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Effect of Polyphenol-rich Dark Chocolate on Body Weight in Overweight and Obese Adults

This study has been completed.
Barry Callebaut
Information provided by (Responsible Party):
Grace Farhat, Queen Margaret University Identifier:
First received: December 10, 2012
Last updated: October 20, 2014
Last verified: May 2013
The aim of this study is to investigate if dark chocolate rich in polyphenols decreases body weight/ body fat in the overweight and obese adult population.

Condition Intervention
Body Weight
Other: Polyphenol-rich Dark chocolate
Other: Placebo Dark chocolate

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single Blind (Participant)
Primary Purpose: Basic Science
Official Title: Effect of Polyphenol-rich Dark Chocolate on Body Weight in Overweight and Obese Adults: A Pilot Study

Resource links provided by NLM:

Further study details as provided by Queen Margaret University:

Primary Outcome Measures:
  • Change in Body weight [ Time Frame: Baseline, week 6, week 12 and week 16 ]
    The body weight will be measured using a digital scale

Secondary Outcome Measures:
  • Change in Body Fat percentage [ Time Frame: Baseline, week 6, week 12 and week 16 ]
  • Change in Waist circumference [ Time Frame: Baseline, week 6, week 12 and week 16 ]
  • Change in urinary Cortisol-to-cortisone ratio [ Time Frame: Baseline, week 6 and week 12 ]

Enrollment: 14
Study Start Date: January 2013
Study Completion Date: January 2014
Primary Completion Date: July 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Polyphenol-rich Dark chocolate
Dark chocolate with 500 mg of polyphenols
Other: Polyphenol-rich Dark chocolate
Participants will be asked to consume 20g of dark chocolate containing 500mg of polyphenols daily for a period of 12 weeks
Placebo Comparator: Placebo Dark chocolate
This chocolate contains little or no polyphenols
Other: Placebo Dark chocolate
Participants will be asked to consume 20g of dark chocolate containing little or no polyphenols for a period of 12 weeks

Detailed Description:
Polyphenols are phytochemicals widely available in plants, and may have several favourable effects on health. Dark chocolate (DC) is one of the highest sources of polyphenols in foods. Animal and in vitro studies have demonstrated that cocoa and dark chocolate may exert anti-obesity effects mainly due to the polyphenol effect on glucose and fatty acid metabolism. Human studies have showed that regular chocolate eaters have a lower body weight compared to non regular eaters, and that DC promotes satiety and reduces cravings. The aim of this pilot study is to investigate the effect of polyphenol-rich DC on body weight in the overweight and obese adult population, when incorporated into a non-restricted diet. Twenty-eight apparently healthy volunteers will be recruited. Participants will randomly receive 20g daily of one of the two different types of DC: Placebo DC (low in polyphenols) or DC rich in polyphenols (500mg) for a period of twelve weeks. Participants will be asked to make three appointments and one follow-up appointment to the university clinical lab. Anthropometric measurements (height, weight, waist circumference, body fat percentage) will be taken during each visit. Compliance will be defined by the intake of 85 % or more of the chocolate weekly, and will be tested by the measure of total polyphenols in a 24-hour urine sample before, during and at the end of the intervention. To monitor any fluctuations in the participants' diet or physical activity during the study period, a three-day diet diary, a Food Frequency questionnaire assessment for polyphenol intake and a physical activity questionnaire will be collected before the start of the study and every four weeks. A follow-up appointment (four weeks after the end of intervention) will check if any differences in anthropometric measures have been maintained. Data will be analysed with an ANCOVA with time (pre- and post-) and treatment (DC and placebo) as between-subject factor. This study will have novel findings and will be the basis for a future larger trial.

Ages Eligible for Study:   18 Years to 65 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Healthy adults
  • BMI between 25-35
  • Males and Females
  • Age: 18-65 years

Exclusion Criteria:

  • Participants with cardiovascular diseases, hypertension or diabetes
  • Participants taking any medications that affect insulin, cholesterol, triglycerides or Blood pressure
  • Participants who recently participated or are currently on a weight management program
  • Participants with regular consumption of cocoa or DC (> 1 serving/week)
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01749852

United Kingdom
Queen Margaret University Lab
Musselburgh, East Lothian, United Kingdom, EH21 6UU
Sponsors and Collaborators
Queen Margaret University
Barry Callebaut
Study Director: Emad Al-Dujaili, PhD Queen Margaret University
  More Information

Responsible Party: Grace Farhat, PhD research student, Queen Margaret University Identifier: NCT01749852     History of Changes
Other Study ID Numbers: DC-BW 01
Study First Received: December 10, 2012
Last Updated: October 20, 2014

Additional relevant MeSH terms:
Body Weight
Signs and Symptoms processed this record on May 24, 2017