1994 paper dietary factors in the management of parkinson's using l-dopa
 

http://apjcn.nhri.org.tw/server/Mark...01994/P182.pdf

not sure if everything presented here is still accurate but if it is has some good ideas of how to try to minimize protein interference, increase l-dopa getting to the brain.

also discusses fava and mucana as options for 3rd world, gives l-dopa content.

here's a good explanation as to why you want to minimize the time l-dopa stays in your stomach:
l-dopa is otimally absorbed from the duodenum and proximal jejunum. the drug is not absorbed across the gastric mucosa, but oral doses are dependent upon gastric emptying for access to absorption sites. the rate of gastric emptying is chiefly determined by the energy content of food and is inversely proportional to the energy density of the meal. thus fat will retard gastric emptying to a greater degree than carbohydrates or protein. low gastric acidity slows emptying although routine administration of antacids to pd patients doesn't improve l-dopa absorption. some types of dietary fiber increase food viscosity and slow gastric emptying. THE GASTRIC MUCOSA CONTAINS THE ENZYME DOPA DECARBOXYLASE, WHICH WILL CATALYZE UNWANTED CONVERSION OF L-DOPA TO DOPAMINE, REDUCING THE AMOUNT OF L-DOPA AVAILABLE FOR SUBSEQUENT ABSORPTION FROM DOSES AFFECTED BY DELAYED GASTRIC EMPTYING.

remember, dopamine doesn't cross the BBB which is why we take l-dopa.

diet and PD
 

There was a neuropharmacologist at MIT, named Richard Wurtman, [now retired]who did a lot of animal studies on dietary protein and its' direct effect on neurotransmitter levels in the brain. He was somewhat controversial about 30 years ago when I first heard of him. He is married to a nutritionist, Judith Wurtman. Richard was supposed to have come up with a diet for Parkinsons, based on a protein/carb ratio of 1:5 if I recall correctly. He didn't recommend low protein diets, or restricting protein to just the evening meal. I see references to a book published by him on the topic, but I cant locate it anywhere. The nutritionist for the National Parkinson Foundation site, Kathrynne Holden, recommends a ratio of protein/carb of 1:7, which seems high in carbs to me. What and when to eat is a major problem for some of us using frequent doses of sinemet. Also, unexplained weight loss is major problem for some PD patients, mostly women, as I recall.
It would be nice is someone (?) would coordinate studies on this mundane issue and come up with some real information that helps people.