Effect of Sucrose on Liver Fat

DESIGN Randomized, cross-over design with two 7-day dietary interventions separated by a 4 week wash-out period. Dietary intervention will be based on iso-energetic substitution of sucrose for starch in a weight-maintaining diet. The two experimental conditions are: high sucrose diet at 25% of total energy intake (this is approximately the 95th percentile for UK intake of non-milk extrinsic sugars (NMES)); and low sucrose diet at 10% of total energy intake. Otherwise the macronutrient balance in both conditions will be based on UK average habitual intake.

POPULATION 10 healthy males aged between 20 and 40 years, with a BMI between 20-25kg/m2, with normal liver fat levels (<5%) and fasting plasma glucose and no evidence of insulin resistance will be recruited. No pre-existing morbidity including cardiac, hepatic or renal disease, history of diabetes, hypertension or hyperlipidemia. Usual physical activity of subjects to range from sedentary to a maximum of meeting the UK minimum activity recommendations (30 min moderate exercise 5 d/week). Habitual alcohol intake of less than 2 units per day.

TREATMENT Pre-intervention: Participants will be asked to record habitual dietary intake by completion of a 7-day food diary and be asked to wear an accelerometer armband to assess physical activity before each intervention week. Resting energy expenditure will also be assessed by indirect calorimetry.

7 day dietary interventions: Participants will be resident at the clinical research facility at Hammersmith Hospital during each intervention week for 5 out of the 7 days and all food will be provided at the facility. At the weekends, participants will have to leave the unit but food will be provided for those two days so that the diet can be continued at home.

At the start and end of each 7 day intervention: Weight, height and waist circumference will be taken; percentage liver fat and total and regional body composition will be measured by MRI. Fasting and post prandial plasma glucose, insulin and lipids will be measured and blood pressure.