Taking some medications with food is necessary to settle the stomach beforehand. Generally any amount of food is fine. Taking a standard over the counter stool softener shouldn't effect how any medication works.
You can ask your psychiatrist more about the specifics.
I can tell a major difference when I only consume a limited number of calories or eat the wrong food types. I have been trying to eat high-protein foods and high fiber foods together to give it maximum bioavailability and absorption in the intestines. However, I get very sleepy and feel groggy for about two hours, starting at 11 am. I take my medication 60mg @ 7:30 am-ish. I waited until 9 am to take it today to see if that helps.
When my meds make me feel groggy and sleepy, my psychiatrist has me take them at evening time, before bedtime.That works for me. When I had to switch morning dose to that. I delayed the morning dose to evening time, as dr. instructed,
I never had a problem with constipation on Geodon, but that is me. I don't really take a massive amount of fibers, just the recommended amount on average of fruits, vegetables and high fiber grains. but I also walk alot, and drink 6 to 8 glasses of water or more if I sweat alot. I eat meat, btw, also. On very rare occasions, if I am constipated for 2 days in a row, I take a fiber supplement like metamucil or senokot. Senokot is very expensive, but it works usually the next day. Metamucil usually takes a little longer. They are otc's.