TY  - JOUR
AU  - Yeshurun, Shlomo
AU  - Cramer, Tomer
AU  - Souroujon, Daniel
AU  - Mor, Merav
PY  - 2024
DA  - 2024/4/1
TI  - The Association of Macronutrient Consumption and BMI to Exhaled Carbon Dioxide in Lumen Users: Retrospective Real-World Study
JO  - JMIR Mhealth Uhealth
SP  - e56083
VL  - 12
KW  - app
KW  - applications
KW  - association
KW  - BMI
KW  - body mass index
KW  - carbohydrate
KW  - carbon dioxide
KW  - consumption
KW  - correlate
KW  - correlation
KW  - diet
KW  - dietary
KW  - exhalation
KW  - exhale
KW  - food
KW  - Lumen
KW  - macronutrient
KW  - meal
KW  - metabolic flexibility
KW  - metabolic
KW  - metabolism
KW  - mHealth
KW  - mobile health
KW  - nutrient
KW  - nutrition
KW  - nutritional
KW  - obese
KW  - obesity
KW  - postprandial
KW  - prandial
KW  - retrospective
KW  - weight
AB  - Background: Metabolic flexibility is the ability of the body to rapidly switch between fuel sources based on their accessibility and metabolic requirements. High metabolic flexibility is associated with improved health outcomes and a reduced risk of several metabolic disorders. Metabolic flexibility can be improved through lifestyle changes, such as increasing physical activity and eating a balanced macronutrient diet. Lumen is a small handheld device that measures metabolic fuel usage through exhaled carbon dioxide (CO2), which allows individuals to monitor their metabolic flexibility and make lifestyle changes to enhance it. Objective: This retrospective study aims to examine the postprandial CO2 response to meals logged by Lumen users and its relationship with macronutrient intake and BMI. Methods: We analyzed deidentified data from 2607 Lumen users who logged their meals and measured their exhaled CO2 before and after those meals between May 1, 2023, and October 18, 2023. A linear mixed model was fitted to test the association between macronutrient consumption, BMI, age, and gender to the postprandial CO2 response, followed by a 2-way ANOVA. Results: The model demonstrated significant associations (P<.001) between CO2 response after meals and both BMI and carbohydrate intake (BMI: β=–0.112, 95% CI –0.156 to –0.069; carbohydrates: β=0.046, 95% CI 0.034-0.058). In addition, a 2-way ANOVA revealed that higher carbohydrate intake resulted in a higher CO2 response compared to low carbohydrate intake (F2,2569=24.23; P<.001), and users with high BMI showed modest responses to meals compared with low BMI (F2,2569=5.88; P=.003). Conclusions: In this study, we show that Lumen’s CO2 response is influenced both by macronutrient consumption and BMI. The results of this study highlight a distinct pattern of reduced metabolic flexibility in users with obesity, indicating the value of Lumen for assessing postprandial metabolic flexibility. 
SN  - 2291-5222
UR  - https://mhealth.jmir.org/2024/1/e56083
UR  - https://doi.org/10.2196/56083
UR  - http://www.ncbi.nlm.nih.gov/pubmed/38439744
DO  - 10.2196/56083
ID  - info:doi/10.2196/56083
ER  -