piglets and postprandially in humans. Additionally, the effect on subjective appetite, ad libitum energy intake, and glucose and insulin responses in humans was investigated. Design: Piglets were fed with probiotics for 2 weeks and the effect on glucagon encoding gene (GCG) was investigated. An isolated pig intestine was perfused with L. casei W8 and the GLP-1 response was measured. Twenty-one subjects completed a randomized, controlled, crossover study with three arms. Each participant completed 3 test days testing the effect of low dose (LD) (109 CFU), high dose (HD) (1010 CFU) L. casei W8 or placebo capsule. Subjective appetite was assessed before an ad libitum lunch was served. GLP-1, insulin and glucose concentrations were analyzed. Results: Two weeks of treatment of piglets with L. casei W8 resulted in an increase in GCG expression compared to control animals (P < 0.05). L. casei W8 increased the GLP-1 response in the isolated pig intestine. In humans, L. casei W8 had an overall effect on energy intake (P = 0.03), but no effects on subjective appetite sensation, overall glucose and insulin response and on GLP-1 release were observed (P > 0.1). Conclusion: The probiotic bacteria L. casei W8 appears to lower food intake acutely, but the underlying mechanisms are not understood.

Second meal effect on appetite and fermentation of wholegrain rye foods

Background: Wholegrain rye has been associated with decreased hunger sensations. This may be partly mediated by colonic fermentation. Sustained consumption of fermentable components is known to change the gut microflora and may increase numbers of saccharolytic bacteria. Objective: To investigate the effect of wholegrain rye consumption on appetite and colonic fermentation after a subsequent meal. Methods: In a randomized, controlled, three-arm cross-over study, twelve healthy male subjects consumed three iso-caloric evening test meals. The test meals were based on white wheat bread (WBB), wholegrain rye kernel bread (RKB), or boiled rye kernels (RK). Breath hydrogen excretion and subjective appetite sensation were measured before and at 30 min intervals for 3 h after a standardized breakfast in the subsequent morning. After the 3 h, an ad libitum lunch meal was served to assess energy intake. In an in vitro study, RKB and RK were subjected to digestion and 24 h-fermentation in order to study SCFA production and growth of selected saccharolytic bacteria. Results: The test meals did not differ in their effect on parameters of subjective appetite sensation the following day. Ad libitum energy intake at lunch was, however, reduced by 11% (P < 0.01) after RKB and 7% (P < 0.05) after RK compared with after WWB evening meal. Breath hydrogen excretion was significantly increased following RKB and RK evening meals compared with WWB (P < 0.01 and P < 0.05, respectively). Overall, RKB and RK were readily fermented in vitro and exhibited similar fermentation profiles, although total SCFA production was higher for RK compared with RKB (P < 0.001). In vitro fermentation of RKB and RK both increased the relative quantities of Bifidobacterium and decreased Bacteroides compared with inoculum (P < 0.001). The C. coccoides group was reduced after RKB (P < 0.001). Conclusion: Consumption of wholegrain rye products reduced subsequent ad libitum energy intake in young healthy men, possibly mediated by mechanisms related to colonic fermentation.

Intravenous catheterization and the clinical setting do not impact appetite sensations in children (393.4)

In the clinical setting children report intravenous procedures as distressing but it is unknown if they affect their appetite sensations. Therefore, the objective of this study was to evaluate the effect of setting and venous blood draws on subjective appetite (SA) and physical comfort (PC) in children. Methods: In two separate studies, 9‐14 y children (5th‐85th BMI percentile) consumed a snack of either yogurt or cookies in random order. One study was conducted non‐invasively at a university laboratory (n=23) and another study was conducted at the hospital (n=11) where children had an intravenous catheter inserted for repeated blood draws over 2 h. In both studies, food intake (FI) was measured at an ad libitum meal 120 min after the snack. SA and PC were measured at 0, 30, 45, 60, 90, 120 and 145 min using visual analogue scale questionnaires. Results: There was no difference between settings for the baseline SA and PC scores. There was an effect of time, but not setting, on two hour average appetite (P&lt;0.01). Children had slightly higher PC scores (12%) in the clinical setting (P&lt;0.01) but PC did not correlate with SA scores or FI in any setting. PC scores were high (0‐100 mm scale) in both the clinical setting (82 mm ± 1.8) and university setting (72 mm ± 1.2) indicating a lack of effect of setting and catheterization on appetite sensations. Conclusion: Venous blood draws performed in the clinical setting do not affect subjective appetite sensations following snacks in children.Grant Funding Source: Supported by Dairy Farmers of Canada

The influence of calcium supplementation on substrate metabolism during exercise in humans: a randomized controlled trial

High calcium intakes enhance fat loss under restricted energy intake. Mechanisms explaining this may involve reduced dietary fat absorption, enhanced lipid utilization and (or) reductions in appetite. This study aimed to assess the impact of 2 weeks of calcium supplementation on substrate utilization during exercise and appetite sensations at rest. Thirteen physically active males completed two 14-d supplemental periods, in a double-blind, randomized crossover design separated by a ⩾4-week washout period. During supplementation, a test-drink was consumed daily containing 400 and 1400 mg of calcium during control (CON) and high-calcium (CAL) periods, respectively. Cycling-based exercise tests were conducted before and after each supplemental period to determine substrate utilization rates and circulating metabolic markers (non-esterified fatty acid, glycerol, glucose and lactate concentrations) across a range of exercise intensities. Visual analog scales were completed in the fasting, rested state to determine subjective appetite sensations. No significant differences between supplements were observed in lipid or carbohydrate utilization rates, nor in circulating metabolic markers (both P>0.05). Maximum rates of lipid utilization were 0.47±0.05 and 0.44±0.05 g/min for CON and CAL, respectively, prior to supplementation and 0.44±0.05 and 0.42±0.05 g/min, respectively, post-supplementation (main effects of time, supplement and time x supplement interaction effect all P>0.05). Furthermore, no significant differences were detected in any subjective appetite sensations (all P>0.05). Two weeks of calcium supplementation does not influence substrate utilization during exercise in physically active males.

Appetite sensations and substrate metabolism at rest, during exercise, and recovery: impact of a high-calcium meal

The aim of this study was to investigate the effects of the calcium content of a high-carbohydrate, pre-exercise meal on substrate metabolism and appetite sensations before, during, and after exercise. Nine active males participated in 2 trials in a double-blind, randomised, crossover design. After consuming a high carbohydrate (1.5 g · kg(-1) of body mass) breakfast with a calcium content of either 3 (control trial) or 9 mg · kg(-1) of body mass (high milk-calcium (CAL)), participants ran at 60% peak oxygen uptake for 60 min. Following exercise, a recovery drink was consumed and responses were investigated for a further 90 min. Blood and expired gas were sampled throughout to determine circulating substrate and hormone concentrations and rates of substrate oxidation. Visual analogue scales were also administered to determine subjective appetite sensations. Neither whole-body lipid oxidation nor non-esterified fatty acid availability differed between trials. The area under the curve for the first hour following breakfast consumption was 16% (95% confidence interval: 0%-35%) greater for fullness and 10% (95% confidence interval: 2%-19%) greater for insulin in the CAL trial but these differences were transient and not apparent later in the trial. This study demonstrates that increasing the calcium content of a high carbohydrate meal transiently increases insulinemia and fullness but substrate metabolism is unaffected.

Agreement between paper and pen visual analogue scales and a wristwatch-based electronic appetite rating system (PRO-Diary[formula omitted]), for continuous monitoring of free-living subjective appetite sensations in 7–10 year old children

Electronic capture of free-living subjective appetite data can provide a more reliable alternative to traditional pen and paper visual analogue scales (P&P VAS), whilst reducing researcher workload. Consequently, the aim of this study was to explore the agreement between P&P VAS and a wristwatch-based electronic appetite rating system known as the PRO-Diary© technique, for monitoring free-living appetite sensations in 7–10year old children. On one occasion, using a within-subject design, the 12 children (n=6 boys; n=6 girls) recorded their subjective appetite (hunger, prospective food consumption, and fullness), at two time points before lunch (11:30 and 12:00) and every 60min thereafter until 21:00. The agreement between the P&P VAS and PRO-Diary© technique was explored using 95% limits of agreement and 95% confidence intervals (95% CI) calculated using the Bland and Altman (1986) technique. For hunger, prospective food consumption and fullness, the 95% limits of agreement were −1±25mm (95% CI: lower limit −8mm; upper limit +6mm), 0±21mm (95% CI: lower limit −6mm; upper limit +6mm) and −6±24mm (95% CI: lower limit −14mm; upper limit +1mm), respectively. Given the advantages associated with electronic data capture (inexpensive; integrated alarm; data easily downloaded), we conclude that the PRO-Diary© technique is an equivalent method to employ when continuously monitoring free-living appetite sensations in 7–10year old children, but should not be used interchangeably with P&P VAS.

Calcium co-ingestion augments postprandial glucose-dependent insulinotropic peptide1–42, glucagon-like peptide-1 and insulin concentrations in humans

This study determined whether calcium co-ingestion potentiates postprandial GIP(1-42) and GLP-1 concentrations in humans and the concomitant impact on insulin, appetite sensations and substrate metabolism. Ten healthy males consumed two energy- and macronutrient-matched meals in a double-blind, randomized, crossover design. The calcium content of the control meal was 3 mg/kg body mass, which was increased to 15 mg/kg body mass with calcium co-ingestion. Circulating concentrations of GIP(1-42), GLP-1 and insulin were determined over a 180-min postprandial period, followed by 60 min of exercise. Visual analogue scales were used to determine subjective appetite sensations. Rates of energy expenditure and substrate (lipid and carbohydrate) oxidation were estimated using indirect calorimetry. Calcium co-ingestion resulted in a 47% increase in GIP(1-42), a 22% increase in GLP-1 and a 19% increase in insulin areas under the curve for the 120 min following consumption (all P < 0.05). Furthermore, appetite sensations were suppressed by calcium co-ingestion by 12% (P = 0.034). No differences, however, were observed in substrate metabolism (P > 0.05). Ingestion of a high-calcium meal potentiates postprandial GIP(1-42), GLP-1 and insulin concentrations in humans. Subjective appetite is also temporarily suppressed, although substrate metabolism is unaffected.

Glycaemic index of meals affects appetite sensation but not energy balance in active males

Foods with low glycaemic index (LGI) are reported to suppress appetite mainly in overweight population but have not been investigated in athletic adults. The aim of this study was to compare the short-term effects of LGI and high GI (HGI) meals over a day on subsequent subjective appetite sensation, energy intake, energy expenditure, energy balance and resting metabolic rate in physically active males. This cross-sectional randomized crossover study included 14 active males (mean ± SD; age 34.5 ± 8.9 years, body mass index 22.8 ± 2.1 kg m(-2)) to consume LGI and HGI meals on two separate days. On each trial day, participants consumed a breakfast in the laboratory and then left with a packed lunch, dinner and snacks. Appetite scores, energy intake and expenditure were assessed. The area under the curve for appetite scores of the HGI trial was significantly smaller than that of the LGI trial during the laboratory period (p = 0.027) and throughout the day (p = 0.009). No significant differences in energy intake, energy expenditure, energy balance and resting metabolic rate were found between groups, between the trial days and between the corresponding post-trial days. These results show that frequent ingestion of the HGI meals, contrary to the previous reports, suppresses appetite more than that of LGI meals, but did not affect energy balance in physically active normal-weight males.

The effect of milk proteins on appetite regulation and diet-induced thermogenesis

There is increasing evidence to support that a high-protein diet may promote weight loss and prevent weight (re)gain better than a low-protein diet, and that the effect is due to higher diet-induced thermogenesis (DIT) and increased satiety. However, data on the effect of different types of protein are limited. In the present study we compare the effect of whey, casein and milk on DIT and satiety. Seventeen slightly overweight (29 ± 4 kg/m(2)) male subjects completed the study. The study had a randomized, crossover design, where the effect on 4 h postprandial energy expenditure (EE), substrate oxidation and subjective appetite sensation of three isocaloric test meals containing either a whey drink, a casein drink or skim milk was examined. Energy intake (EI) at a subsequent ad libitum lunch was also measured. There was no significant effect on subjective appetite sensation, but EI at lunch was lower after the milk test meal than after the casein (9%; P=0.0260) and the whey (9%; P=0.0258) test meals. Postprandial lipid oxidation was significantly higher after the casein test meal compared with the whey test meal (P=0.0147) when adjusted for baseline values. There was no significant difference in effect on EE, protein oxidation or carbohydrate oxidation. Milk reduced subsequent EI more than isocaloric drinks containing only whey or casein. A small but significant increase in lipid oxidation was seen after casein compared with whey.

Serotonergic Anti-Obesity Agents

The role of serotonin (5-hydroxytryptamine) in appetite control is long established. Serotonergic manipulations reduce food intake in rodents in a manner consistent with satiety. In humans, drugs such as fenfluramine, dexfenfluramine and sibutramine all reduce energy intake, suppress hunger and enhance satiety. Effects on eating behaviour and subjective sensations of appetite are associated with the weight loss-inducing effects of these treatments. Currently, no appetite-suppressing drugs are approved specifically for the treatment of obesity. However, a new generation of serotonergic drugs have progressed through clinical development. The serotonin 5-HT(2C)-receptor selective agonist lorcaserin, a drug specifically developed to target satiety without producing the side effect profiles of its predecessors, has been shown to significantly reduce energy intake and body weight. The weight loss produced by lorcaserin appears modest, and behavioural effects, particularly its supposed satiety-enhancing effects, have yet to be characterized. The monoaminergic re-uptake inhibitor tesofensine has also been shown to produce impressive weight loss in smaller-scale clinical studies. It remains unclear if this drug produces any effects on appetite mediated by serotonin, or whether weight loss is produced largely through enhanced energy expenditure. Evidence indicates that tesofensine strengthens satiety, but behavioural specificity and psychological side effects remain an issue. The serotonergic system remains a viable target for anti-obesity treatment. In this review, we examine the limited behavioural data available on these two new CNS-acting appetite suppressants.

Functionality of alginate based supplements for application in human appetite regulation

The present study investigated the functional properties of different alginate solutions intended as dietary supplements for enhanced satiety and limited energy intake in humans. Characteristics of the three alginates, obtained by NMR spectroscopy, showed differences in their mannuronic:guluronic (M:G) acids ratio. By correlation with their rheological behaviour it was found that alginate solutions with low M:G (M:G=0.8) exhibited stronger gel strength than did solutions with higher M:G (1.3 and 2.5). Subsequently, eight subjects participated in an acute meal test, where two alginate-based preloads with different M:G ratios (0.8 and 2.5) were administered after subjects had fasted overnight. Subjective appetite sensation was assessed over 4h; thereafter an ad libitum meal was served. Self-perceived capacity for food intake decreased (P=0.02), fullness increased (P=0.05), and subsequent energy intake decreased numerically by 10% (P=0.1) after consumption of the alginate formulation with low M:G compared with high M:G. These findings suggest that high-guluronic acid alginates are worth further investigation in relation to appetite regulation.

A Low Glycemic Index Diet Does Not Affect Postprandial Energy Metabolism but Decreases Postprandial Insulinemia and Increases Fullness Ratings in Healthy Women

At present, it is difficult to determine whether glycemic index (GI) is an important tool in the prevention of lifestyle diseases, and long-term studies investigating GI with diets matched in macronutrient composition, fiber content, energy content, and energy density are still scarce. We investigated the effects of 2 high-carbohydrate (55%) diets with low GI (LGI; 79) or high GI (HGI; 103) on postprandial blood profile, subjective appetite sensations, energy expenditure (EE), substrate oxidation rates, and ad libitum energy intake (EI) from a corresponding test meal (LGI or HGI) after consuming the diets ad libitum for 10 wk. Two groups of a total of 29 healthy, overweight women (age: 30.5 ± 6.6 y; BMI: 27.6 ± 1.5 kg/m2) participated in the 10-wk intervention and a subsequent 4-h meal test. The breakfast test meals differed in GI but were equal in total energy, macronutrient composition, fiber content, and energy density. The LGI meal resulted in lower plasma glucose, serum insulin, and plasma glucagon-like peptide (GLP)-1 and higher plasma glucose-dependent insulinotropic polypeptide concentrations than the HGI meal (P = 0.05). Ratings of fullness were slightly higher and the desire to eat something fatty was lower after the test meal in the LGI group (P < 0.05). Postprandial plasma GLP-2, plasma glucagon, serum leptin, plasma ghrelin, EE, substrate oxidation rates, and ad libitum EI at lunch did not differ between groups. In conclusion, postprandial glycemia, insulinemia, and subjective appetite ratings after a test meal were better after 10-wk ad libitum intake of a LGI compared to a HGI diet. EE and substrate oxidation rates were, however, not affected. These findings give some support to recommendations to consume a LGI diet.

Flaxseed dietary fibers suppress postprandial lipemia and appetite sensation in young men

Background and aimDietary fibers (DF) are linked to a reduced risk of life-style diseases, which relate to their physiological effects in the gastrointestinal tract. The aim was to examine whether flaxseed DF-enriched meals suppress postprandial lipemia and reduce appetite. Methods and resultsFour different iso-caloric meals were tested in 18 young men in a double-blind randomized crossover design. Test meals were served after an overnight fast. DF content and source were: control (C): 1.4 g/MJ; whole flaxseed (WF): 2.4 g/MJ from whole flaxseeds; low-mucilage dose (LM): 2.4 g/MJ from flaxseed DF; high-mucilage dose (HM): 3.4 g/MJ from flaxseed DF. During the 7 h test day, subjective appetite sensation was assessed using visual analogue scales and appetite-regulating hormones, and lipemia and glycemia were measured, after which ad libitum energy intake was recorded. There was a significant time × meal effect on triacylglycerols (TG) (p = 0.02) and an 18% smaller area under the curve (AUC) for TG after meal HM compared to meal C was observed (p < 0.01). AUC for insulin was smaller after both LM and HM meals compared to C and WF meals. Higher mean ratings of satiety (p < 0.01) and fullness (p = 0.03) was seen following the HM meal compared to meal C. AUC for ghrelin, CCK and GLP-1 and ad libitum energy intake did not differ between meals, but ghrelin response exhibited a different response pattern after the mucilage-containing meals. ConclusionThese findings suggest that flaxseed DF may suppress postprandial lipemia and appetite although subsequent energy intake was not affected.

Protein choices targeting thermogenesis and metabolism

Dietary proteins stimulate thermogenesis and satiety more than does carbohydrate or fat; however, less is known about the differences between protein sources. The objective was to determine the differential effects of 3 proteins on energy metabolism, satiety, and glucose control. Energy metabolism, satiety, and glucose control were measured in 23 lean, healthy subjects on separate occasions, before and 5.5 h after consumption of 4 isocaloric test meals in a randomized, double-blind, crossover design. Three meals consisting of 50% protein (whey, casein, or soy), 40% carbohydrate, and 10% fat and a fourth meal consisting of 95.5% carbohydrate were compared with a glucose meal that provided the same glucose load as the protein meals. The thermic effect was greater after the whey (14.4 ± 0.5%) than after the casein (12.0 ± 0.6%; P = 0.002) and soy (11.6 ± 0.5%; P = 0.0001) meals and was greater after the whey, casein, and soy meals than after the high-carbohydrate meal (6.6 ± 0.5%; P < 0.0001). Cumulative fat oxidation tended to be greater after the whey meal (16.2 ± 1.1 g) than after the soy meal (13.7 ± 1.0 g; P = 0.097) and was greater after the whey and soy meals than after the high-carbohydrate meal (10.9 ± 0.9 g; P < 0.05). The glycemic response to glucose was attenuated 32% by the proteins (P < 0.001) at the expense of a greater insulin response after whey than after glucose (154%; P = 0.02), casein (143%; P = 0.07), and soy (151%; P = 0.03). Subjective appetite sensations indicated that casein and soy were more satiating than whey (P < 0.01), but whey was more "liked" compared with casein and soy (P = 0.025 and P = 0.09, respectively). The results suggest that different protein sources could be used to modulate metabolism and subsequently energy balance.