INS and obesity due to melanocortin 4 receptor deficiency: McKay et al. (2018) fed people who were overweight or had obesity (n = 26) either pecan nuts (~42.5 g) or a fiber/calorie matched control for 4 weeks and reported no difference between the groups on fasting glucose, while insulin concentrations, insulin resistance (HOMA-IR), and beta cell function (HOMA-β) were significantly improved compared to the control diet [69].