385 after exercise, and 30 min after completion of exercise. Blood levels of estradiol, progesterone, glucose, and free fatty acid (FFA) were assessed. The duration of each menstrual cycle phase was estimated by assessing the levels of the estradiol and progesterone. RESULTS: The menstrual cycle of the subjects was 30.9±1.9 days. MP was 4.1±1.4 days, and LP was 24.8 ± 2.2 days. Blood concentrations of estradiol (MP, rest, 35±14.6 pg/mL; LP, rest, 164±58.3 pg/mL, p<0.001) and progesterone (MP, rest, 0.3±0.2 ng/mL; LP, rest, 13.1±5.0 ng/mL, p<0.001) were significantly higher in LP than in MP. No significant differences were observed in the levels of glucose (p=0.36), FFA (p=0.80), and respiratory exchange ratio (p=0.34) at all time points. Carbohydrate oxidation (MP, 38.5±7.7 g; LP, 39.2±6.4 g, p=0.66), fat oxidation (MP, 11.6±2.9 g; LP, 11.2±3.4 g, p=0.64), and exercise time to exhaustion were not different between MP and LP (MP, 7.4±7.9 min; LP, 6.8±6.0 min, p=0.55). CONCLUSION: Our results reveal no effect of the menstrual cycle phase on substrate oxidation and prolonged endurance exercise performance during cycle ergometer exercise in eumenorrheic women. 1423 Board #185 May 30 10:30 AM - 12:00 PM A Short-term Calorie Restricted Diet with High-fat on Inflammatory Biomarkers and Plasma Lipids Yunsuk Koh. Baylor University, Waco, TX. Email: yunsuk_koh@baylor.edu (No relationships reported) A high-fat (HF) diet may play a positive role in weight management and body composition, yet its role in inflammation and blood lipids is not clearly understood. PURPOSE:To examinethe effects of a short-term calorie restricted diet with HF or high-carbohydrate (HC) and an acute bout of exercise on plasma lipids and inflammatory biomarkers. METHODS: In a randomized, cross-over design, 9 physically inactive college-aged individuals were assigned to a calorie restricted diet (20% reduction of total calorie intake from their typical diet) with either HF or HC for 2 weeks. The HF diet consisted of 70% fat (mostly mono- and poly-unsaturated fatty acids) and 30% carbohydrate and protein, whereas the HC diet consisted of 70% carbohydrate and 30% fat and protein. There was a one-week wash-out period between the two diet interventions. At the end of each diet intervention, a single bout of aerobic exercise was performed at 70% heart rate reserve for 40 minutes. Overnight fasting blood samples were collected at pre- and 24-hours post-exercise at the end of each diet intervention (pre- intervention, HF, and HC) to analyze changes in the key biomarkers of inflammation and plasma lipids, including glucose and triglycerides. RESULTS: Either HF or HC diet did not change any inflammatory biomarkers or plasma lipids. However, a single bout of exercise significantly decreased B-cell activating factor (BAFF, 1619.37±446.57 to 1520.94±476.05 pg/mL, p=0.019), matrix metalloproteinase-3 (MMP-3, 1700.82±1090.16 to 1227.33±976.38 pg/mL, p=0.021), thymic stromal lymphopoietin (TSLP, 2.38±1.4 to 1.88±1.0 pg/mL, p=0.048), and TNF-related weak inducer of apoptosis (TWEAK, 26.26±10.36 to 22.53±3.0 pg/mL, p=0.048). CONCLUSION:A short-term calorie restricted diet with either HF or HC may not significantly influence soluble inflammatory markers or plasma lipids. However, a single bout of aerobic exercise, independent of dietary modification, can improve inflammatory responses in healthy, sedentary young adults. Future studies need to further examine the effects of a long-term diet intervention on the responses of inflammatory markers in a variety of subject populations, including obese and patients with metabolic diseases in order to better understand the role of high-fat diet in inflammation. 1424 Board #186 May 30 10:30 AM - 12:00 PM Impact of Time Restricted Feeding on Muscular Strength Within a Healthy Adult Population. Eric A. Norman, Nicole L. Schweitzer, Corbyn R. Bendtsen, Megan M. Coyle, Cassie A. Fileccia, Marquel A. Fleischacker, Lauren M. Kaminski, Andrew L. Kezar, Megan M. Lind, Emma P. Masiulewicz, Justin R. Geijer. Winona State University, Winona, MN. (No relationships reported) Time restricted feeding (TRF) is a feeding habit that restricts the amount of time during the day in which individuals consume calories. TRF has been shown to produce several health benefits, one of which may be an increase in force production. Muscular strength and nutritional intake have been strongly researched prior to this study. Though little research exists investigating the impacts of TRF on muscular strength in human subjects. PURPOSE: The purpose of this study was to identify the potential impacts of TRF on muscular strength. METHODS: Participants participated in two, four-week periods during which caloric intake, sleep duration, sleep quality, exercise, and medications were all documented. The first period, participants partook in non-TRF eating behavior. The second period participants were exposed to a nine-hour window of TRF. To measure muscular strength, participants were tested using an isokinetic dynamometer. Resting metabolism was also measured. Statistical analyses quantifying within subject effects were performed with a repeated measures ANOVA. Post-hoc analyses were performed to elicit differences between testing periods. RESULTS: Both mean torque flexion at 60 degrees/second (MTF 60) (83.92 Nm ± 29.53Nm vs. 95.63 Nm ± 28.95 Nm) and mean torque flexion at 180 degrees/second (MTF 180) (66.75 Nm ± 25.9 Nm vs. 69.01 Nm ± 21.29 Nm vs. 75.55 Nm ± 23.9 Nm; F = 7.920 Nm) had a significant increase from pre-test to TRF, as well as non-TRF to TRF. Post-hoc testing revealed significant differences between pre-test and TRF MTF 60 increased (p-value=0.001). Similar results were found for MTF 180 as well (p-value=0.037). When observing respiratory quotient (RQ) at rest (0.716±0.077 vs. 0.73 ±0.077 vs. 0.08±0.79; F = 8.352) there was a significant increase from pre-test to TRF (p-value=0.008), as well as non-TRF to TRF (p-value=0.034). Lastly, after analyzing total strength training days from non-TRF to TRF (8.11 days ± 1.18 vs. 5.22 days ± 1.48), a significant decrease was found (p-value=0.003). CONCLUSION: Post TRF, participants showed an increase in muscular strength and resting RQ despite a decrease in strength training. Increased glucose utilization may be linked to short bouts of increased muscular strength activity. Future studies are needed to identify physiological mechanisms behind these findings. 1425 Board #187 May 30 10:30 AM - 12:00 PM Effects Of Whole30 Dietary Programa On Resting Energy Expenditure, Oxygen Consumption And Heart Rate In Crossfit Athletes Valden Capistrano Junior 1 , Renata Carnauba 2 , Natália Marques 2 , Ana Beatriz Baptistella 2 , Renata Sena 3 , Angela Furtado Martin 1 , Adriana Sampaio 1 , Diego Lacerda 3 . 1 VClinica de Nutrição, Fortaleza, Brazil. 2 Centro de Nutrição Funcional VP, São Paulo, Brazil. 3 CrossFit Haka, Fortaleza, Brazil. Email: valdenjunior@gmail.com (No relationships reported) Valden L. M. Capistrano Junior, Renata A. Carnauba, Natália Marques, Ana Beatriz Baptistella, Renata Desiree Beserra de Sena, Angela Siqueira Furtado Martin, Adriana Pereira Sampaio, Diego de Castro e Silva Lacerda. VClínica de Nutrição Research Institute PURPOSE: To evaluate whether the Whole 30 dietary program alters resting energy expenditure, oxygen consumption, and heart rate in CrossFit trained individuals. METHODS: Sixty four subjects (age range: 21-54 years) attended to nutrition education class to learn food items and recommended volumes comprising the Whole 30 program for 30 days (allowed foods: meats, seafood/ fish, eggs, fruit, vegetables and mono and polyunsaturated fats; forbidden foods: sugar, sweeteners, alcohol, flour, oat, quinoa, corn, rice, starch, beans, soy, milk and dairy products) and underwent a underwent a training protocol (4dyas/week) during the program period. Resting energy expenditure and oxygen consumption were evaluated before the beginning and one day after the end of protocol by indirect calorimetry (CardioCoach, Korr™), and the resting heart rate by oximeter finger. Samples were tested for normal distribution and groups were compared by Student's t-test. The type 1 error was set at p<0.05. RESULTS: Of the 64 initial participants, 38 participants who had no follow-up information were excluded and final analysis was performed in 26 (40.63%) participants. There was a significant reduction in resting energy expenditure (1402±255.7 vs 1087±303.3, pre and post, respectively, p=0.00001), resting oxygen consumption (203.6±36.91 vs 154.3±35.58, pre and post, respectively, p=0.0001) and resting heart rate (59.58±15.32 vs 51.46±13.73, pre and post, respectively, p=0.0001). CONCLUSION: The Whole 30 dietary program promoted resting energy expenditure, oxygen consumption and heart rate reduction in trained Crossfit individuals, which may be related to the lower carbohydrate consumption proposed by the program. Copyright © 2019 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.