If you’re an endurance athlete with diabetes or prediabetes, you’ve probably picked up a bar labeled “low sugar” thinking it would help you keep blood sugars stable during training.
But here’s the uncomfortable truth:
Most low-sugar or “zero sugar added” bars contain sugar alcohols — and sugar alcohols are one of the TOP causes of stomach issues in runners, cyclists, and triathletes.
They can cause:
- gas
- bloating
- cramping
- nausea
- diarrhea
- urgent bathroom stops mid-run
And for athletes managing diabetes, sugar alcohols can still affect blood glucose, contribute carbohydrates, and make fueling unpredictable.
This post explains exactly why sugar alcohols don’t belong in an endurance athlete’s fueling plan — and what to choose instead.
What Are Sugar Alcohols?
Sugar alcohols are sweeteners used to reduce sugar on labels. You’ll commonly see:
- erythritol
- xylitol
- sorbitol
- maltitol
- mannitol
- isomalt
They are most commonly found in:
- “low sugar” protein bars
- “zero sugar” snacks
- sugar-free candy
- many meal-replacement bars
- baked goods marketed as “diabetes friendly”
Examples of Bars to Avoid
Barebells Protein Bars – These contain maltitol, a sugar alcohol known for GI distress, gas, and delayed glucose rises. Barebells bars are not good choices for endurance athletes with diabetes.
Other examples include bars from:
- ONE Bar (some flavors)
- Quest (many contain erythritol)
- Atkins bars
- Many keto bars
If a bar uses sugar alcohols, it’s almost always a sign it’s not ideal for training.
Why Sugar Alcohols Cause GI Distress in Endurance Athletes
1. They’re poorly absorbed in the gut
Sugar alcohols sit in the intestines pulling water into the colon → bloating, cramping, or diarrhea. During endurance exercise, reduced gut blood flow makes this effect even worse.
2. They ferment in the colon
Your gut bacteria ferment sugar alcohols, producing gas and pressure. Running + fermentation = bathroom emergency waiting to happen.
3. They worsen normal exercise-related GI issues
Endurance athletes already struggle with:
- dehydration
- jostling of the gut
- reduced blood flow to the stomach
- higher cortisol
Add sugar alcohols → doubling the digestive stress.
This is why you never see sugar alcohols in real sports nutrition products like Skratch, Maurten, Huma, GU, or Tailwind.
Why Sugar Alcohols Are Misleading for Athletes With Diabetes & Prediabetes
1. Sugar alcohols STILL contain carbohydrates
Many athletes incorrectly believe that “low sugar” = better blood sugars.
Not true. Sugar alcohols show up in the “Total Carbohydrate” section of the nutrition facts panel, even if the marketing claims “zero sugar.”
Maltitol, found in Barebells bars, behaves almost like regular sugar and can increase blood sugar.
2. They cause delayed, unpredictable glucose responses
Some athletes spike 1–2 hours later rather than right away. This makes training, racing, and insulin adjustments harder.
3. They trick athletes into under-fueling
Endurance athletes NEED carbs to avoid:
- early fatigue
- bonking
- post-exercise lows
- higher cortisol
- poor recovery
A bar with sugar alcohols may be low sugar — but it’s also low usable energy.
How to Spot Sugar Alcohols on Labels
Check the ingredients for:
- “sugar alcohols” under carbohydrates
- anything ending in -ol
- maltitol (most common in bars)
- erythritol
- “low net carbs” (marketing red flag)
If you see maltitol, erythritol, or xylitol, put it back.
Better Bar Options for Endurance Athletes With Diabetes
These options use real carbs (glucose, fruit sugars, oats, honey) that digest cleanly and predictably.
Sports Nutrition Bars (Ideal for Training)
- Skratch Anytime Bar
- Picky Bars
- Huma Bars
- Clif Bars
- Honey Stinger Waffles
Whole-Food Based Bars
- Larabar
- That’s It Bars
- RX Bar (for pre-workout, not mid-run)
These work with your gut and your glucose — not against it.
FAQs
1. Are sugar alcohols bad for runners?
Yes. Sugar alcohols are poorly absorbed and easily cause gas, bloating, stomach cramps, and diarrhea — which are amplified during running due to reduced gut blood flow.
2. Do sugar alcohols raise blood sugar in athletes with diabetes?
Some do. Maltitol (found in Barebells bars) can cause glucose rises similar to sugar. Others may cause delayed or unpredictable blood sugar responses.
3. Are Barebells bars good for athletes with diabetes?
No. Barebells bars contain maltitol, a sugar alcohol known for causing significant GI distress and delayed glucose increases. They are not ideal for endurance fueling.
4. Should endurance athletes avoid low-sugar or no-sugar bars?
Yes — if the bar contains sugar alcohols. Endurance athletes need predictable carbohydrates for fuel. Sugar alcohols do not provide usable energy and can cause stomach issues that ruin a workout.
5. What bars are best for endurance athletes with diabetes?
Bars with real carbohydrates: Skratch, Huma, Picky Bars, Larabar, Honey Stinger, That’s It, and Clif Bars depending on timing.
Conclusion
Sugar alcohols look appealing on labels — especially for athletes trying to manage blood sugars — but they are one of the biggest GI triggers for endurance athletes.
They:
- cause bloating, gas, cramps, and diarrhea
- still contribute carbs
- can raise or delay blood sugars
- make fueling unpredictable
- provide poor usable energy
For athletes with diabetes or prediabetes, predictable carb sources matter. Sugar alcohols simply don’t support performance, gut health, or glucose control.
Ready to Fuel Your Training Without GI Issues or Blood Sugar Surprises?
I help endurance athletes with diabetes and prediabetes create fueling plans that support stable glucose, better energy, and stronger performance — without stomach drama.
Book your 1:1 Endurance Fueling Assessment here.
Download my free guide: Top 10 Snacks for Endurance Athletes With Diabetes.
