Many studies have been conducted over the years examining the effects of reducing dietary carbohydrates on health and physical performance. This study analyzed the effects of altering diets from “the usual Western diet (WD) to a high-fat very low-carbohydrate (VLCHF) diet for 4 weeks” on performance and physiological responses during interval training high intensity (HIIT). Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay To conduct the study, 18 moderately trained males were examined over the course of 4 weeks. They were divided into two groups: 1. A high fat, very low carbohydrate group and 2. A usual mixed Western diet group. A VLCHF diet limited carbohydrate consumption to 20-50 g/day and replaced most lost calories with fat and maintained a low to moderate amount of protein. Males were aged between 18 and 30 years and engaged in regular non-competitive, low-resistance physical activity of at least 3 sessions per week, and all participants had no experience with the VLCHF diet. A maximal incremental treadmill test (GXT) was performed before and after the experiment to identify VO2 max. The treadmill started at 7.0 km/h and increased by 1.5 km/h every 4 minutes. The HIIT sessions were conducted across the 4 weeks and the sessions were separated by 48 hours. These sessions involved warming up for 10 minutes at 60% of VO2 max. The main session consisted of 5 very intense 3-minute repetitions at 100% VO2 max. Recovery was 90 seconds. The HIIT sessions lasted 34 minutes. The sessions were conducted in the morning at the same time every day (30 minutes more or less) at least 3 hours after the last meal. The tests were conducted in a thermally controlled environment where body mass composition was determined and a capillary blood sample was taken prior to all exercise interventions. Participants were also asked to participate in 3-5 sessions of primarily resistance-based, unsupervised training, as well as recording their heart rate during these sessions. Participants were provided with meal planning recipes and tips from dietitians, and assistance was provided during the test when requested by participants. Starting 5 days before surgery, all quantities of food consumed were recorded daily. Alcohol consumption before and during the intervention was prohibited as was caffeine consumption before the laboratory sessions. The results showed that overall there were no negative effects on the GTX or HIIT performance of participants consuming the VLCHF diet. In the VLCHF group, substrate oxidation was also found to change significantly. Fat oxidation levels and blood lactate concentrations increased in the VLCHF diet group. The results of this study call into question the supposed necessity of a high-carbohydrate diet for high-intensity exercise. Some research suggests that it may take several weeks for noticeable adaptations to occur with the VLCHF diet. One study that recorded the results of relative power during a 6-second sprint improved after 12 weeks of adapting to the VLCHF diet. The short time period in which the study was conducted is a limitation of this study as it does not give participants the opportunity to adapt.