Peptide hormones, which regulate appetite, energy expenditure and glucose homeostasis, are released from the gastrointestinal tract in response to nutrients and they communicate information to the brain regarding the current state of energy balance. They can act on target peripheral tissues through circulation by either activating the vagus nerve or by activating the hypothalamus and brainstem so that are implicated in energy homeostasis. An overview of the main gut hormones implicated in the regulation of food intake and how some of these hormones are being targeted to develop anti obesity treatments are discussed in this review.