The Metabolic Effects of a High Fructose Versus a High Glucose Diet in Overweight Men

The protocol will assess the following outcomes:

• The ultimate fate of this increased hepatic fatty acid production following a high fructose vs. glucose diet
• The effect of a high fructose vs. glucose diet on liver ATP stores
• The effect of a high fructose vs. glucose diet on markers of oxidative stress
• The effect of a high fructose vs. glucose diet on cardiovascular status

Factors critical to carbohydrate metabolism such as systemic insulin resistance, body composition, energy expenditure, physical activity will also be assessed.

32 centrally overweight healthy males with a low baseline fructose intake will be recruited. They will be randomised double blindly to receive 25% of their dietary energy requirements from either fructose or glucose for 14 days.

The sugars will first be taken in an energy balanced and then an overfeeding setting.

Inclusion criteria

• Body mass index 25-32
• Waist > hip circumference
• Age 18-50 years
• Male

Exclusion criteria

• Reported weight change > 3 kg in prior 3/12
• Active health problems
• Contraindications to MRI scanning
• Symptoms of functional bloating or irritable bowel syndrome
• Abnormal liver or renal function tests
• Random glucose greater than 11.0 mmol/L
• Evidence of metabolic or viral liver disease as screened for by hepatitis B and C serology, and ferritin.
• Alcohol intake > 21 units per week
• Vegetarianism
• Normal daily fructose intake from drinks greater than that in 500ml of coca cola
• Abnormal carbohydrate energy contribution to baseline diet - defined as greater than 2 standard deviations from the mean of the National Diet and Nutrition Survey 2002 data