The study looked at eight people aged 16 to 63 who have urea cycle disorders (UCD). Researchers wanted to see if taking pictures of meals with a phone app was easier and more accurate than writing down foods on paper for three days. Both methods were compared to a scientific test called doubly labeled water, which measures how many calories a person uses. Participants were weight-stable and included people with OTC deficiency, ASS1 deficiency, and ASL deficiency. The goal was to find a better way to measure diet since nutrition is a key part of UCD care.
Key Takeaways
Both Methods Underreported Calories: On average, people reported eating 16% fewer calories with paper records and 22% fewer calories with the photo app compared to their actual energy use. This means neither method was fully accurate.
Protein Intake Was Similar Across Methods: Protein made up about 13% of calories with paper records and 15% with the app, which is close to normal diets. Most participants met or exceeded daily protein recommendations, even though they were told to limit protein.
No Big Difference in Macronutrients: Carbohydrate and fat intake were similar between the two methods. Both methods showed diets that looked like typical U.S. eating patterns: about 50% carbs and 37–38% fat.
Participants Preferred the App Slightly: About 67% of participants liked the photo app better for recording meals, but overall ease-of-use scores were similar for both methods.
Day-to-Day Eating Was Consistent: People tended to eat similar amounts of calories and protein each day, showing that UCD diets may be more repetitive than typical diets.
Why This Matters
Tracking diet is important for managing UCD, but this study shows that current methods still miss details. Understanding these limits helps researchers and clinicians improve tools for monitoring nutrition in people with UCD.
Sim E, Gregor A, MacLeod E, Moore R, Ravelli MN, Schoeller DA, Harding CO, Jacobs P, Gillingham MB. Measuring dietary intake among participants with a urea cycle disorder using standard diet records or a novel food photography app. Mol Genet Metab. 2025 Nov 12;146(4):109291. doi: 10.1016/j.ymgme.2025.109291. Epub ahead of print. PMID: 41242089.
