None listed
Conditions
Brief summary
The widespread availability of heavily processed, energy-dense foods, combined with increasingly inactive lifestyles, is contributing to growing rates of obesity and related health conditions across Western societies. These foods, typically high in fat, sugar, and artificial ingredients, have been linked to a range of adverse health outcomes, including poor blood sugar regulation, liver dysfunction, and increased levels of lipids in the blood, such as elevated triglycerides. These effects appear to occur regardless of total calorie intake, suggesting that the quality of one's diet plays an important and independent role in overall health. Regular physical activity remains one of the most effective non-pharmacological strategies for counteracting the negative health consequences of a prolonged poor diet. Engagement in structured exercise is associated with improvements in cardiovascular and cardiorespiratory fitness, which is among the strongest known indicators of long-term health outcomes and reduced risk of premature mortality, as well as beneficial effects on blood lipid levels. Despite this, the majority of the general population continue to fall short of recommended physical activity guidelines. Endurance athletes are a unique population that demonstrate exceptional cardiovascular fitness but also possess improved blood sugar regulation and more favourable blood lipid profiles compared to the general population. Highly trained triathletes typically accumulate > 14 hours of training/week and expend considerable amounts of energy daily. The physiological adaptations resulting from this level of training are known to support many of the same biological processes that are disrupted by a diet high in ultra-processed foods (UPF). What remains unclear, however, is whether these adaptations are sufficient to protect metabolic health during consumption of an UPF diet. Therefore, this study aims to determine whether highly trained endurance athletes are able to offset the associated negative metabolic health consequences of an UPF diet. We hypothesise that highly trained endurance athletes will: (1) be protected against UPF-associated suppression of HDL-cholesterol, in contrast to previously reported findings in healthy, active populations; (2) endurance athletes will be protected against UPF-associated elevations in blood pressure and heart rate variability depression relative to their habitual diet (HAB); and (3) experience no significant changes in fat mass or body composition.
Interventions
20 male and female endurance-based athletes (triathletes and cyclists; training > 12 h/week), aged 18-45 years, will be recruited for this single-arm study design. All participants will complete a normal habitual diet period (28 days) before then competing an ultra-processed food (UPF) diet (28 days). Screening and pre-testing (Visit 1) for the study will include; blood lipid screen, blood pressure, Exercise & Sports Science Australia (ESSA) Adult Pre-Exercise Screening Tool (APSS) and a ramp pr
20 male and female endurance-based athletes (triathletes and cyclists; training > 12 h/week), aged 18-45 years, will be recruited for this single-arm study design. All participants will complete a normal habitual diet period (28 days) before then competing an ultra-processed food (UPF) diet (28 days). Screening and pre-testing (Visit 1) for the study will include; blood lipid screen, blood pressure, Exercise & Sports Science Australia (ESSA) Adult Pre-Exercise Screening Tool (APSS) and a ramp protocol test for the determination of maximal oxygen uptake (VO2max). On the morning of Visit 2 (baseline testing), participants will arrive at the Australian Catholic University (ACU) Melbourne campus following an overnight fast to complete a dual X-ray absorptiometry (DXA) scan to assess body composition, provide a blood sample (~21 mL; see outcome measures below), undertake blood pressure measures, and complete three questionnaires; Recovery-Stress Questionnaire for Athletes (RESTQ-Sport); Pittsburgh Sleep Quality Index (PSQI) and Gastrointestinal Symptom Rating Scale (GSRS). Following the completion of these surveys, participants will undergo a mixed meal tolerance test (MMTT), consisting of the consumption of a mixed meal of a known nutritional composition, followed by repeated blood samples (~42 mL total) for 2 h post ingestion to determine insulin sensitivity and whole-body glucose handling. Following this, participants will complete a maximal fat oxidation exercise test (FATmax). Upon completion of baseline testing, participants will consume their habitual diet in free-living conditions (i.e., ad libitum without dietary restrictions) for 28 d. Participants will be asked to provide photo logs of all food and fluid intake during the 28 d habitual diet period using a commercial mobile phone app (e.g. Cronometer) that will be programmed to share data with the research team while hiding real time feedback from the user. Energy and macronutrient intake will be assessed by a team of registered dietitians with the aid of AI recognition of food photos. On Day 14 (Visit 3), participants will report to the laboratory and provide a blood sample (~21 mL) and undergo blood pressure measurement before completing the questionnaires (RESTQ-Sport, GSRS and PSQI). Following the 28-d habitual diet period (Day 29, Visit 6), participants will report to the lab after an overnight fast and repeat the DXA scan, provide a blood sample (~21 mL), undertake blood pressure measures, an MMTT, complete a battery of questionnaires (PSQI, RESTQ-SPORT and GSRS) followed by a FATmax. Immediately, following Visit 4, all participants will then complete 28 d of a UPF diet. Participants will be required to consumed three meals (breakfast, lunch, dinner) each day and food items must be selected from the McDonald’s food and drink menu (ad libitum until satiety). Participants will be supplied with unique login details to the McDonalds app in order for the research team to track what was purchased. Participants will also be requested to photograph any food items that were not consumed which will be sent to the research team via WhatsApp text message. Additional UPF snacks (e.g., gummy sweets, energy bars, energy gels) will be provided during the UPF dietary condition to aid intra and between-workout fueling. Dietary compliance will be defined as exclusive adherence to the designated menu on a minimum of 6 out of 7 days per week for the 4-week dietary intervention. Participants will be required to attend the ACU laboratory at the same timepoints (Visit 5 on day 14, Visit 6 on day 29) for follow-up testing as outlined above. Throughout the entire intervention period, regular ‘check-ins’ via text message will be used to assess compliance with diet and exercise training. Diet tracking and food provisions will be managed by qualified clinical dietitian. Participants will be asked to maintain their current training regime and to record daily exercise training (via the TrainingPeaks app).
16 male and female endurance-based athletes (triathletes and cyclists; training > 12 h/week), aged 18-45 years, will be recruited for this single-arm study design. All participants will complete a normal habitual diet period (28 days) before then competing an ultra-processed food (UPF) diet (28 days). Screening and pre-testing (Visit 1) for the study will include; blood lipid screen, blood pressure, Exercise & Sports Science Australia (ESSA) Adult Pre-Exercise Screening Tool (APSS), Eating Disor
16 male and female endurance-based athletes (triathletes and cyclists; training > 12 h/week), aged 18-45 years, will be recruited for this single-arm study design. All participants will complete a normal habitual diet period (28 days) before then competing an ultra-processed food (UPF) diet (28 days). Screening and pre-testing (Visit 1) for the study will include; blood lipid screen, blood pressure, Exercise & Sports Science Australia (ESSA) Adult Pre-Exercise Screening Tool (APSS), Eating Disorder Examination Questionnaire, a brief dietitian interview, and a ramp protocol test for the determination of maximal oxygen uptake (VO2max). On the morning of Visit 2 (baseline testing), participants will arrive at the Australian Catholic University (ACU) Melbourne campus following an overnight fast to complete a dual X-ray absorptiometry (DXA) scan to assess body composition, provide a blood sample (~21 mL; see outcome measures below), undertake blood pressure measures, and complete three questionnaires; Recovery-Stress Questionnaire for Athletes (RESTQ-Sport); Pittsburgh Sleep Quality Index (PSQI) and Gastrointestinal Symptom Rating Scale (GSRS). Following the completion of these surveys, participants will complete a maximal fat oxidation exercise test (FATmax). Following this, participants will undergo a mixed meal tolerance test (MMTT), consisting of the consumption of a mixed meal of a known nutritional composition, followed by repeated blood samples (~42 mL total) for 2 h post ingestion to determine insulin sensitivity and whole-body glucose handling. Upon completion of baseline testing, participants will consume their habitual diet in free-living conditions (i.e., ad libitum without dietary restrictions) for 28 d. Participants will be asked to provide photo logs of all food and fluid intake during the 28 d habitual diet period using a commercial mobile phone app (Cronometer) that will be programmed to share data with the research team while hiding real time feedback from the user. Energy and macronutrient intake will be assessed by a registered dietitian with the aid of AI recognition of food photos. On Day 14 (Visit 3), participants will report to the laboratory and provide a blood sample (~21 mL) and undergo blood pressure measurement before completing the questionnaires (RESTQ-Sport, GSRS and PSQI). Following the 28-d habitual diet period (Day 29, Visit 6), participants will report to the lab after an overnight fast and repeat the DXA scan, provide a blood sample (~21 mL), undertake blood pressure measures, an MMTT, complete a battery of questionnaires (PSQI, RESTQ-SPORT, and GSRS) followed by a FATmax. Immediately, following Visit 4, all participants will then complete 28 d of a UPF diet. Participants will be required to consumed three meals (breakfast, lunch, dinner) each day and food items must be selected from the McDonald’s or KFC food and drink menu (ad libitum until satiety). Participants will be supplied with unique login details to the McDonalds and KFC app in order for the research team to track what was purchased. Participants will also be requested to photograph any food items that were not consumed which will be uploaded onto Cronometer. Additional UPF snacks (e.g., gummy sweets, energy bars, energy gels) will be provided during the UPF dietary condition to aid intra and between-workout fueling and recorded on Cronometer. Dietary compliance will be defined as exclusive adherence to the designated menu on a minimum of 6 out of 7 days per week for the 4-week dietary intervention. Participants will be required to attend the ACU laboratory at the same timepoints (Visit 5 on day 14, Visit 6 on day 29) for follow-up testing as outlined above. Throughout the entire intervention period, weekly health check-ins via text message will be used to assess compliance with diet and exercise training. Diet tracking and food provisions will be managed by qualified clinical dietitian. Participants will be asked to maintain their current training regime and to record daily exercise training (via the TrainingPeaks app). Participants will also wear an Oura Ring throughout the 8-week trial to assess heart rate variability.
Sponsors
Australian Catholic University, Mary Makillop Institure for Health Research.
Study design
Allocation
Non-randomised trial
Intervention model
Single group
Primary purpose
Prevention
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 45 Years
Healthy volunteers
No
Inclusion criteria
Participants will be recruited if they meet the following criteria: • Healthy • Aged 18-45 years • Competitive athletes training > 12 h/week • Ironman (3.8 km swim, 180 km bike, 42.2 km run) personal best times of < 11 h (males) and < 12 h (females).
Exclusion criteria
• Current musculoskeletal injuries that prevent you from training. • Current/historical/family history of cardiovascular disease. • Hypertension (>140/90 mmHg). • Eating disorders/disordered eating. • Regular alcohol (> 14 and > 7 standard drinks/week for males and females, respectively) / smoking use. • Pregnant or breast feeding. • Lipid-lowering, anti-hyperglycemic and incretin mimetic medication use.
Outcome results
None listed