28:T4cc,

Animal and human studies indicate that high saturated fat (SFA) diets can be obesogenic. Monounsaturated fat (MUFA) has acute (meal related) effects that influence energy metabolism. These include increased postprandial fat oxidation and greater diet induced thermogenesis, factors that attenuate weight gain. Chronic (diet related) studies for 12 weeks or more, demonstrate that people following high MUFA diets do not gain excessive weight even when eating ad libitum. In fact, we have observed greater body weight and fat loss in men following an ad libitum MUFA diet, when compared to a SFA diet. High MUFA diets designed for weight loss should also incorporate a high vegetable intake according to traditional Mediterranean patterns. Such diets will promote the utilisation of fat and also have a low energy density. In our experience these diets are well accepted, and offer the prospect of greater long-term adherence to dietary advice.

29:T461,

The Body Mass Index (BMI) has been used worldwide as an indicator of fatness. However, the universal cut-off points by the World Health Organisation (WHO) classification may not be appropriate for every ethnic group when consider the relationship with their actual total body fatness (%BF). The application of population-specific classifications to assess BMI may be more relevant to public health.

Ethnic differences in the BMI-%BF relationship between 45 Japanese and 42 Australian-Caucasian males were assessed using whole body dual-energy X-ray absorptiometry (DXA) scan and anthropometry using a standard protocol.

Japanese males had significantly (p<0.05) greater %BF at given BMI values than Australian males. When this is taken into account the newly proposed Asia-Pacific BMI classification of BMI >23 as overweight and >25 as obese may better assess the level of obesity that is associated increased health risks for this population. To clarify the current findings, further studies that compare the relationships across other Japanese populations are recommended.

2a:T499,

Obese insulin resistant individuals often present with a dyslipidemic phenotype characterised by hypertriglyceridemia, low HDL cholesterol levels, essentially normal total- and LDL-cholesterol, but a propensity for smaller, denser LDL particles. We have reported that concentrations of chylomicrons are two to three folds greater than in age-matched lean controls. We have recently observed that in lean free-living subjects the flux of chylomicrons over a 12h period was just 25% greater in these subjects than basal chylomicron production. Constitutive secretion of chylomicrons appears to be of greater relevance to arterial exposure than postprandial fluctuations. Insulin critically regulates the metabolism of very low density lipoprotein (VLDL) and hence it would be expected that the hormone is also involved in the regulation of chylomicron metabolism. Impaired insulin action may therefore be responsible for the associated hyperchylomicronaemia. In this review we examine the hypothesis that insulin chronically modulates chylomicron metabolism and present evidence suggesting that hyperchylomicronaemia primarily results from impaired chylomicron production.

2b:T569,