If you’re an endurance athlete with prediabetes, you’ve probably heard conflicting advice:
- “Cut carbs and your blood sugar will improve.”
- “Eat low carb to prevent glucose spikes.”
- “Carbs will make you fat and slow your recovery.”
Here’s the surprising truth: Cutting carbs too aggressively can hurt performance, recovery, and even glucose control.
In this post, we’ll break down:
- Why low-carb strategies can backfire for athletes with prediabetes
- How to fuel smartly for training and races
- The types and timing of carbs that support glucose stability
- Simple action steps you can start today
If you want individualized guidance for carb timing, training performance, and blood sugar control, book a 1:1 session with me today!
Why Low-Carb Can Be Harmful for Endurance Athletes With Prediabetes
1. Reduced Training Performance
Carbs are the primary fuel for high-intensity efforts. Restricting them can cause:
- Early fatigue during workouts
- Reduced training quality
- Poor race performance
2. Worsened Insulin Sensitivity
Underfueling increases cortisol, which makes blood sugar more unpredictable — even on rest days.
3. Increased Risk of Hypoglycemia
Low-carb athletes with prediabetes may experience:
- Mid-run lows
- Weakness and shakiness
- Slower recovery
How Much Carb Do Endurance Athletes With Prediabetes Really Need?
| Training Type | Carb Intake (g/kg body weight) | Notes |
| Easy Zone 2 | 3–5 | Supports energy, recovery, steady glucose |
| Moderate / Tempo | 5–7 | Fuels longer sessions, prevents bonking |
| Long / Intense | 6–10 | Needed for endurance performance |
Tip: Always combine carbs with protein/fiber to slow glucose absorption.
Best Carb Sources for Athletes With Prediabetes
- Oats, rice, quinoa
- Fruit (bananas, berries, apples)
- Sweet potatoes
- Whole-grain bread or wraps
- Sports gels and drinks during workouts
Avoid sugar alcohol-heavy bars (like Barebells) during training — they can cause GI distress and unpredictable glucose rises.
Carb Timing for Blood Sugar Stability
Before Workouts
- 30–60 minutes prior: small carb + protein snack
- Example: banana + peanut butter
During Long Sessions
- 20–40g carbs per hour for workouts >60 minutes
Post-Workout (within 30 minutes)
- 40–60g carbs + 20–30g protein to replenish glycogen and support insulin sensitivity
Let me help you optimize carbs around your workouts to stabilize blood sugars and improve performance. Schedule your 1:1 session now!
Why “Low-Carb” Labels Can Be Misleading
- Many bars marketed as “low-carb” contain sugar alcohols (e.g., Barebells bars)
- Sugar alcohols = GI distress + still count toward total carbs
- Net carbs can mislead athletes into underfueling
Common Mistakes Endurance Athletes Make With Carbs
- Cutting carbs too aggressively
- Skipping post-workout fueling
- Using sugar alcohol-heavy bars during training
- Believing fasting runs are always better
FAQ – Carbs & Prediabetes for Endurance Athletes
1. Can I go low-carb and still train?
Yes, but performance may suffer, and glucose control can worsen if underfueling causes stress and cortisol spikes.
2. What about sugar-free or low-carb bars?
Many contain sugar alcohols (like Barebells bars), which cause GI distress and unpredictable blood sugar.
3. How do I know how many carbs I need?
It depends on training intensity, duration, and your glucose trends. Using a CGM or tracking performance helps fine-tune intake.
4. Can carbs really help with blood sugar control?
Yes! When timed strategically around workouts, carbs improve insulin sensitivity, stabilize glucose, and support recovery.
Conclusion
Cutting carbs isn’t a one-size-fits-all solution for endurance athletes with prediabetes. The key is strategic carb intake, timing, and quality to:
- Support performance
- Improve insulin sensitivity
- Avoid hypoglycemia
- Maintain recovery
Book your personalized 1:1 fueling session and learn exactly how to balance carbs, performance, and glucose control for your training. Plus, download my Top 10 Snacks for Endurance Athletes With Diabetes & Prediabetes to use during training.
