Training and Racing Behaviors of Omnivorous, Vegetarian, and Vegan Endurance Runners—Results from the NURMI Study (Step 1)

key modulator of training adaptations and racing performance, nutrition plays a critical role in endurance runners' success, and the training/racing behaviors of runners are potentially affected by their diet types. The present study aimed to investigate whether distance runners with a vegan diet (i.e., devoid of foods or ingredients from animal sources), vegetarian diet (i.e., devoid of meat and

a key modulator of training adaptations and racing performance, nutrition plays a critical role in endurance runners' success, and the training/racing behaviors of runners are potentially affected by their diet types. The present study aimed to investigate whether distance runners with a vegan diet (i.e., devoid of foods or ingredients from animal sources), vegetarian diet (i.e., devoid of meat and esh foods), and omnivorous diet (i.e., a mixed diet with no restriction on food sources) have different training and racing patterns in general and based on race distance subgroups. A total of 3835 recreational runners completed an online survey. Runners were assigned to dietary (omnivorous, vegetarian, and vegan) and race distance (<21 km, half-marathon, and marathon/ultra-marathon) groups. In addition to sociodemographic information, a complete pro le of data sets focusing on running and racing behaviors/patterns was evaluated using a questionnaire- based epidemiological approach. There were 1272 omnivores (47% females), 598 vegetarians (64% females), and 994 vegans (65% females). Compared to vegans and vegetarians, omnivorous runners prepared for a longer time period for running events, had a higher number of half-marathons and marathons completed with a better nish time, and had more reliance on training under supervision (p< 0.05). The present ndings indicate an important association of diet types with patterns of training and racing amongst endurance runners that may be related to different motives of omnivorous, vegetarian, and vegan runners for participating in events. Keywords:running; marathon; sport; race; recreational 1. Introduction Endurance running is a low-cost and convenient physical activity performed over various distances up to ultra-marathon at professional or recreational levels [1,2]. According to the International Association of Athletics Federation, endurance running popularity has increased by 60% over the past decade, and currently, more than 70,000 running events are held annually worldwide [3]. Training and competition are central components of the endurance runner lifestyle. Training and racing behaviors of endurance runners may vary Nutrients2021,13, 3521.

Nutrients2021,13, 3521 2 of 18 and relies on several intra- and inter-individual factors (e.g., runners' motives, competition level, sex, race distance, and nutrition), potentially affecting their health and performance status [4–8]. Pre-race preparation is crucial for runners' success and could be considered the most important determining factor of endurance performance. Traditionally, training for an endurance event involves a high workload in the form of long endurance runs performed the days/weeks prior to competition [5,9]. However, evidence has shown that an improper increased training load will not guarantee success and could also potentially be associated with detrimental consequences negatively affecting both performance [4] and health (e.g., running-related injuries) [10]. It has been shown that endurance athletes train and compete for approximately 1000 h per year, up to 90% of which is typically performed in different forms of low-intensity exercises [11,12]. Moreover, evidence indicates that the mean training volume of marathon runners is about 50 km/week with an average training speed of 11 km/h [9,13]. Training volume seems to have a positive association with race distance, as it has been reported that half-marathoners have fewer weekly training kilometers than marathoners [14], and the highest training mileage among distance runners is held by ultra-marathoners [15]. In addition to training type and volume, the current literature available suggests that other factors including, training intensity, training frequency (or recovery duration), duration of the training season, as well as qualitative factors related to training/racing (training supervision, nutritional supports, number of racing events, tapering phase, etc.) could be listed as remarkable parameters associated with running/racing behaviors of distance runners [4,8,16–18]. As a key modulator of training adaptations and racing performance, nutrition plays a critical role in endurance running success [19]. During the past decades, vegan (i.e., devoid of foods or ingredients from animal sources) and vegetarian diets (i.e., devoid of meat and esh foods) are increasingly followed for various reasons, including health, performance, ethical, and environmental concerns [20–23]. While the bio-availability of some nutrients has been reported to be lower in vegan/vegetarian than in mixed/Western diets [21,24], it has been well-documented that plant foods typically have higher

of foods or ingredients from animal sources) and vegetarian diets (i.e., devoid of meat and esh foods) are increasingly followed for various reasons, including health, performance, ethical, and environmental concerns [20–23]. While the bio-availability of some nutrients has been reported to be lower in vegan/vegetarian than in mixed/Western diets [21,24], it has been well-documented that plant foods typically have higher amounts of carbohydrates and antioxidants [21,25–27], bene cially affecting endurance performance [20]. According to a recent study, about 10% of marathoners follow vegan or vegetarian diets [28], and evidence indicates that the prevalence of vegan/vegetarian diets is higher among ultra- marathoners than those who run over half- or full-marathon distances [29]. However, it has been reported that there is no difference regarding diet quality scores between runners in different race distances, but vegan and vegetarian runners had higher diet quality scores than omnivorous runners [29]. Given the well-documented interconnectedness of diet types and distance running [20,29], it seems that training and racing behaviors of endurance runners could potentially be affected by their adhered diet types. To date, a large number of studies have been conducted on the concept of vegan/vegeta rian diet and endurance performance [20,30–32]. Moreover, various studies have investi- gated the pre-race preparation and/or training behaviors of endurance runners in different race distances independently [9,33,34] or comparably [8]. However, no study has examined and compared training/racing pro les of vegan, vegetarian, and omnivorous endurance runners to date. Therefore, considering the importance of nutritional demands of en- durance athletes in general, particularly of vegan/vegetarian athletes, and given the strong association between nutrition and running/racing behaviors [19], the present study was conducted to test the hypothesis whether vegan, vegetarian, and omnivorous endurance runners have different training and racing patterns. 2. Materials and Methods 2.1. Study Protocol and Ethics Approval The present investigation is a part of the Nutrition and Running High Mileage (NURMI) Study, which has been conducted in Steps 1–3 following a cross-sectional design. The study protocol of the NURMI Study [35] was approved by the ethics board of St.

Materials and Methods 2.1. Study Protocol and Ethics Approval The present investigation is a part of the Nutrition and Running High Mileage (NURMI) Study, which has been conducted in Steps 1–3 following a cross-sectional design. The study protocol of the NURMI Study [35] was approved by the ethics board of St.

Nutrients2021,13, 3521 3 of 18 Gallen, Switzerland on May 6, 2015 (EKSG 14/145) with the trial registration number ISRCTN73074080. 2.2. Participants Endurance runners were contacted and engaged mostly via social media, websites of the organizers of distance running events, running societies, email lists and runners' magazines for health, nutrition and lifestyle, trade fairs on sports, plant-based nutrition and lifestyle, and through personal contacts. Although intended to be focused on mainly Euro- pean countries, with German-speaking countries (i.e., Germany, Austria, and Switzerland) as core regions, the online investigation was spread across the globe, too, by disseminating the questionnaire of this study within the international runners' community. Therefore, a further sample of 75 highly motivated endurance runners from non-European nations provided valuable data sets by giving accurate and useable answers. To avoid forfeiting these valuable data sets and have a bigger sample size, runners who met the inclusion criteria were included in the study to increase the representation of data provided and the consequent results. The participants' sociodemographics and characteristics are presented in Table. Table 1.Sociodemographic characteristics of participants displayed by dietary subgroups.Total Omnivores Vegetarians Vegans n= 2864 n= 1272 (44%) n= 598 (21%) n= 994 (35%) Sex Female Male 1628 (57%) 1236 (43%) 600 (47%) 672 (53%) 381 (64%) 217 (36%) 647 (65%) 347 (35%) Age(years) 37 (IQR 17) 40 (IQR 17) 35 (IQR 17) 34 (IQR 15) Body Weight(kg) 66.0 (IQR 16) 68.9 (IQR 16) 63.5 (IQR 14.2) 64 (IQR 14.8) Height(m) 1.73 (IQR 0.13) 1.74 (IQR 0.12) 1.72 (IQR 0.13) 1.72 (IQR 0.14) BMICALC(kg/m 2 ) 18.50–25.00 <18.50 >25.00 2394 (83%) 138 (5%) 332 (12%) 1034 (81%) 32 (3%) 206 (16%) 518 (87%) 38 (6%) 42 (7%) 842 (85%) 68 (7%) 84 (8%) Distance Completed (total) <21 km Half-Marathon Marathon/Ultra Marathon 622 (22%) 1032 (36%) 1210 (42%) 223 (18%) 435 (34%) 614 (48%) 142 (24%) 215 (36%) 241 (40%) 257 (26%) 382 (38%) 355 (36%) Distance Completed (females) <21 km Half-Marathon Marathon/Ultra Marathon 468 (29%) 652 (40%) 508 (31%) 147 (24%) 238 (40%) 215 (36%) 113 (30%) 143 (37%) 125 (33%) 208 (32%) 271 (42%) 168 (26%) Distance Completed

Marathon/Ultra Marathon 622 (22%) 1032 (36%) 1210 (42%) 223 (18%) 435 (34%) 614 (48%) 142 (24%) 215 (36%) 241 (40%) 257 (26%) 382 (38%) 355 (36%) Distance Completed (females) <21 km Half-Marathon Marathon/Ultra Marathon 468 (29%) 652 (40%) 508 (31%) 147 (24%) 238 (40%) 215 (36%) 113 (30%) 143 (37%) 125 (33%) 208 (32%) 271 (42%) 168 (26%) Distance Completed (males) <21 km Half-Marathon Marathon/Ultra Marathon 154 (12%) 380 (31%) 702 (57%) 76 (11%) 197 (29%) 399 (60%) 29 (13%) 72 (33%) 116 (54%) 49 (14%) 111 (32%) 187 (54%) Regions/Continents Europe America Asia Other 2789 (97%) 70 (2%) 4 (<1%) 1 (<1%) 1257 (99%) 13 (1%) 2 (<1%) - 592 (99%) 6 (1%) - - 940 (95%) 51 (5%) 2 (<1%) 1 (<1%)

Nutrients2021,13, 3521 4 of 18 Table 1.Cont. Total Omnivores Vegetarians Vegans Nutrition and Fluid intake on race-day Own strategy for running races Same as training days Same as rest days/as always I eat and drink just what I feel like 1119 (39%) 917 (32%) 224 (8%) 604 (21%) 567 (45%) 361 (28%) 91 (7%) 253 (20%) 219 (37%) 199 (33%) 49 (8%) 131 (22%) 333 (34%) 357 (36%) 84 (8%) 220 (22%) Note.Results are presented as total numbers, percentage (%) and median (IQR). <21 km—less than half marathon. BMICALC—Body Mass Index calculated and categorized following the WHO guidelines [36,37]. Omnivores—have no restriction on source of food; Vegetarians—avoid all esh foods but consume egg and/or dairy products; Vegans—avoid all foods and ingredients from animal sources. 2.3. Procedures Participants completed a short, standardized questionnaire (provided in German and English) within the NURMI Study Step 1 (preliminary study, epidemiological approach) avail- able online at survey started with a written description of the procedure, and runners gave their informed consent to participate in the study. Afterward, participants completed the questionnaire, which included questions about sociodemographic characteristics, adherence to a specific diet type, the distances active in running (racing and training), and running/racing behaviors. For successful participation in the study, four inclusion criteria were applied: (1) written informed consent, (2) no less than 18 years of age, (3) questionnaire Step 1 completed retrospectively to a race, and (4) completion of an endurance running event in the past two years and still active in running (all distances, all levels). Runners who met the aforementioned inclusion criteria were enrolled in the data analysis. Participants were initially classi ed according to race distance: half-marathon and (ultra-)/marathon (data were pooled since the marathon distance is included in an ultra- marathon). The shortest and longest ultra-marathon distances reported were 50 and 160 km, respectively. Additionally, 622 highly motivated runners competing in shorter distances provided accurate answers with numerous high-quality data; however, they had not successfully participated in either a half-marathon, marathon, or ultra-marathon, but in races over distances shorter than half-marathon instead. To avoid an irreversible loss of these valuable

marathon). The shortest and longest ultra-marathon distances reported were 50 and 160 km, respectively. Additionally, 622 highly motivated runners competing in shorter distances provided accurate answers with numerous high-quality data; however, they had not successfully participated in either a half-marathon, marathon, or ultra-marathon, but in races over distances shorter than half-marathon instead. To avoid an irreversible loss of these valuable data sets, runners who met all inclusion criteria but named races shorter than half-marathon (<21 km) race as their running event were included in the study as an additional race distance subgroup. Moreover, participants were categorized into three dietary subgroups: omnivorous (commonly known as the traditional or Western diet with no restriction on any source of food), vegetarian (no meat, including no sh/shell sh, too), and vegan diets (no products from animal sources, such as meat, sh, animal fats, milk and dairy, eggs, honey, and animal byproducts) [21,38]. According to the WHO [36,37], the goal for individuals should be to maintain a BMI in the range of 18.50–24.99 kg/m 2 (BMINORM) to achieve optimum health. They point to an increased risk of co-morbidities with a BMI of 25.0–29.9 kg/m 2 and moderate to severe risk of co-morbidities with a BMI > 30 kg/m 2 [36,37]. Therefore, the calculated Body Mass Index (BMICALC) was classi ed into three categories of the body weight-to-height ratio (kg/m 2 ): 18.49 kg/m 2 < BMINORM: 18.50–24.99 kg/m 2 25 kg/m 2 . Additionally, the BMI of active runners could be below BMINORM[39], and because some people with a higher BMI might start running to achieve and maintain stable, healthy body weight, only participants with a BMI < 30 were included in the study. 2.4. Data Clearance A total number of 7422 participants took part in the survey. However, 48% dropped out, and 3835 runners completed the questionnaire. A group of 834 runners was also excluded from data analysis due to incomplete, inconsistent, and con icting data sets. Two groups of control questions were included within different sections of the questionnaire

in the survey. However, 48% dropped out, and 3835 runners completed the questionnaire. A group of 834 runners was also excluded from data analysis due to incomplete, inconsistent, and con icting data sets. Two groups of control questions were included within different sections of the questionnaire

Nutrients2021,13, 3521 5 of 18 to control for running activity and diet measures. Additionally, 156 participants without information considering running training (e.g., training time) were excluded from the study. Moreover, to control for a minimal state of health linked to a minimum level of tness [36,37] and to further enhance the reliability of data sets, the BMI approach was implemented within data clearance. Therefore, 42 runners with a BMI 30 were excluded from data analysis. After data clearance, a group of 2864 active recreational runners (including 622 runners in < 21 km, 1032 runners in half-marathon, and 1,210 runners in marathon/ultra-marathon) with complete data sets were included in nal data analysis. With regard to diet type, there were 44% (1272) omnivores, 21% (598) vegetarians, and 35% (994) vegans. As 156 runners did not report their training time, the qualitative data analysis was conducted on a group of 2708 participants. Figure of participants' enrollment in the present study.Nutrients 2021, 13, x FOR PEER REVIEW 5 of 17 start running to achieve and maintain stable, healthy body weight, only participants with 159 a BMI < 30 were included in the study. 160 2.4. Data Clearance 161 A total number of 7422 participants took part in the survey. However, 48% dropped 162 out, and 3835 runners completed the questionnaire. A group of 834 runners was also ex-163 cluded from data analysis due to incomplete, inconsistent, and conflicting data sets. Two 164 groups of control questions were included within different sections of the questionnaire 165 to control for running activity and diet measures. Additionally, 156 participants without 166 information considering running training (e.g., training time) were excluded from the 167 study. Moreover, to control for a minimal state of health linked to a minimum level of 168 fitness [36,37] and to further enhance the reliability of data sets, the BMI approach was 169 implemented within data clearance. Therefore, 42 runners with a BMI ≥ 30 were excluded 170 from data analysis. After data clearance, a group of 2864 active recreational runners (in-171 cluding 622 runners in < 21 km, 1032 runners in half-marathon, and

level of 168 fitness [36,37] and to further enhance the reliability of data sets, the BMI approach was 169 implemented within data clearance. Therefore, 42 runners with a BMI ≥ 30 were excluded 170 from data analysis. After data clearance, a group of 2864 active recreational runners (in-171 cluding 622 runners in < 21 km, 1032 runners in half-marathon, and 1,210 runners in mar-172 athon/ultra-marathon) with complete data sets were included in final data analysis. With 173 regard to diet type, there were 44% (1272) omnivores, 21% (598) vegetarians, and 35% 174 (994) vegans. As 156 runners did not report their training time, the qualitative data anal-175 ysis was conducted on a group of 2708 participants. Figure 1 shows the flow diagram of 176 participants’ enrollment in the present study. 177 178 Figure 1. Flow of participants' enrollment and dietary subgroups. Omnivores—have no restriction on source of food; Vegetarians—avoid all esh foods but consume egg and/or dairy products; Vegans—avoid all foods and ingredients from animal sources. 2.5. Measures A complete pro le of data sets focusing on running and racing behaviors/patterns was obtained using an epidemiological approach accomplished by the following items: nationality, age, sex, body weight, height, BMI, training volume (weekly/daily time of running), time to prepare for the major running event, training preparation, training super- vision, the purpose of contribution in a running race (performance vs. joyful/enjoyment

This research explores how diet influences training and racing patterns among endurance runners.