Anne Raben

Reproducibility, power and validity of visual analogue scales in assessment of appetite sensations in single test meal studies

OBJECTIVE: To examine reproducibility and validity of visual analogue scales (VAS) for measurement of appetite sensations, with and without a diet standardization prior to the test days.DESIGN: On two different test days the subjects recorded their appetite sensations before breakfast and every 30 min during the 4.5 h postprandial period under exactly the same conditions.SUBJECTS: 55 healthy men (age 25.6±0.6 y, BMI 22.6±0.3 kg/m2).MEASUREMENTS: VAS were used to record hunger, satiety, fullness, prospective food consumption, desire to eat something fatty, salty, sweet or savoury, and palatability of the meals. Subsequently an ad libitum lunch was served and energy intake was recorded. Reproducibility was assessed by the coefficient of repeatability (CR) of fasting, mean 4.5 h and peak/nadir values.RESULTS: CRs (range 20–61 mm) were larger for fasting and peak/nadir values compared with mean 4.5 h values. No parameter seemed to be improved by diet standardization. Using a paired design and a study power of 0.8, a difference of 10 mm on fasting and 5 mm on mean 4.5 h ratings can be detected with 18 subjects. When using desires to eat specific types of food or an unpaired design, more subjects are needed due to considerable variation. The best correlations of validity were found between 4.5 h mean VAS of the appetite parameters and subsequent energy intake (r=±0.50−0.53, P<0.001).CONCLUSION: VAS scores are reliable for appetite research and do not seem to be influenced by prior diet standardization. However, consideration should be given to the specific parameters being measured, their sensitivity and study power.

GLUCAGON-LIKE PEPTIDE 1 PROMOTES SATIETY AND SUPPRESSES ENERGY INTAKE IN HUMANS

We examined the effect of intravenously infused glucagon-like peptide 1 (GLP-1) on subjective appetite sensations after an energy-fixed breakfast, and on spontaneous energy intake at an ad libitum lunch. 20 young, healthy, normal-weight men participated in a placebo-controlled, randomized, blinded, crossover study. Infusion (GLP-1, 50 pmol/ kg.h or saline) was started simultaneously with initiation of the test meals. Visual analogue scales were used to assess appetite sensations throughout the experiment and the palatability of the test meals. Blood was sampled throughout the day for analysis of plasma hormone and substrate levels. After the energy-fixed breakfast, GLP-1 infusion enhanced satiety and fullness compared with placebo (treatment effect: P < 0.03). Furthermore, spontaneous energy intake at the ad libitum lunch was reduced by 12% by GLP-1 infusion compared with saline (P = 0.002). Plasma GLP-1, insulin, glucagon, and blood glucose profiles were affected significantly by the treatment (P < 0.002). In conclusion, the results show that GLP-1 enhanced satiety and reduced energy intake and thus may play a physiological regulatory role in controlling appetite and energy intake in humans.

Effect of sensory perception of foods on appetite and food intake: a review of studies on humans

Objective: How much do the sensory properties of food influence the way people select their food and how much they eat? The objective of this paper is to review results from studies investigating the link between the sensory perception of food and human appetite regulation.Content of the review: The influence of palatability on appetite and food intake in humans has been investigated in several studies. All reviewed studies have shown increased intake as palatability increased, whereas assessments of the effect of palatability using measures of subjective appetite sensations have shown diverging results, for example, subjects either feel more hungry and less full after a palatable meal compared to a less palatable meal, or they feel the opposite, or there is no difference. Whether palatability has an effect on appetite in the period following consumption of a test meal is unclear.Several studies have investigated which sensory properties of food are involved in sensory-specific satiety. Taste, smell, texture and appearance-specific satieties have been identified, whereas studies on the role of macronutrients and the energy content of the food in sensory-specific satiety have given equivocal results. Different studies have shown that macronutrients and energy content play a role in sensory-specific satiety or that macronutrients and energy content are not a factor in sensory-specific satiety. Sensory-specific satiety may have an important influence on the amount of food eaten. Studies have shown that increasing the food variety can increase food and energy intake and in the short to medium term alter energy balance. Further knowledge about the importance of flavour in appetite regulation is needed, for example, which flavour combinations improve satiety most, the possible connection between flavour intensity and satiety, the effect of persistence of chemesthetic sensation on palatability and satiety, and to what extent genetic variation in taste sensitivity and perception influences dietary habits and weight control.

The effect of physiological levels of glucagon-like peptide-1 on appetite, gastric emptying, energy and substrate metabolism in obesity.

OBJECTIVE: Peripheral infusions of glucagon-like peptide-1 (GLP-1) in humans have been shown to inhibit gastrointestinal motility and decrease hunger and energy intake. However, these investigations used supraphysiological doses. The objective of this study was to investigate the effects of a GLP-1 infusion in a physiological dose on appetite sensations, energy intake, gastric emptying, energy and substrate metabolism.METHODS: Eighteen obese men participated in the placebo-controlled, randomized, single-blinded, cross-over study with infusion of GLP-1 or saline. Resting metabolic rate (RMR) and substrate oxidations were measured by ventilated hood before and after an energy-fixed breakfast. Gastric emptying was measured using paracetamol as a marker. Visual analogue scales were used to assess appetite sensations, thirst and comfort throughout the experiment and palatability of the test meals. Blood was sampled for analysis of hormones (GLP-1, GLP-2, glucose-dependent insulinotropic polypeptide (GIP), insulin, glucagon), and substrates (glucose, lactate, non-esterified fatty acids (NEFA), triacylglycerol (TAG)). Ad libitum energy intake at lunch was registered.RESULTS: Following the breakfast, GLP-1 infusion suppressed ratings of hunger and prospective food consumption (P<0.05), whereas all other subjective ratings and ad libitum energy intake were unaffected. RMR, carbohydrate oxidation and gastric emptying rate were lower during the GLP-1 infusion compared with the saline infusion (P<0.001, P<0.05, P<0.0001, respectively). All plasma hormone and substrate profiles, except NEFA, were significantly reduced by GLP-1 (P<0.0001).CONCLUSION: It is concluded that GLP-1 in physiological concentrations powerfully reduces the rate of entry of nutrients into the circulation by a reduction of gastric emptying rate in obese subjects. The effect of GLP-1 on appetite and food intake may be beneficial in weight reduction.

Maternal Glycemic Control and Hypoglycemia in Type 1 Diabetic Pregnancy: A randomized trial of insulin aspart versus human insulin in 322 pregnant women

OBJECTIVE—To assess the safety and efficacy of insulin aspart (IAsp) versus regular human insulin (HI) in basal-bolus therapy with NPH insulin in pregnant women with type 1 diabetes. RESEARCH DESIGN AND METHODS—Subjects (n = 322) who were pregnant or planning pregnancy were randomized to IAsp or HI as meal-time insulin in an open-label, parallel-group, multicenter study. Subjects had A1C ≤8% at confirmation of pregnancy. Insulin doses were titrated toward predefined glucose targets and A1C <6.5%. Outcomes assessed included risk of major maternal hypoglycemia, A1C, plasma glucose profiles, and maternal safety outcomes. RESULTS—Major hypoglycemia occurred at a rate of 1.4 vs. 2.1 episodes/year exposure with IAsp and HI, respectively (relative risk 0.720 [95% CI 0.36–1.46]). Risk of major/major nocturnal hypoglycemia was 52% (RR 0.48 [0.20–1.143]; P = NS) lower with IAsp compared with HI. A1C was comparable with human insulin in second (IAsp-HI −0.04 [−0.18 to 0.11]) and third (−0.08 [−0.23 to 0.06]) trimesters. A total of 80% of subjects achieved an A1C ≤6.5%. At the end of first and third trimesters, average postprandial plasma glucose increments were significantly lower with IAsp than HI (P = 0.003 and P = 0.044, respectively), as were mean plasma glucose levels 90 min after breakfast (P = 0.044 and P = 0.001, respectively). Maternal safety profiles and pregnancy outcomes were similar between treatments. CONCLUSIONS—IAsp is at least as safe and effective as HI when used in basal-bolus therapy with NPH insulin in pregnant women with type 1 diabetes and may potentially offer some benefits in terms of postprandial glucose control and preventing severe hypoglycemia.

The use of glycaemic index tables to predict glycaemic index of composite breakfast meals

The applicability of the glycaemic index (GI) in the context of mixed meals and diets is still debatable. The objective of the present study was to investigate the predictability of measured GI in composite breakfast meals when calculated from table values, and to develop prediction equations using meal components. Furthermore, we aimed to study the relationship between GI and insulinaemic index (II). The study was a randomised cross-over meal test including twenty-eight healthy young men. Thirteen breakfast meals and a reference meal were tested. All meals contained 50 g available carbohydrate, but differed considerably in energy and macronutrient composition. Venous blood was sampled for 2 h and analysed for glucose and insulin. Prediction equations were made by regression analysis. No association was found between predicted and measured GI. The meal content of energy and fat was inversely associated with GI (R(2) 0.93 and 0.88, respectively; P<0.001). Carbohydrate content (expressed as percentage of energy) was positively related to GI (R(2) 0.80; P<0.001). Using multivariate analysis the GI of meals was best predicted by fat and protein contents (R(2) 0.93; P<0.001). There was no association between GI and II. In conclusion, the present results show that the GI of mixed meals calculated by table values does not predict the measured GI and furthermore that carbohydrates do not play the most important role for GI in mixed breakfast meals. Our prediction models show that the GI of mixed meals is more strongly correlated either with fat and protein content, or with energy content, than with carbohydrate content alone. Furthermore, GI was not correlated with II.

Effect of sucrose on inflammatory markers in overweight humans

BACKGROUND Observational studies have found that dietary glycemic load is positively associated with C-reactive protein (CRP) concentrations in healthy humans, which suggests that the type of carbohydrate ingested influences inflammatory activity. OBJECTIVE We investigated the effect of a diet with a high content of sucrose or artificial sweeteners on the inflammatory markers CRP, haptoglobin, and transferrin in overweight subjects. DESIGN Overweight men and women consumed daily food and drink supplements containing either sucrose [n = 21; body mass index (BMI, in kg/m2): 28.0] or artificial sweeteners (n = 20; BMI: 27.6), predominantly from soft drinks (70%; average approximately 1.3 L/d) for 10 wk. RESULTS During the intervention, sucrose intake increased by 151% in the sucrose group and decreased by 42% in the sweetener group, resulting in a 1.6-kg weight gain in the sucrose group and a 1.2-kg weight loss in the sweetener group over 10 wk (P < 0.001). Concentrations of haptoglobin, transferrin, and CRP increased by 13%, 5%, and 6%, respectively, in the sucrose group and decreased by 16%, 2%, and 26%, respectively, in the sweetener group (between-group differences: P = 0.006, P = 0.01, and P = 0.1, respectively). Adjustment for changes in body weight and energy intake did not substantially influence this outcome. CONCLUSIONS The study shows that in the present group of overweight subjects a high consumption of sugar-sweetened foods and drinks increased haptoglobin and transferrin but had, at best, only a limited influence on CRP.

Overweight men's motivations and perceived barriers towards weight loss.

Objective:To explore motivation and perceived barriers towards weight loss among Danish men.Design:The study was of an explorative nature, using qualitative focus group interviews as a method.Setting:Copenhagen, Denmark.Subjects:Twenty-two overweight men, at the age of 25–44 years and motivated for weight loss, were recruited and distributed into four focus groups. The men were primarily unskilled workers. Overall 13 men participated and each group contained three or four participants.Intervention:The interview guide was partly structured, partly unstructured and the themes of the interviews were motives and perceived barriers towards weight loss.Results:Main barriers for losing weight appeared to be lack of motivation and the perception of the slimming diet. The men had a desire to have a lean appearance and avoid illness, but in all the interviews it appeared that the strongest motive for losing weight was a strong desire to become more effective and a greater asset for ones workplace. Overweight subjects were considered less effective and attractive for the labour market.Conclusion:This study indicates that if men from lower socioeconomic backgrounds are to be motivated to weight loss the focus should not be on leanness and good health but rather on increased effectiveness and performance, and the arena should include the working place.Sponsorship:The Royal Veterinary and Agricultural University supplied the necessary equipment and conference rooms.

Replacement of dietary fat by sucrose or starch: Effects on 14 d ad libitum energy intake, energy expenditure and body weight in formerly obese and never-obese subjects

OBJECTIVE: To investigate the impact of a high-sucrose diet vs a high-starch and a high-fat diet on 14 d ad libitum energy intake, body weight, energy expenditure and sympathoadrenal activity. MEASURMENTS: Food intake; body weight and composition (bioelectrical impedance); 24 h energy expenditure, substrate oxidation rates, spontaneous physical activity, heart rate and appetite sensations in a respiration chamber (VAS scores); plasma catecholamine concentration and blood pressure. SUBJECTS: Twenty normal-weight, healthy women, 9 post-obese (body mass index (BMI): 22.9±0.7 kg/m2) and 11 closely matched controls (BMI: 22.6±0.4 kg/m2). RESULTS: Average 14 d ad libitum energy intake was 13% and 12% lower on the starch diet compared with the sucrose and fat diets, respectively (P<0.05). In both post-obese and normal-weight subjects, body weight and fat mass decreased significantly on the starch diet (by 0.7±0.2 kg and 0.4±0.1 kg, respectively, P<0.05). No changes were observed on the fat or sucrose diets. After 14 d on the sucrose diet, 24 h energy expenditure as well as postprandial plasma adrenaline and noradrenaline concentrations, were significantly increased compared with the other two diets. Overall satiety and palatability ratings were also highest on the sucrose diet. CONCLUSION: Intake of a 14-d ad libitum high-starch diet decreased energy intake and body weight compared with a high-fat or high-sucrose diet. The increased energy expenditure observed on the sucrose-rich diet can probably be explained both by the increased intake of energy and fructose (mainly from sucrose) on this diet.

The effect of glucagon-like peptide-1 on energy expenditure and substrate metabolism in humans

OBJECTIVE: To investigate the effects of a near-physiological peripheral glucagon-like peptide-1 (GLP-1) infusion, during and after a breakfast of fixed energy content, on resting energy expenditure, substrate oxidation and metabolism and the desire to eat specific types of food in humans.DESIGN: A placebo-controlled, randomized, blinded, cross-over study. Infusion (GLP-1, 50 pmol/kg×h or saline) was started simultaneously with initiation of the test meals.SUBJECTS: 20 healthy, normal weight (body mass index 20.3–25.7 kg/m2) men of 20–31 y of age.MEASUREMENTS: Energy expenditure and substrate oxidations were measured before and for 4 h after standard breakfast (20% of calculated daily energy requirements, 50% of energy from carbohydrates, 37% of energy from fat and 13% of energy from protein) using a ventilated hood system. Visual analogue scales were used throughout the experiment to assess the desire to eat specific types of food and the palatability of the test meals. Blood was sampled throughout the day for analysis of plasma hormone and substrate concentrations.RESULTS: Diet-induced thermogenesis (DIT) was lower (47%) on the GLP-1 infusion than on the saline infusion (P<0.0001). This was due to a lower carbohydrate oxidation (P<0.01). No differences in fat oxidation or total 4 h protein oxidation were observed. All hormone and substrate profiles except non-esterified fatty acids (NEFA) and cholecystokinin (CCK) were significantly suppressed (GLP-2 completely suppressed) during the GLP-1 infusion, whereas profiles of NEFA and CCK differed in time course during the two treatments (treatment × time effect), P<0.0001). GLP-1 infusion also suppressed the desire to eat all food types following the breakfast (treatment effect: P<0.05).CONCLUSION: Peripheral GLP-1 decreased DIT and carbohydrate oxidation, probably secondary to a delayed absorption of nutrients, since substrate and hormone concentrations in plasma were suppressed during GLP-1 infusion. Endogenous secretion of GLP-1 and GLP-2 was completely suppressed by GLP-1 infusion. Finally, the desire to eat any type of food was decreased by exogenous administrated GLP-1.