The Chocolate Study 2.0

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

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

Conditions
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Normal Weight

Intervention / Treatment
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* Other: Chocolate


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Chocolate<br>Participants will be asked to taste commercially available chocolate varying in sugar, fat and percent cocoa. | Other: Chocolate<br>* 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%)).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Retinal dopamine response to oral stimuli | Electroretinograph b-wave amplitude will increase in response to increases in the amount of sugar in the chocolate. | 30 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation between b-wave amplitude and PEQ scores | The change in b-wave amplitude will positively correlate to Psychophysical Effects Questionnaire (PEQ) score changes. | 30 minutes | 
| Correlation between b-wave amplitude and habitual dietary intake | 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. | 30 minutes |