There are clear why protein drinks like isopure, 24 hours before a colonoscopy, because they are clear, can they be consumed? protein is healthier and more filling. my pc prefers me to not drink sugars in fruit juices or in sprite(nor the co2)?

You do not need to eat clear liquid diet or avoid most fruit juices or soda for colonoscopy preparation. The most important tasks are eating low residue foods and avoiding red or purple (food dye) colored drinks or foods. Clear liquid diet 24 hours before the procedure is no longer recommended. Please read this link: https://www.colonoscopy.com/procedures/best-diet-for-48-hours-before-colonoscopy/

One day of not consuming enough protein will not affect your health in any way. You should follow the instructions that your doctor gives you with the colonoscopy. Do not worry about your protein intake that day. You can resume normal diet afterwards. Good luck on your colonoscopy!