Abdominal obesity is strongly associated with dyslipidemia, which may account for the associated increased risk of atherosclerosis and coronary disease. Weight reduction is suggested to be a preferred and effective first-line strategy to correct lipid abnormalities, particularly in overweight/obese subjects. This improvement may be related to the effect of reduction in abdominal fat mass on apoB and apoA-I metabolism, but this remains to be fully demonstrated.

Hypothesis: Reduction in abdominal fat mass by weight loss decreases apoB concentration and raises HDL-cholesterol chiefly by increasing LDL-apoB fractional catabolic rate (FCR), as well as decreasing HDL apoA-I, respectively.

We examined the mechanism of the effect of weight loss through dieting on LDL and HDL metabolism in abdominally obese men. LDL apoB-100 and HDL apoA-I kinetics were studied using a primed-constant infusion of 1-[13C]-leucine in a controlled, dietary intervention trial of 16 weeks duration in middle-aged, obese men with the metabolic syndrome. Isotopic enrichment in apoB and apoA-I was measured by gas chromatography-mass spectrometry and fractional turnover rates estimated using multi-compartmental modelling.

Inclusion Criteria:

• Obesity was defined as a body mass index (BMI) >28kg/m2 and visceral visceral obesity (waist to hip ratio> 1.0 or waist circumference >100 cm)

Exclusion Criteria:

• Diabetes mellitus,
• Proteinuria,
• Hypothyroidism,
• Abnormal liver enzymes,
• Major systemic illness,
• A history of alcohol abuse,
• A family history of hyperlipidemia or premature coronary artery disease or were taking medication known to affect lipid metabolism.