Short-Term Moderately High-Fat Diet Has No Effect on Physical Performance

Area of Science:

• Sports Nutrition
• Human Performance
• Dietary Interventions

Background:

• Military personnel and first responders have high energy demands and may face inadequate energy intake.
• Short-term high-fat diets are explored to increase energy intake, but their effect on performance is debated.
• Previous research shows conflicting results regarding short-term vs. longer-term high-fat diets on endurance performance.

Purpose of the Study:

• To investigate the impact of a 5-day moderately high-fat diet (MHF) versus a standard fat diet (SF) on physical performance.
• To compare the effects of MHF (40% fat) and SF (30% fat) diets on various physical performance metrics.
• To determine if short-term increases in dietary fat alter physical performance in healthy adults.

Main Methods:

• A randomized crossover study involving 20 healthy adults.
• Participants consumed controlled, isocaloric, protein-matched MHF and SF diets for 5 days each, with a washout period.
• Physical performance was assessed using vertical jump, 4-mile time trial, time to exhaustion, and the Army Combat Fitness Test.

Main Results:

• The MHF diet significantly increased fat intake (41% vs. 30%) and decreased carbohydrate intake (40% vs. 52%) compared to the SF diet.
• Total energy intake remained similar between the MHF and SF diet interventions.
• No significant differences were observed in any physical performance measures between the MHF and SF diet conditions.

Conclusions:

• Short-term consumption of a moderately high-fat diet does not impair physical performance.
• A 5-day MHF diet neither improved nor worsened key physical performance indicators.
• Dietary fat manipulation for short durations may not be a detrimental strategy for physical performance in active populations.