Bodily fluid analysis system capable of assessing effect of gut health on weight loss or other health program

A breath analysis system, comprising:

• a breath analysis device including a sensor system comprising one or more sensors positioned along a flow path configured to measure, in a breath exhaled by a human subject, at least (1) acetone and (2) a gut biomarker;
• and
• a processing system comprising one or more hardware processors, the processing system configured to:
• receive measurements generated by the sensor system of at least acetone and the gut biomarker in the breath;
• determine a user-specific gut biomarker threshold for the gut biomarker based on a plurality of measurements of the gut biomarker received over a time period;
• use at least a measurement of the gut biomarker to make a determination of whether a measurement of acetone was generated at a point in time during which the human subject's breath acetone level corresponds to a level of fat metabolism in the human subject;
• and
• responsive to a determination that the measurement of acetone was generated at the point in time during which the human subject's breath acetone level corresponds to the level of fat metabolism:
• select a diet plan from a plurality of diet plans that would maintain the human subject's breath acetone level at a target acetone level and below a maximum acetone level while maintaining the gut biomarker below the user-specific gut biomarker threshold, wherein the selected diet plan does not maximize acetone levels of the human subject;
• and
• output the selected diet plan.