Optimized Carbohydrate Fueling to Enhance Physical Performance During Energy Deficit

Summary

This randomized crossover study will examine the effects of consuming isocaloric GLU+FRU or GLU alone on rates of exogenous carbohydrate oxidation during aerobic exercise and physical performance (time trial) under energy balance (BAL) and energy deficit (DEF). Baseline data will be collected on volunteer height, weight, body composition, and V̇O2peak. To ensure volunteers are familiar with exercise protocols, they will complete practice sessions of all exercise before the start of data collection. Exercise and diet will be controlled throughout data collection. To start the protocol volunteers will complete a bout of glycogen normalization on a cycle ergometer followed by 48 hours of refeeding at 100% (BAL) or 50% (DEF) of their energy needs. After the 48 hours of refeeding volunteers will return to the laboratory to complete 80 min of steady-state (60 ± 5% V̇O2peak) exercise on a cycle ergometer. Immediately before and during steady-state exercise, volunteers will consume either 80 g of GLU+FRU (53 g glucose + 27 g fructose) or 80 g GLU. Drinks containing corn-derived crystalline fructose (KRYSTAR® 300, Tate and Lyle Sugars, London, UK) and glucose (CERELOSE®, Ingredion, Westchester, IL, USA) will be prepared by unblinded USARIEM staff. Drinks will be enriched with 13C stable isotopes (Cambridge Isotope Laboratory, Andover, MA, USA) to measure exogenous and plasma carbohydrate oxidation during steady-state exercise. After steady-state exercise, physical performance will be assessed using a graded exercise test on a stationary bike. Indirect calorimetry and breath sampling will be used to determine substrate oxidation during steady-state exercise. Serial blood draws will be collected during each trial to assess isotope enrichments, and circulating substrate/hormone responses. Muscle biopsies will be performed before and after steady-state exercise to assess glycogen status, enzyme activity, and molecular regulation of substrate metabolism. There will be a minimum of 7 days between each carbohydrate metabolism study day.

Conditions

• Energy Supply; Deficiency

Interventions

DIETARY_SUPPLEMENT

BAL:GLU

80 g glucose consumed during steady-state exercise following 48 hours of consuming an energy balance diet

DIETARY_SUPPLEMENT

BAL:GLU+FRU

53 g glucose plus 27 g fructose consumed during steady-state exercise following 48 hours of consuming an energy balance diet

DIETARY_SUPPLEMENT

DEF:GLU

80 g glucose consumed during steady-state exercise following 48 hours of consuming an energy balance diet

DIETARY_SUPPLEMENT

DEF:GLU+FRU

53 g glucose plus 27 g fructose consumed during steady-state exercise following 48 hours of consuming an energy balance diet

Sponsors & Collaborators

• United States Army Research Institute of Environmental Medicine

  lead FED

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

TRIPLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

39 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2024-02-01

Primary Completion

2024-12-01

Completion

2024-12-01

Countries

• United States

Study Locations