NOTCH1 and obesity due to melanocortin 4 receptor deficiency: To investigate whether Notch1 haploinsufficiency is associated with obesity, we fed 4-week-old male Notch1 heterozygous-deficient (N1+/−) mice and their WT counterparts high-fat high-sucrose (HF/HS) or normal diet, respectively, and measured body weight and daily food intake for 12 weeks.