EAL

NNNS: Energy Density (2006)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To monitor changes in ad libitum energy and macronutrient intakes, body weight and body composition during 10 weeks of supplementation with either sucrose or artificial sweeteners.

Inclusion Criteria:

20 to 50 years of age
Overweight (BMI of 25 to 30 or greater than 10% overweight, according to weight-height tables)
Healthy
Not dieting
Not pregnant or lactating.

Exclusion Criteria:

Pregnant or lactating
Dieting, not healthy.

Description of Study Protocol:

Recruitment

Posters and advertisements in newspapers and magazines. Approved by Municipal Ethical Committee of Copenhagen and Fredericksberg. Subjects gave written consent after the experimental procedure had been explained to them orally and in writing. Received about 300 calls from interested subjects and provided oral and written communication to 100.

Design

Subjects randomly assigned to the two intervention groups (sucrose group or sweetener group), which were matched for sex, weight, height, BMI, fat mass, fat-free mass and ususual amount of physical activity.

Blinding Used

Subjects were not informed about the true purpose of the study, but were told that they would recieve supplements containing artificial sweeteners, some of which would be newly developed.

Intervention

Consumption of either sucrose or artificial sweeteners.

Statistical Analysis

All result were shown with means and SEM. Initial group differences were tested by using unpaired T-tests. Other differences between groups and times were tested by using parametric analysis of variance with the general linear model procedure in SAS. Factors were diet, time and diet x time with subject group as an error term for group effects. When interaction of diet and time were significant, Turkey's post hoc tests were applied.
Linear and stepwise regression analyses were performed. Significance at P<0.05.
Statgraphics software version 4.2 and SAS version 6.12 were used. ANOVA.

Data Collection Summary:

Timing of Measurements

A two-week pilot study on four people was performed before the intervention to test the supplements, evaluate comprehensibility of the different questionnaires and to practice the measurement procedures.
Several measurements were performed before, during and at the end of the 10-week intervention period.
At Weeks Zero, Two, Four, Six, Eight and 10, body weight, fat mass and fat-free mass were measured.
At Weeks Zero, Five and 10, subjects completed seven-day dietary records, seven-day diaries (for monitoring hunger, fullness, palatability of the food and well-being), 24-hour urine collections and diurnal appetitie scores.
At Weeks Zero and 10, dual energy X-ray absorptiometry (DXA) scans were performed and waist-to-hip ratio, sagittal height (height of abdomen when lying in a supine position) and blood pressure were measured.
Subjects completed a three-factor questionnaire about eating behavior and a questionnaire about habitual physical activity.
After intervention: Subjects completed a questionnaire about the experimental diet.
Once weekly, throughout the intervention, subjects came to the research deparatment to collect their drinks and foods and to deliver their diaries, questionnaires, urine samples and other materials.

Variables

Experimental Diets: Subjects were instructed to consume a specific minimum amount of either sucrose-sweetened or artificially sweetened drinks and foods every day during the 10-week intervention period. A minimum amount was prescribed to ensure subjects would consume at least this amount. For the sucrose group, about 70% of the sucrose came from drinks and about 30% from solid foods. About 80% by weight of the supplements were beverages and about 20% by weight were solid foods. This distribution corresponds to the population's intake of artificially sweetened foods. The beverages consisted of soft drinks and flavored fruit juices. Caps on all drinks were changed and labels removed for the study. To keep the fat intake similar, subjects in the sweetener group were given additional butter or corn oil every week.
Anthropometry: DXA scans
Urine Samples: Collected 24-hour urine samples during the sixth day and night of every dietary record (Weeks Zero, Five and 10) to validate dietary records.
Questionnaires: Seven-day diaries, appetite sensations (hunger, satiety, prospective consumption, fullness and desire to eat something sweet, salty, fat rich or savory) registered under free-living conditions by a visual analogue scale and a three-factor eating questionnaire.

Description of Actual Data Sample:

Initial N: 42 subjects enrolled in the study.
Attrition: 41 of them (35 women and six men; N=21 from the sucrose group and N=20 from the sweetener group) completed the study.
Age: Sucrose group 33.3±2.0; sweetener group 37.1±2.2
Ethnicity: Unknown (study outside US)
Other relevant demographics: Study approved by the Municipal Ethical Committee of Copenhagen and Frederiksberg, being in accordance with the Helinski II Delaration.

Anthropometrics

There were no significant differences between the groups (unpaired T-test).

Location

Research Department of Human Nutrition, Center for Advanced Food Studies, The Royal Veterinary and Agricultural University, Frederiksberg, Denmark.

Summary of Results:

Changes in Anthropometric Data, Blood Pressure and Physical Activity in the Sucrose and Sweetener Groups After 10 Weeks of Supplementation¹

	Sucrose Group (N=21)	Sweetener Group (N=20)	Difference Between Groups²
Body Weight (kg)	1.6±0.4³	-1.0±0.4⁴	2.6 (1.3, 3.8)
Body Weight (percentage)	1.8±0.5	-1.4±0.6⁴	3.2 (1.7, 4.8)
Fat Mass (kg)	1.3±0.5	-0.3±0.4⁵	1.6 (0.4, 2.8)
Fat-Free Mass (kg)	0.3±0.3	-0.7±0.2⁶	1.0 (0.1, 1.8)
BMI (kg/m²)	0.5±0.2	-0.4±0.2⁴	0.9 (0.5, 1.4)
Waist-to-Hip Ratio	0.00±0.01	0.01±0.00	0.00 (-0.01, 0.02)
Sagittal Height (cm)	0.2±0.1	-0.1±0.2	0.34 (-0.13, 0.81)
Systolic BP (mm Hg)	3.8±2.0	-3.1±1.3⁵	6.9 (2.0, 11.9)
Diastolic BP (mm Hg)	4.1±1.7	-1.2±1.3⁶	5.3 (1.1, 9.6)
Physical Activity (hours per week)	-0.4±1.8	0.1±2.1	-0.5 (-6.1, 5.1)
Physical Activity Level⁷	0.1±0.2	0.4±0.3	-0.3 (-1.0, 0.5)

1=Blood pressure
2=Mean difference (sucrose group - sweetener group) with 95% CI in parentheses.
3=±SEM.
4-6=Significantly different from sucrose group (unpaired T-test)

4=P<0.001
5=P<0.01
6=P<0.05.

7=Rated from one to five; 1=low, 5=high.

Other Findings

Table One: No significant changes in sagittal height, physical activity or activity level; with a three-factor eating questionnaire.
Table Two: Energy intake from the sucrose supplements was about three times higher than that from the sweetener supplements (diet effect, P<0.001). Significantly higher amounts of total carbohydrates and sucrose (grams and percentage of energy) were consumed from sucrose supplements, whereas significantly higher amounts of fat and protein (percentage of energy) were provided in the sweetener supplements. Intakes of fat and protein in absolute amounts and the total weight of foods and drinks did not differ significanly between the two groups. Average intake of sweetened drinks was about 1,285g per day. This was determined by multiplying the total average weight of foods and drinks consumed (1,600g per day) by the percentage of the total weight that was contributed by drinks (80%).
Figure One, Table Three: Records of ad libitum food intake (including supplements) showed that total energy intake increased significantly in the sucrose group (by 1.5MJ per day), but remained constant in the sweetener group, compared with habitual energy intake (Week Zero). The average difference between the two groups was 2.6MJ per day during the intervention and 185MJ for the entire 70-day period. The energy density of the diet was significantly lower in the sweetener group from Week Zero to Week Five. Total carbohydrate intake in grams increased significantly in the sucrose group, mainly because of the sucrose intake, but did not change significantly in the sweetener group.
Carbohydrate intake as a percentage of energy increased significantly in the sucrose group (from 49% before the intervention to 58% during the intervention), but remained constant in the sweetener group (45% before and 44% during the intervention); diet x time interaction P<0.001.
Intakes of fat and protein (g) did not differ significantly between the groups, but the percentage of energy from fat decreased significantly in the sucrose group (from 33% to 28%) and remained unchanged in the sweetener group (34%) diet x time interaction P=0.005.

Author Conclusion:

Overweight subjects who consumed fairly large amounts of sucrose (28% of energy), mostly as beverages, had increased energy intake, body weight, fat mass and blood pressure after 10 weeks. These effects were not observed in a similar group of subjects who consumed artificial sweeteners.
One of the most likely reason for these differences between the groups was the use of large amounts of beverages, giving rise to overconsumption of energy on the high-sucrose diet. Therefore, overweight individuals may want to consider choosing beverages containing artificial sweeteners, rather than sucrose, to prevent weight gain.

Funding Source:

Industry:

Danisco Sugar

Food Company:

Not-for-profit

Foundation associated with industry:

Reviewer Comments:

Good long-term weight program
Products: Drinks and solid foods (yogurt, marmalade, ice cream, stewed fruits).

Quality Criteria Checklist: Primary Research
Relevance Questions
	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

Validity Questions
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?		Yes
	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?	Yes
	2.2.	Were criteria applied equally to all study groups?	Yes
	2.3.	Were health, demographics, and other characteristics of subjects described?	Yes
	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?	Yes
	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?	Yes
	6.5.	Were co-interventions (e.g., ancillary treatments, other therapies) described?	N/A
	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?	N/A
	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?		Yes
	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?	Yes
	7.5.	Was the measurement of effect at an appropriate level of precision?	Yes
	7.6.	Were other factors accounted for (measured) that could affect outcomes?	Yes
	7.7.	Were the measurements conducted consistently across groups?	Yes
8.	Was the statistical analysis appropriate for the study design and type of outcome indicators?		Yes
	8.1.	Were statistical analyses adequately described and the results reported appropriately?	Yes
	8.2.	Were correct statistical tests used and assumptions of test not violated?	Yes
	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)?	Yes
	8.5.	Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)?	Yes
	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