Substituting Lean Beef for Carbohydrate in a Healthy Dietary Pattern Does Not Adversely Affect the Cardiometabolic Risk Factor Profile in Men and Women at Risk for Type 2 Diabetes.

backgroundObservational evidence suggests that red meat intake is associated with type 2 diabetes (T2D) and cardiovascular disease incidence, but few randomized controlled trials have assessed effects of lean, unprocessed red meat intake on insulin sensitivity and other cardiometabolic risk factors.

objectiveThis study compared the USDA Healthy US-Style Eating Pattern, low in saturated fat and red meat (<40 g/d red meat; USDA-CON), with a modified version with an additional 150 g/d lean beef as an isocaloric replacement for carbohydrate (USDA-LB) on insulin sensitivity and cardiometabolic risk markers.

methodsParticipants (7 men, 26 women; 44.4 y old) with overweight/obesity [BMI (kg/m2) = 31.3] and prediabetes and/or metabolic syndrome completed this randomized, crossover, controlled-feeding trial consisting of two 28-d treatments (USDA-CON and USDA-LB) separated by a ≥14-day washout. Insulin sensitivity (primary outcome variable), lipoprotein lipids, apolipoproteins (apoA-I and apoB), and high-sensitivity C-reactive protein (hs-CRP) (secondary outcome variables), in plasma or serum, and blood pressures were assessed at baseline and the end of each diet period.

resultsUSDA-LB and USDA-CON did not differ significantly in effects on whole-body insulin sensitivity and other indicators of carbohydrate metabolism, lipoprotein lipids, apoA-I and apoB, hs-CRP, and blood pressures. USDA-LB produced a shift toward less cholesterol carried by smaller LDL subfractions compared with USDA-CON [least-squares geometric mean ratios for LDL1+2 cholesterol of 1.20 (P = 0.016) and LDL3+4 cholesterol of 0.89 (P = 0.044)] and increased peak LDL time versus USDA-CON (1.01; P = 0.008).

conclusionsSubstituting lean, unprocessed beef for carbohydrate in a Healthy US-Style Eating Pattern resulted in a shift toward larger, more buoyant LDL subfractions, but otherwise had no significant effects on the cardiometabolic risk factor profile in men and women with prediabetes and/or metabolic syndrome.This trial was registered at clinicaltrials.gov as NCT03202680.