I read some years ago, before PD that having a glass of lemon juice first thing on waking and then having 2 kiwi fruit immediately along with 1 - 2 glasses of water at least 1/2 hour before solid food breakfast cleanses the liver and bowel. In the morning our bowel is at its optimum for clearing, and as fruit takes only 20 minutes to go through our stomach, it helps with that process. Solid foods like toast, weetbix etc take 4 hours to go through our digestive system and if mixed with the fruit at the same time, the fruit will then take 4 hours to go through our system, often causing bloating and wind as the fruit tends to ferment.
I thought this was an interesting opinion so decided to test it. I rise every morning and have my kiwi fruit, sometimes I have lemon juice, but I always have at least 1 glass of water. I then wait 1/2 hour to 1 hour before I have oatbran and yoghurt. So far this has worked a treat for me, and if I miss a 2 days of a bowel motion, I sometimes take a small laxative that night, but I don't like doing this much as it often causes stomach cramps about 3am or so. I am a bit paranoid about "going" every day, and in the main, I do.
Thought this might be helpful. Key: wait at least 1/2 an hour after taking kiwi fruit. Other fruit may work just as well, but if it is a banana, they take 40 minutes to go through your system apparently.