Merpig,
It's not that low-carbers have to have that data already. I mistakenly thought you were saying that requiring people to monitor or report what they eat was something gimmicky or WW-like. It's just scientific studies require it. So when I was perusing 'Internet diet,' I found this and I thought it was interesting. The people who sign up to be followed don't have to have something done already. But it does require more than just people on the Internet never having to be identified by other than their online name and the information they give online:
http://www.ncbi.nlm.nih.gov/pubmed/20459807
You can read the entire study - its plan - which is presented in an article that can be downloaded as a PDF (upper right hand corner icon).
This is French and will last for 10 years. It takes 5 years for them to recruit 500,000 volunteers who have to complete baseline data.
The questionnaires will be submitted online. But, not unlike some other countries (I'm thinking of Denmark), there is a tremendous amount of information online.
'Surveillance of health events will be implemented via questionnaires on hospitalisation and use of medication, and linkage with a national database on vital statistics. Biochemical samples and clinical examination will be collected in a subsample of volunteers.'
From the PDF:
'Indeed, the use of internet offers a unique opportunity
for gaining access to a vast sample of volunteers. France
ranks in first place among European countries in use of
the internet . In November 2009, 34.7 million French
citizens (about 65% of the population over 11) had been
connected to the internet during the previous month
irrespective of the connection site (home, work, public or
private location) . One French internet user out of 4
is over 55 years of age and 29% of users belong to low
socio-professional categories . Thus, the profile of
internet users would reflect an accurate representation of
the different age groups (especially seniors), socio-professional
categories and regions. Indeed, the use of internet
offers the possibility of automatically gaining access to
immense samples of volunteers as well as gradually collecting,
saving and processing huge amounts of information
at reduced logistic burdens and costs.'