BACKGROUND: Enhanced postprandial lipaemia has been reported in patients with obesity, hypertension, metabolic syndrome and type 2 diabetes mellitus (T2DM). We compared 2 oral fat meal tests (LIPOLD: 149g of fat, 56g of carbohydrates and 11.7g of proteins administrated per 2m2 of body surface) and LIPOTEST: 75g of fat, 25g of carbohydrates and 10g of protein with the addition of 15g common sugar) with regard to changes in triglycerides (TGs) as well as other cardiometabolic parameters between baseline and 4 h after the meals. METHODS: We studied 21 men [median age (interquartile range; IQR) = 65 (16) years] with well-controlled T2DM [median glycated haemoglobin (HbA1c) (IQR) = 6.6 (0.9) %]. All participants performed the meals with 1 week interval between the 2 meals. RESULTS: Median (IQR) TG differences in mg/dl were 86 (100) and 46 (60) for LIPOLD and LIPOTEST meals, respectively, whereas the % differences in TGs were 105 (105) and 48 (55), respectively. The differences (in mg/dl and %) between TGs before ingesting the test meal and after 4h were significant for both LIPOLD and LIPOTEST meals (p = 0.003 for mg/dl differences and p = 0.005 for % differences). Patients who had a positive response to the LIPOLD meal (i.e. TGs > 220 mg/dl at 4 h) also had increased postprandial TGs with LIPOTEST. The Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) correlated with TG differences (in mg/dl) following the LIPOLD meal consumption (Spearman's rho = (+) 0.527, p = 0.02). C-peptide correlated with TG differences (in mg/dl) following the LIPOTEST meal consumption (Spearman's rho = (+) 0.538, p = 0.032). There were no differences in TGs and glucose response postprandially in both testing meals according to body mass index (except for TGs between tertile 21.3-24.5 and 25-26.8 kg/m2, p=0.046, in LPOTEST group) and body surface area. CONCLUSION: An oral fat tolerance test (OFTT), which contains 75g fat, and represents the everyday habits of Western societies, could provide additional information regarding the postprandial state of the individuals with well-controlled T2DM. The consumption of meals with very high fat content may lead to over diagnosing PPL. TG differences after the consumption of a high fat meal correlated with HOMA-IR. This may be useful to evaluate the role of HOMA-IR in T2DM patients. A standardized the OFTT will help clinicians to better define postprandial TG abnormalities, leading to more appropriate therapeutic options to improve postprandial dysmetabolism.