Provided herein are peptides and peptide analogs and methods of treating a metabolic disease, e.g., obesity, diabetes, methods of treating cancer, methods of treating a liver disease, and methods of modulating fatty acid metabolism.在此所提供係肽及肽類似物、以及治療代謝疾病(例如,肥胖病、糖尿病)之方法、治療癌症之方法、治療肝病之方法、以及調節脂肪酸代謝之方法。