Sex differences in exogenous glucose oxidation are attenuated by obesity: insights from a [U- ¹³ C ₆ ]glucose home breath test

]glucose breath test during a 3-h OGTT, we show that normal-weight females oxidize a greater proportion of ingested glucose than males despite similar blood glucose and insulin responses. This sex difference is attenuated in obesity, which reduces overall glucose oxidation. These findings reveal sex-specific regulation of postprandial glucose metabolism not captured by conventional OGTT metrics and highlight breath testing as a sensitive, noninvasive approach for assessing glucose metabolism outside the laboratory.