The purpose of this study is to look at how fast commercially available supplements containing carbohydrate can get into the bloodstream. If carbohydrate, in the form of glucose, gets into the blood faster, this can provide an instant energy source and help fuel the body during exercise. We will be testing three supplements, namely Voom Pocket Rocket, SIS Go Isotonic Energy Gel, and Maurten Gel 160. Each participant will complete all three conditions, consuming one of each supplement at random per condition. The study requires participation from male runners, cyclists and triathletes who are aged between 18-35.

Each visit will take approximately 1 hour and 30 minutes, and three experimental visits per participant. The study will involve frequent blood sampling and the continuous monitoring of gas exchange (oxygen/carbon dioxide). Blood sampling via cannulation will be used to analyse the lactate, glucose, and insulin content of the blood. Gas exchange will measure the oxygen breathed in and carbon dioxide breathed out throughout the study.

The investigators plan to carry out the study on 16 participants who will be a mix of male runners, cyclists and triathletes.

The aim of this study is to investigate and compare the speed of delivery of three commercially available carbohydrate supplements during a 1 hour modified glucose tolerance test. This study will be a randomised double-blind crossover in design. Participants will be required to attend the Human Performance Laboratory at Lancaster University on three separate visits. During each visit, participants will be required to consume one of three commercially available carbohydrate supplements, namely Maurten Gel 160 (MAU), Voom Pocket Rocket Electro Energy Bar (PR), and SIS Go Isotonic Energy Gel (SIS). Each consumable will be blinded to both the researchers and participants, flavoured the same (lemon and lime) and placed into identical packaging with anonymised labelling to minimise the risk of bias. The supplements will be matched for carbohydrate content (45 grams). Blinding of supplements will be completed offsite by people not in the research team and followed strict food and hygiene protocols. Each participant will complete all three conditions, consuming one of each supplement at random per condition.

Each visit will involve frequent venous blood sampling for glucose, lactate and insulin. An anterograde venous cannula will be inserted into a vein in the antecubital fossa of the arm by a qualified member of the research team. This is a less invasive alternative to an arterial cannula whilst still allowing for accurate metabolic measures to be taken. This method is also less painful than inserting a retrograde cannula which can cause significant discomfort.

Once the anterograde venous cannula is inserted and secured in place, a resting measurement of blood will be taken (1ml of blood taken to measure glucose and lactate, and 3ml for insulin). Participants will then be required to consume one of the three carbohydrate energy supplements. Once the supplement had been consumed, continuous gas analysis will begin to analyse gas exchange to non-invasively measure substrate utilisation. This signals the start of the test, and a timer will be set for 1 hour.

Throughout the test, blood sampling will be taken in frequent intervals. 1ml of blood sampled every 5 minutes to check for glucose and lactate, and 3ml of blood sampled every 10 minutes for insulin. Gas exchange will be continuously measured to non-invasively measure substrate utilization in the muscle via indirect calorimetry which determines energy expenditure by measuring the body's oxygen consumption and carbon dioxide production. The measurement is based on the assumption that the volume of oxygen (VO2) consumed is used to oxidise fuels, and the volume of carbon dioxide (VCO2) produced is a by-product of substrate utilisation.

After the study visit, analysis will be conducted assessing how each of the three supplements effect blood glucose, blood lactate, insulin, and gas exchange.

Inclusion Criteria:

• Aged between 18-35 years
• Males
• Tier 2 runners, cyclists, and triathletes; local level representation, training ~ 3 times per week, training with a purpose to compete, identify with a specific sport, limited skill development
• BMI between 18.5-24.9 - based on healthy weight range for BMI as per NHS and BMI of recreational to elite long-distance runners

Exclusion Criteria:

• Allergies to any listed ingredients on any supplements.
• Diabetes (type 1 or 2)
• Any medical conditions
• Smokers
• Anyone using drugs or medication
• Anyone consuming alcohol within 24 hours of the study
• Exercise must be restricted within 24 hours of the study
• Caffeine must not be consumed within 24 hours of testing as it can significantly enhance carbohydrate oxidation rates
• Diets including high-carbohydrate-low-fat (HCLF), low-carbohydrate-high-fat (LCHF), ketogenic, and/or glycogen manipulation diets

Only biological males are eligible to participate in this study.

It was decided that a male only cohort would be included in this study due to the timeframe of the research (undertaken as part of a Masters by Research degree), and that including females would require a larger sample size, and thus a longer timeframe. Research has also found sex differences between responses to glucose absorption, demonstrating that females have a slower glucose absorption time, and that the menstrual cycle can significantly effect glucose absorption which would lengthen the time of research as a greater sample size would be needed with strict controls on contraception & tracking of menstrual cycle.

Both the participants and investigators will be blinded to what supplement they are consuming on each visit. Each supplement will taste the same, and be placed into identical packaging, and be randomly labelled (e.g., A, B, C). This will be done to avoid potential bias.