Do Larger Athletes Need More Carbs During Exercise? A Research Deep Dive
Carbohydrates are a cornerstone of endurance nutrition, fueling sustained energy and performance during workouts and races. But are traditional guidelines like “60–90 grams of carbs per hour” sufficient for everyone? New research suggests that body size plays a significant role in athletes’ capacity to metabolize carbohydrates during exercise, and larger athletes may require higher intake rates to meet their energy demands.
Let’s dive into the findings from a groundbreaking study published in the International Journal of Sport Nutrition and Exercise Metabolism and explore how this research could reshape fueling strategies for athletes of all sizes.
The Study in a Nutshell
In a 2024 study by Ijaz et al., researchers investigated the relationship between body size and exogenous glucose oxidation (the ability to use ingested carbohydrates as fuel during exercise).
Study Details:
Participants: 15 trained cyclists were divided into two groups based on body size:
Small group (<70 kg)
Large group (>70 kg)
Protocol: Cyclists completed a two-hour cycling session at 95% of their lactate threshold while consuming 90 grams of carbohydrates per hour.
Measurement: The researchers assessed how much of the ingested glucose was oxidized (used as energy) during exercise.
Key Findings:
Larger athletes oxidized significantly more exogenous glucose than their smaller peers:
Small group: ~33 grams/hour
Large group: ~45 grams/hour
Body size was positively correlated with the ability to oxidize ingested carbohydrates, suggesting that traditional carbohydrate guidelines may not be sufficient for larger athletes.
NOTE: Separating athletes into groups by body size is not meant to harm body image or create negative associations. Instead, these groupings are often used to analyze data more effectively and explore how different variables might influence performance, health, or outcomes.
Body weight is influenced by many factors, including genetics, muscle mass, hydration status, and bone density, as well as environmental and lifestyle factors. It is not a sole indicator of health or ability. Every body is unique, and the diversity in weight and composition reflects the wide variety of ways bodies adapt and thrive in different contexts. Check out this blog for more guidance on navigating body image.
Why The Results of this Study Matter
The study challenges the “one-size-fits-all” approach to carbohydrate fueling during exercise, which typically recommends 60–90 grams per hour for endurance athletes. For larger individuals, these standardized guidelines may fall short, leaving them underfueled and at risk of suboptimal performance.
🔑 Key Takeaways from the Research
Body Size Influences Carb Oxidation
Larger athletes demonstrated a higher capacity to oxidize exogenous glucose, meaning they can process and utilize more of the carbs they consume during exercise.Tailored Carb Intake is Crucial
The researchers proposed that carbohydrate intake should be individualized based on body size, with a target of approximately 0.7 grams of carbs per kilogram of body weight per hour.
For a 70 kg athlete: ~49 grams/hour
For an 85 kg athlete: ~60 grams/hour
This personalized approach ensures athletes meet their energy demands and avoid running out of fuel during training or competition.
Traditional Guidelines May Underserve Larger Athletes
Current recommendations of 60–90 grams per hour may not adequately support the energy needs of larger athletes, potentially leading to fatigue or decreased performance.Performance Benefits of Optimized Fueling
By adjusting carb intake to match individual oxidation rates, athletes can sustain energy levels, maintain intensity, and optimize endurance performance.
Practical Applications for Athletes
This research highlights the importance of tailoring fueling strategies to an athlete’s unique physiology. Here’s how you can apply these findings to your training and competition plans:
1. Calculate Your Personalized Carb Needs
Use the guideline of 0.7 grams of carbs per kilogram of body weight per hour as a starting point.
Example: If you weigh 80 kg, aim for at least ~56 grams of carbs per hour during endurance workouts.
2. Experiment During Training
Practice your fueling strategy in training sessions to identify the optimal amount of carbs that your body can tolerate and utilize. Gradually increase intake if you’re not meeting your target.
3. Choose Easily Digestible Carbs
Opt for carb sources that are fast-absorbing and easy on your stomach, such as:
Sports drinks or powders
Energy gels or chews
Bananas or dates
4. Monitor Your Performance
Pay attention to your energy levels, endurance, and recovery. Adjust your carb intake based on how your body responds.
5. Work with a Sports Dietitian
A registered dietitian who specializes in sports nutrition (hi!) can help you fine-tune your fueling plan based on your individual needs, training volume, and goals.
Real-World Implications for Sports Nutrition Guidelines
The findings from this study call for a shift in how sports nutrition guidelines are developed and applied. Instead of relying on generalized recommendations, practitioners and athletes should consider factors like body size, energy expenditure, and individual metabolism when creating fueling plans.
Key Implications:
Larger athletes should prioritize higher carbohydrate intake during prolonged exercise to match their increased oxidation capacity.
Sports nutrition products and education should emphasize flexible guidelines that accommodate a range of body sizes and needs.
Beyond the Study: Addressing Individual Variability
While body size is a significant factor in carbohydrate oxidation, other variables like fitness level, training intensity, and gut tolerance also play a role. Athletes should adopt a holistic approach to nutrition, considering both research-based guidelines and their personal experiences.
Conclusion: Fuel Smarter, Perform Better
This research reinforces the importance of individualized fueling strategies for athletes. By aligning carbohydrate intake with your body size and energy demands, you can optimize performance, prevent fatigue, and recover more effectively.
Whether you’re a recreational cyclist or an elite endurance athlete, tailoring your nutrition plan to your unique physiology is a game-changer.
Need help crafting a personalized fueling strategy?
Let’s work together to create a plan that supports your training and competition goals. Book a Fueling & Strategy Session today, and take the first step toward unlocking your full athletic potential.
Reference:
Ijaz, A., Collins, A. J., Moreno-Cabañas, A., Bradshaw, L., Hutchins, K., Betts, J. A., Podlogar, T., Wallis, G. A., & Gonzalez, J. T. (2024). Exogenous Glucose Oxidation During Exercise Is Positively Related to Body Size. International Journal of Sport Nutrition and Exercise Metabolism, 1–12. Advance online publication. https://doi.org/10.1123/ijsnem.2024-0097