• Hypothesis 3: Ls and Lm will result in lower insulin sensitivity (frequently sampled i.v. glucose tolerance test [FSIVGTT] and meal tolerance test [MTT]) than Ns and Nm (Ns/Nm>Ls/Nm≥Ns/Lm>Ls/Lm). Sleep and meal timing will have independent and interactive effects on the 24-h pattern of hormones regulating food intake (lower leptin and glucagon-like peptide-1 [GLP-1]; higher ghrelin, NPY and hypocretin-1).