The effect of different diet modification on fat oxidation after sprint interval exercises

A single SIT session, which is known its positive effects on fat metabolism by increasing VO2 and fat oxidation and by reducing RER and carbohydrate oxidation during post-exercise period, and short-term high fat diet, which is known its positive effects on fat oxidation during pre- and post- exercise session, combination effects on fat oxidation was not studied before. The aim of the study was to investigate the effect of short-term different diet modifications (high fat and high carbohydrate) on fat oxidation after a SIT bout in healthy young trained and recreationally active men. Recreationally active (n=5, 37.8 ml.kg.min-1) and trained (n=5, 57.9 ml.kg.min-1) groups were determined according to participants' VO2max levels. It is collected individual 3-d food records, measured body composition and resting metabolic rate for calculating the daily energy requirements. Then, isocaloric 3 different diet interventions were applied with a weekly interval: normal diet, high carbohydrate diet for one day and high fat diet for three days. Before each SIT session, preprandial resting metabolic rate was measured. Participants had breakfast and following 3 hours- resting period they performed a SIT bout (6 x Wingate anaerobic sprints with a 4.5 min recovery) and immediately after 2 hour-recovery period. Mean power output (watt/kg) during sprint performances and VO2 (ml.dk-1) and RER (VCO2/VO2) which were collected from a gas analyzer for 15 min- averages during recovery period and energy derived from fat oxidation (as % and gr/min) which was calculated using established equations were compared with the groups. Resting fat oxidation rate (gr/min) was found statistically high from the other diet modifications, when the groups were disregarded. Power outputs during the SIT bouts were not differ between the diet modifications. Mean fat oxidation for last 45 min during recovery period of high fat diet in trained men were significantly different from other diet modifications and from recreationally active group. A combination of short-term high-fat diet and SIT may thought to be an alternative way of achieving weight control by increasing fat oxidation from the results of the study.