For how to write research papers, it's best to take a course on research writing.
Also read lots of medical research papers, these will give you an idea of how to set up your research, and how to collect and analyze data, and what points and how to discuss your results.
For references, I suggest you start your search with sites like
Medline,
PubMed, NIH, CDC,
ABSB, and other like medical sites, to name a few--not commercial sites, but sites oriented towards the medical professionals.
Last but not least, congratulatiosn on your successful weight loss so far! Keep up the good work