Protein elicits a stronger early (30 min) glucose‐dependent insulinotropic polypeptide (GIP) response than fat ingestion in lean individuals, with no difference in glucagon‐like peptide‐1 (GLP‐1). We assessed the incretin hormone response to protein versus fat ingestion in obesity. Equicaloric (8 kcal/kg) fat (olive oil) or protein (whey protein) was ingested by non‐diabetic obese male volunteers [body mass index (BMI) >30 kg/m2; n = 12] and plasma GIP and GLP‐1 were determined. We found no difference in the early GIP or GLP‐1 responses to fat versus protein. However, the total 300‐min GIP response was greater after fat than after protein ingestion (20.3 ± 3.9 vs. 10.0 ± 2.8 nmol/l × min; p = 0.026), whereas the 300‐min GLP‐1 responses were the same. Thus, in obesity, protein and fat ingestion elicit similar early (30 min) incretin hormone responses, whereas 300‐min GIP secretion is more pronounced after fat than protein ingestion.