Can I deduct per diem meal allowance for days spent away in clinical trials for healthy adults?

 Its my main source of income. it isnt for medical purposes as i am healthy and gaining no benefit medically. i am only receiving stipend in return for offering my services and receive 1099 end of year from each site just like any self employed independant contractor.

i spend 1 to 2 weeks at each site and return home. can i deduct the meal per diem on the days i spend at the unit as well? or only days spent travelling from and to my house / the clinical trial in relation to each site? I have receipts to prove where i was and for how long. Also forms describing time spent at each study site, Each site is over 150 miles from my home ....where my home office is housed which is where i conduct the scheduling of each of my temporary "work assignments" and also where i conduct transcription for clients from time to time as a seperate form of income.

I have receipts to prove where i was and for how long. Also forms describing time spent at each study site