A---There is no scienific basis to this myth whatsoever. I work with a Naturopath who has her PhD in Nutrition and here is her advice:
Food Combining
What do you think of food combining?
I am fairly open-minded and do not want to quickly dismiss any idea that may help someone to enjoy better health. And there are people who claim to experience health improvements such as better digestion when they watch how they combine their foods.
However, there is no reliable scientific evidence, of which I am aware, that shows that food combining by itself, causes health improvement. The organizations and professionals that are promoting food combining are advocating a diet that is very healthful and represents a major improvement over the Standard American Diet. Most people would experience better health consuming it regardless of the combinations used to construct the meals.
I will continue to be open to some evidence indicating that we should consider incorporating this concept into our curriculum, but for now, getting people to convert to the plant based (90%) diet we recommend is enough of a shift for most people. *****
As for acid/alkaline, yes, foods have those properties. What it means tho, is this. Our bodies function best with slightly alkaline blood. To enable our bodies to be slightly alkaline, we need lots and lots of fruits and veggies. Anything else, meat, dairy, grains...all promote acidity in the body. An acid body is vulnerable to diseases...cancer, heart disease, autoimmune disorders, etc.
So, simply eat a broad range of fruits and veggies, whole grains, legumes/beans, and a few nuts and seeds (sparingly...they contain lots of fat) while minimizing animal protein and that includes dairy and yogurt. Go to www.pcrm.org to learn why. While at the website, put dairy in the search box.
Feel free to call if you have any other questions. I'd be honored to help. D.