A new study by Erica Schulte, Nicole Avena and Ashley Gearhardt used an MTurk sample to study whether certain foods trigger addiction. The study does a nice job of describing the participants:
In study two, 398 participants were recruited using Amazon’s Mechanical Turk (MTurk) worker pool to complete a study about eating behaviors. Participants were aged 18 to 64 years with a mean age of 31.14, 59.4 percent were male, 76.8 percent were Caucasian, 12 percent were Asian or Pacific Islander, 8.9 percent were African-American, 6.5 percent were Hispanic, and 2.8 percent were Other. BMI, as calculated by self-reported of height and weight, ranged from underweight to obese.
This pool is younger and somewhat more male than the average American.
Ethnicity, though — this is very close to US averages. A bit low on the African Americans and Hispanics and a bit high on the Asians and Caucasian, but different than the ‘young white guy’ profile that many talk about.