Background and AimBowel preparations with polyethylene glycol (PEG) and clear fluids are often poorly tolerated. We compared an innovative low‐residue White Diet and low‐volume, split‐dose Picosalax with the standard preparation at our institution of day‐before clear fluids and combination PEG plus sodium picosulfate/magnesium citrate (SPMC).MethodsAdults undergoing morning colonoscopy were randomized to either the White Diet and split‐dose, two sachets of Picosalax (WD/PICO) or day‐before clear fluids and 1‐L PEG plus two sachets of SPMC (CF/PEG + SPMC). The primary endpoint was successful bowel preparation defined by an Ottawa bowel preparation score ≤ 6. An intention‐to‐treat analysis with a predefined non‐inferiority margin of 15% was used to compare efficacy.ResultsA total of 250 patients were randomized (125 WD/PICO and 125 CF/PEG + SPMC). WD/PICO was non‐inferior to CF/PEG + SPMC for successful bowel preparation by intention‐to‐treat analysis (58% WD/PICO vs 62% CF/PEG + SPMC, 95%CI: −14.2 to 6.2%) and per‐protocol analysis (64% WD/PICO vs 65% CF/PEG + SPMC, 95%CI: −11.3 to 9.4%). Patients in the WD/PICO group reported greater satisfaction with the diet (P < 0.001), greater ease of following the diet (P < 0.001), and improved experience compared with prior colonoscopy (P < 0.0001), less bloating (P = 0.02), less weakness (P = 0.046), less hunger (P < 0.0001), and less interference with daily activities (P = 0.001). Procedure/withdrawal times and adenoma detection rates were similar between groups.ConclusionBowel preparation with the White Diet and low‐volume, split‐dose Picosalax was preferred and better tolerated without detriment to bowel preparation success compared with clear fluids and combination PEG plus SPMC for morning colonoscopy.