Our study suggests that reducing GI or %carb share a common pathway for affecting eGFRcys (Additional file 1: Figure S2). These changes are independent of markers of plasma glucose homeostasis, endothelial function, and inflammation, implying that dietary carbohydrates may have a direct effect on glomerular filtration [33]. We suspect that these short-term increases in glomerular filtration from reducing GI and/or %carb, represent hyperfiltration, a maladaptive response to abnormal renal hemodynamics and a harbinger of kidney injury and kidney disease progression [34, 35]. The long-term impact of these short-term changes in eGFRcys on clinical
outcomes is unknown. Novel markers of kidney injury in urine [36] may help elucidate the benefit or harm of dietary carbohydrates in future studies.