Overweight and obesity is one of the risk factors for developing CVD. At present, very little is known about the acute effects of dietary fibre on lipids, glucose and insulin, resting energy expenditure and diet-induced thermogenesis in overweight and obese individuals. This study examined the postprandial metabolic effects of dietary fibre in overweight and obese men. Ten overweight and obese men consumed a mixed meal accompanied by either a high-fibre or low-fibre supplement on two separate visits, in a random order, 1 week apart. Two isoenergetic breakfast meals with similar composition were consumed by ten overweight/obese men. The meals contained either a low (3 g) or high (15 g) amount of fibre, low-fibre meal (LFM) and high-fibre meal (HFM) respectively. Analysis was carried out using paired t test and ANOVA. Serum TAG incremental area under the curve during 6 h of the postprandial period was significantly lower after the consumption of HFM compared with LFM. At the first hour of the postprandial period, plasma apo B48 concentration after consumption of HFM was significantly lower compared with LFM. The resting energy expenditure and diet-induced thermogenesis after both meals was similar during 6 h of the postprandial period. Collectively, these findings suggest that a single acute dose of dietary fibre in the form of psyllium supplement can decrease arterial exposure to TAG and modify chylomicron responses in the postprandial period.Psyllium: Obesity: Postprandial state: Lipids: Lipoproteins: Thermogenesis Overweight and obesity is one of the important risk factors in the development of CVD. Atherosclerosis is the main cause of CVD. Several lipoprotein types probably contribute to the initiation of atherosclerosis, including LDL and chylomicron remnants (CMR) (1,2) . Under normal conditions, CMR are rapidly cleared from plasma predominantly via the LDLreceptor during the postprandial period. However, in the case of obesity, increased production and/or impaired clearance of these particles results in elevated plasma levels of postprandial chylomicrons and CMR (3) . Studies have also identified apo B48 as a marker of chylomicrons and CMR in femoral and carotid biopsies of human atherosclerotic plaque (4 -6) . Furthermore, studies have shown an increase in plasma CMR in subjects with or at risk of atherosclerosis (7,8) . As postprandial dyslipidaemia is an independent risk factor for atherosclerosis and CVD (8 -11) , this phenomenon may be an additional cause of rapid progress of atherosclerosis among overweight and obese individuals.Epidemiological studies have demonstrated that the prevalence of obesity is lower in populations that consume high-fibre diets compared with populations that consume low-fibre diets (12 -14) . Similarly, within population groups, individuals with a higher fibre intake tend to be leaner than individuals with a lower fibre intake and case-control studies have documented that obese individuals typically consume less fibre than normal-weight individuals (14 -16) . The main rat...