NNNS: Effect Appetite/Food Intake (2011)
- Within 10% of their reference body weight, based on 1983 Metropolitan height-weight tables
- Not on any special or restricted diets.
- Outside reference body weight.
- Recruitment: From a population of 800 men and women employed at a New York company, who volunteered.
- Design: Approved by the New York University Committee on Activities Involving Human Subjects. Randomly assigned to one of four groups according to a counterbalanced design.
- Blinding used: Subjects could see the difference between the water and the three types of sweetened drinks. The types of sweeteners used in the drinks were not revealed to either the investigators or the subjects
- Intervention: Consumed a standard breakfast followed, three hours later, by 200ml of either water or a sweetened drink. One hour later, subjects' ad libitum consumption of a standarized lunch was measured. Subjects recorded self-assessments of hunger-related indices every half-hour on visual analogue scales.
- Statistical Analysis: Repeated measures of ANOVA, Scheffe post hoc pairwise comparisons by SAS program, 0.05 statistical effect, statistical power of 0.87.
- Visual analogue scales(VAS): Developed for measuring desire to eat, hunger, fullness, prospective consumption, pleasantness of food or drink and degree of stomach rumbling. Scales validated and sensitive to nutritional manipulations.
- Short questionnaire: Concerning eating habits, including usual time of meals, foods usually consumed for breakfast and midmorning snacks, preference for sweet foods and sweet drinks and anticipated date of their next menstual period. Instructed not to consume any food after 10:00 p.m. the night before each day of the study.
- Day One of study: Questionnaire and VAS for each time period of the study (every half-hour from 8:00 a.m. to 2:00 p.m. for all four days.
- Study days: Four study days were non-consecutive for two weeks. Breakfast was 400kcal, consiting of 30g unsweetened cereal, 120ml 2% fat milk, 40g strawberries and 180ml orange juice. Afterwards rated preference for breakfast on the VAS form.
- At 11:15 a.m., subjects consumed (in less than 30 seconds) 200ml of a drink consisting of either water or a red cherry-flavored drink sweetened with either aspartme, sucrose or saccharin. Drinks were sweetened according to standard sweetness equivalence: Aspartame, 180 x sucrose; saccharin 300 x sucrose. The 200ml drinks provided 20g sucrose, 112mg aspartame or 67.5mg saccharin. These sweetener levels are similar to those typically available to consumers. At 12:15 p.m., a group lunch was served, consisting of pasta salad with chicken, green peas, tomatoes, red peppers and spices (320kcal/200g serving) and water ad libitum. The same lunch was served all four days. Subjects were provided with 200g of salad to start with and were allowed additional servings, which were weighed.
- Initial N: 20 subjects (18 women and two men)
- Attrition: Not all subjects completed all four days of the study. No number reported for drop-out.
- Age: 23 to 37 years, 29±1 year
- Ethnicity: Not specified
- Anthropometrics: 61.7±1.5kg
- Location: New York University.
Significant effect (P<0.05) of drink type on VAS scores 15 and 45 minutes after drinks were consumed, but not for other times or for lunch consumption.
Hunger related ratings after drink consumption were generally highest for water, lower for non-caloric sweeteners and lowest for sugar. Pairwise comparisons of mean ratings significantly affected by drink type showed only limited significant differences between individual means of these dependent variables. Mean ratings of desire to eat 45 minutes after the water pre-load was significantly higher than was the mean rating after the sugar pre-load (7.9 vs. 4.7, respectively; P<0.05). Subjects liked water significantly better than the saccharin-sweetened drink (5.5 vs. 1.5, respectively; P<0.05).
Hunger Related Index
- Under many circumstances, non-caloric sweeteners do not increase hunger levels or food consumption.
- The results found in some other studies may be due to different experimental conditions. Precise application and manipulation of independent variables is essential in future investigations. Useful to examine in the future: Size and type of pre-load vehicle, pre-load post-ingestive effects, subjects' dietary state before the test, intensity and quantity of pre-load sweetener, timing of pre-load and subsequent meal consumption, composition of the meal offered after the pre-load, type of subjects (obese, those with greater sweet tooth who habitually eat greater amounts of sweet foods, etc.).
- Dependent variable measure: Psychological and physiological variables. Long-term studies are needed to examine the larger question of whether incorporating NCS foods and beverages into the diet can favorably affect food intake, weight loss and weight maintence. Differences in comparison to other studies may be due to the fact that this was a short-term study, amounts of sweeteners in pre-loads and variation in subjects' dietary states at the beginning of the test period.
|University/Hospital:||New York University|
Quality Criteria Checklist: Primary Research
|1.||Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies)||Yes|
|2.||Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about?||Yes|
|3.||Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice?||Yes|
|4.||Is the intervention or procedure feasible? (NA for some epidemiological studies)||Yes|
|1.||Was the research question clearly stated?||Yes|
|1.1.||Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified?||Yes|
|1.2.||Was (were) the outcome(s) [dependent variable(s)] clearly indicated?||Yes|
|1.3.||Were the target population and setting specified?||Yes|
|2.||Was the selection of study subjects/patients free from bias?||No|
|2.1.||Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study?||No|
|2.2.||Were criteria applied equally to all study groups?||Yes|
|2.3.||Were health, demographics, and other characteristics of subjects described?||No|
|2.4.||Were the subjects/patients a representative sample of the relevant population?||Yes|
|3.||Were study groups comparable?||Yes|
|3.1.||Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)||Yes|
|3.2.||Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?||Yes|
|3.3.||Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.)||Yes|
|3.4.||If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis?||N/A|
|3.5.||If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.)||N/A|
|3.6.||If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")?||N/A|
|4.||Was method of handling withdrawals described?||No|
|4.1.||Were follow-up methods described and the same for all groups?||Yes|
|4.2.||Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.)||No|
|4.3.||Were all enrolled subjects/patients (in the original sample) accounted for?||No|
|4.4.||Were reasons for withdrawals similar across groups?||No|
|4.5.||If diagnostic test, was decision to perform reference test not dependent on results of test under study?||N/A|
|5.||Was blinding used to prevent introduction of bias?||Yes|
|5.1.||In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate?||Yes|
|5.2.||Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.)||Yes|
|5.3.||In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded?||N/A|
|5.4.||In case control study, was case definition explicit and case ascertainment not influenced by exposure status?||N/A|
|5.5.||In diagnostic study, were test results blinded to patient history and other test results?||N/A|
|6.||Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described?||Yes|
|6.1.||In RCT or other intervention trial, were protocols described for all regimens studied?||Yes|
|6.2.||In observational study, were interventions, study settings, and clinicians/provider described?||N/A|
|6.3.||Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?||Yes|
|6.4.||Was the amount of exposure and, if relevant, subject/patient compliance measured?||No|
|6.5.||Were co-interventions (e.g., ancillary treatments, other therapies) described?||No|
|6.6.||Were extra or unplanned treatments described?||N/A|
|6.7.||Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups?||Yes|
|6.8.||In diagnostic study, were details of test administration and replication sufficient?||N/A|
|7.||Were outcomes clearly defined and the measurements valid and reliable?||No|
|7.1.||Were primary and secondary endpoints described and relevant to the question?||Yes|
|7.2.||Were nutrition measures appropriate to question and outcomes of concern?||Yes|
|7.3.||Was the period of follow-up long enough for important outcome(s) to occur?||Yes|
|7.4.||Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures?||No|
|7.5.||Was the measurement of effect at an appropriate level of precision?||No|
|7.6.||Were other factors accounted for (measured) that could affect outcomes?||No|
|7.7.||Were the measurements conducted consistently across groups?||No|
|8.||Was the statistical analysis appropriate for the study design and type of outcome indicators?||No|
|8.1.||Were statistical analyses adequately described and the results reported appropriately?||No|
|8.2.||Were correct statistical tests used and assumptions of test not violated?||No|
|8.3.||Were statistics reported with levels of significance and/or confidence intervals?||Yes|
|8.4.||Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)?||No|
|8.5.||Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?||No|
|8.6.||Was clinical significance as well as statistical significance reported?||Yes|
|8.7.||If negative findings, was a power calculation reported to address type 2 error?||N/A|
|9.||Are conclusions supported by results with biases and limitations taken into consideration?||Yes|
|9.1.||Is there a discussion of findings?||Yes|
|9.2.||Are biases and study limitations identified and discussed?||Yes|
|10.||Is bias due to study's funding or sponsorship unlikely?||Yes|
|10.1.||Were sources of funding and investigators' affiliations described?||Yes|
|10.2.||Was the study free from apparent conflict of interest?||Yes|