On the other hand, when protein hits the stomach, it releases gastric acid to digest it. Eating protein and starches at the same time releases both alkaline and acid, which neutralizes incompletely digested foods and allows them to ferment in your digestive system. This causes gas. In addition, incompletely digested protein molecules can be released into the bloodstream causing allergic reactions. Lastly, because the stomach does not empty quickly, constipation ensues.
Many people argue that a lot of foods contain both starch and protein.
This is true. Dried beans or peas are the exception and should be avoided or soaked to render them starchless. Fruits are a bit tricky as well. Eat bananas, yellow pears, grapes, dates and figs with starch meals. All other fruits should be eaten with protein meals.