Exercise Substrate Utilisation and Endurance Performance Following Short-term Manipulation of Dietary Fat Intake

University of Birmingham

Status: Unknown

Conditions: Dietary Modification

Treatments: Dietary Supplement: Normal; Dietary Supplement: Normal + Extra Fat; Dietary Supplement: High Fat

Study type: Interventional

Funder types: Other; Industry

Identifiers

NCT02568592

ERN_15-0012

Details and patient eligibility

About

The capacity to burn fat as fuel for exercise may have important implications for sporting performance, with dietary fat intake positively influencing this ability.

Endurance performance and the ability to burn fat will be measured in women runners following the consumption of 3 diets varying in the amount of fat and carbohydrate.

Full description

Dietary fat intake positively influences the ability to burn fat during exercise in women but not men, whereas carbohydrate intake negatively influences fat oxidation in both sexes. The independent nature of dietary fat intake as a predictor of the ability to burn fat in women suggests that in conditions of adequate carbohydrate intake providing additional fat may increase fat oxidation in women whereas it does not in men. It is of interest to explore if indeed women are responsive (i.e., increase in fat oxidation) to short-term increases in dietary fat intake induced by overfeeding (adequate carbohydrate) or if as appears to be the case in men reduced carbohydrate intake as typically employed in high-fat, low carbohydrate dietary studies is also a prerequisite for enhancing fat oxidation in women, and whether this translates into a difference in exercise endurance performance.

Enrollment: 16 patients

Sex: Female

Ages: 18 to 45 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• BMI >17.0 < 25 kg/m2
• Good General Health
• Accustomed to vigorous physical activity
• Run > 2 times per week
• V̇O2max >50ml/kg/min
• Weight Stable > last 6months
• Non Smoker
• Pre-menopausal, and either eumenorrheic and regularly menstruating, or using monophasic hormonal oral contraceptives for > 3 months.

Exclusion criteria

• Currently taking part in another scientific/clinical study
• Taking any prescription drug / supplement thought to influence metabolism
• Following unusual dietary practices (such as intermittent fasting or low carbohydrate diets)
• Pregnant
• Breast Feeding

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: None (Open label)

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16 participants in 3 patient groups

High Fat

Experimental group

Description:

High Fat - Carbohydrate (20%), Fat (65%), Protein (15%)

Treatment:

Dietary Supplement: High Fat

Normal

Experimental group

Description:

Normal - Carbohydrate (50%), Fat (35%) and Protein (15%)

Treatment:

Dietary Supplement: Normal

Normal + Extra Fat

Experimental group

Description:

Normal + Extra Fat - Carbohydrate (50%), Fat (65%), Protein (15%). Carbohydrate and protein intake identical in absolute amounts to NORM (Normal), with an additional 30% extra energy coming from fat.

Treatment:

Dietary Supplement: Normal + Extra Fat