Introduction: It is well known that exhaled breath composition is instant reflection of the organism since volatile metabolites tend to move from the blood into the air in the lungs. Therefore, breatholomics is becoming very popular as а new non-invasive screening diagnostic tool. This research brings a portable, low-cost screening sensor prototype based on membrane-inlet mass spectrometry (MIMS) for food impact assessment, by tracking changes of volatile organic compounds (VOCs) in exhaled breath. Analytes of interest are breath VOCs that are related to the metabolism of the main food constituents. Methods: 150 exhaled breath samples were collected from 50 adult healthy volunteers with informed consents and ethical approval completed (Approval No. 2021-01-3/70-1). Each participant provided a sample before meal (after 12h fasting period), 60 min and 120 min after the meal. All samples were analyzed using MIMS system for selected VOC mass fragments – m/z 58 for acetone, m/z 42 for n-pentane, m/z 45 for ethanol and m/z 67 for isoprene. Sample introduction was done using PDMS sheet membrane probe heated at 70◦C. VOC gas standards were prepared by static dilution technique and used for quantification. Results: Significant change (more than 10% increment or decrement) upon meal consumption was observed in ~85% of participants for acetone and ethanol, ~70% for n-pentane and ~50% for isoprene. Changes in selected analytes’ signals were compared for 60min and 120min after the meal, and greater change was observed 120 min after the meal for all analytes, except for ethanol. Obtained mean values for acetone, ethanol, n-pentane, and isoprene respectively were: 809 ppb, 488 ppb, 30 ppb and 70 ppb in samples before meal, 875 ppb, 532 ppb, 29 ppb and 68 ppb in samples collected 60 min after the meal and 559 ppb, 474 ppb, 27 ppb and 66 ppb in samples collected 120 min after the meal. According to the results obtained, it can be said that MIMS system used in this study could be employed in food impact assessment by analyzing breath VOCs. It has been established that major food impact can be monitored 120 min after the meal for analyzed mass fragments. Additionally, obtained mean values were ranked in expected order of magnitude and not surprisingly – the most significant food impact was observed for acetone. Further research will include more participants with different nutritional and health backgrounds, which will expand the knowledge in this area. Novel Aspect: Employment of portable MIMS system in food impact assessment offers a great advantage for possible preventive screening analyses that would provide an alert for nutritional imbalances.