Effects Of High Fat Diet (24-hour) On Ventilatory Threshold And Time To Exhaustion In Females

Abstract

Prior to competition, athletes ingest meals mixed in content from high carbohydrate to high fat and/or high protein. Ingestion of specific meal content prior to exertion is varied and often confusing. PURPOSE The purpose of this study was to analyze the effect of two varying highfat content meals on the ventilatory threshold (VT), time to exhaustion (TTE), rating of perceived exertion (RPE) and respiratory exchange ratio (RER). METHODS Subjects were twelve (12) physically active females mean age 21.5 (y), weight 59.1 (kg) and VO2max of 37.3 (ml*kg−1*min.−1). All testing was approved by University Internal Review Board committee, and all subjects signed an informed consent prior to testing. Two treatments, high-fat (HF) and normal-fat diet (NF), were randomly assigned. The VT was determined by the V-slope method. Fat content for treatments consisted of ∼31% (NF) and ∼54.9% (HF) respectively. Normal fat intake was determined utilizing a three-day food journal. The HF diet was averaged from two meals ranging from 39.7% to 58.6% fat. Post-testing was done within 7 hours post absorption for both treatments. Descriptive statistics (mean ± SD) were used to determine subject demographics. Variance between treatments and post meal measures were analyzed with a Repeated Measures ANOVA. Significance was set at p ≤ 0.05. RESULTS Results indicate no significant difference between the following measures: VT for the HF (1.82±.64, L/min) vs. NF diet (1.61±.34, L/min); TTE between the HF diet (11.18±2.36, min) vs. NF diet (11.22±2.64, min); RPE at volitional fatigue for NF diet (17.1±1.2) vs. HF diet (17.1±2.1); and RER for NF diet (1.2±0.096) vs. HF diet (1.1±0.062). CONCLUSIONS Ventilatory threshold was not significantly influenced by alteration of ingested fat content prior to exertion. Additionally, HF vs. NF diets did not alter time to exhaustion, RPE or RER. The current data does not explain previously reported significant decreases of performance measures associated with a 24-hour high fat diet and is justification for additional study.