Full-fat versus non-fat yogurt consumption improves glucose homeostasis and metabolic hormone regulation in individuals with prediabetes: A randomized-controlled trial

Dietary guidance recommends consuming low- or non-fat dairy foods for metabolic health, yet observational research indicates full-fat yogurt intake may not detrimentally affect type 2 diabetes risk. Randomized-controlled trials are needed to further explore this relationship. Our aim was to evaluate the effect of substituting full-fat (3.25%) yogurt for non-fat yogurt on type 2 diabetes risk in individuals with prediabetes. We hypothesized beneficial effects on measures of glucose homeostasis, insulin sensitivity, and metabolic hormone response following short-term consumption of 3 full-fat yogurt servings daily. Thirteen individuals completed the 8-week randomized, double-masked crossover controlled-feeding trial comprised 2, 3-week experimental diet periods in which participants consumed 3 daily servings of full-fat or non-fat yogurt; a 1-week control preceded each diet period. Following each diet period, changes in whole-body glucose handling and metabolic hormone concentrations were measured using mixed meal and oral glucose tolerance tests. Our primary outcome measure was the blood glucose concentration at the 120-minute time point during the oral glucose tolerance test. Though differences in the primary outcome measure were not observed, the full-fat yogurt diet resulted in lower concentrations of blood fructosamine, a marker of average blood glucose concentrations over 2 to 3 weeks. Further, fasting glucagon-like peptide-1 and post-prandial glucose-dependent insulinotropic polypeptide concentrations were greater following the full-fat yogurt diet. Our preliminary results indicate that short-term consumption of full-fat relative to non-fat yogurt beneficially affected aspects of glucose homeostasis and metabolic hormone regulation in individuals with prediabetes, warranting further randomized-controlled research. This trial is registered at clinicaltrials.gov (NCT03577119).