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Completed

NCT Number: NCT04037020

The Chocolate Study 2.0

The purpose of this study is to test how the brain responds when enjoyable foods such as chocolate are consumed. The investigators know that eating certain types of foods can make an individual want to keep eating even when he or she is full. The chemical in the brain that causes this is called dopamine. The investigators can measure this response by looking at changes to how an individual's eye responds to light.

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Key information

Conditions

Normal Weight

Age range

18 year–30 year

Sex eligibility

All sexes

Study type

Observational

Primary location

USDA Grand Forks Human Nutrition Research Center

Grand Forks, North Dakota, 58203, United States

About this study

The overall objective of this study is to determine dopamine (DA) neuromodulation (changes in b-wave amplitude as measured by electroretinography (ERG)) in response to consuming a highly reinforcing food (chocolate). The investigators hypothesize that orosensory stimulation with chocolates with increasing sugar content will increase the beta wave (b-wave) amplitude and the increase in the b-wave amplitude will correlate with score changes on the Psychophysical Effects Questionnaire (PEQ). This will be accomplished by testing different chocolates (extreme dark (90% cocoa), dark (70% cocoa), milk (38% cocoa), and white (0% cocoa)) on different days using 1.0 cd∙s/m2 flash luminance energy.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • BMI 20-24.9 kg/m2
  • ability to understand and sign the consent form
  • availability of transportation (i.e., participants must be able to provide their own transportation to the Grand Forks Human Nutrition Research Center)
  • be free of any major illness/disease

Exclusion criteria

  • food allergies
  • participation in a weight loss diet/exercise program
  • pregnancy
  • lactation
  • metabolic illness/disease (diabetes, renal failure, thyroid illness, hypertension)
  • eye illness/disease (narrow angle glaucoma, macular degeneration, retinal detachment, cataracts)
  • psychiatric, neurological or eating disorders (schizophrenia, depression, Parkinson's Disease, Huntington's Disease, cerebral palsy, stroke, epilepsy, anorexia nervosa or bulimia nervosa)
  • taking any type of prescription medication with the exception of oral contraceptives and antihyperlipidemia agents

Treatment and study plan

Chocolate

Other

Participants will be asked to taste commercially available chocolate varying in sugar, fat and percent cocoa (extreme dark (90%), dark (70%), milk (38%), and white (0%)).

Primary outcomes

  1. Retinal dopamine response to oral stimuli

    Time frame: 30 minutes

    Electroretinograph b-wave amplitude will increase in response to increases in the amount of sugar in the chocolate.

Secondary outcomes

  1. Correlation between b-wave amplitude and PEQ scores

    Time frame: 30 minutes

    The change in b-wave amplitude will positively correlate to Psychophysical Effects Questionnaire (PEQ) score changes.

  2. Correlation between b-wave amplitude and habitual dietary intake

    Time frame: 30 minutes

    A preference for dark chocolate and/or a greater habitual fat intake will positively correlate with the retinal dopamine-mediated response to the dark chocolates (90% and 70% cocoa) and a preference for milk chocolate and/or a greater habitual added sugar will positively correlate with the retinal dopamine-mediated response to the milk and white chocolates. Higher amounts of artificial sweetener intake will will positively correlate with the retinal dopamine-mediated response to the milk and white chocolates. Greater habitual chocolate intake will positively correlate to changes in b-wave amplitude.

Sponsors and collaborators

Lead sponsor

USDA Grand Forks Human Nutrition Research Center

Fed

Registry information

Official study title

Assessment of Dopaminergic Neurotransmission in Response to Tasting Chocolate (The Chocolate Study 2.0)

Important dates

Study start
2019
Primary completion
2019
Study completion
2019
First posted
Jul 30, 2019
Registry last updated
Apr 11, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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