Sugar vs Carbs on Nutrition Labels For Fueling

I’ve recently started focusing a bit more on my on-the-bike fuelling strategies and have looked at how much fuel I’m taking in to see how it affects my performance. When listening to TrainerRoad podcasts and reading the forum I see the terms “sugar” and “carbs” are used fairly interchangeably. However, I’m a little confused about whether my carb targets (60g/hr, 90g/hr, etc.) should be coming specifically from sugar, or just carbs in general.

For example: I have a pile of candy in front of me where the nutritional label for a 38g serving says: “30g carbs, 0g fibre, 20g sugar”

If I have two of these 38g servings in an hour on the bike, should I count that as 60g of carbs, or just 40 since only 20 came from sugar? What if 5 of the 30g of carbs were from fibre? Do I count those as “carbs I’ve taken in on the bike” or not?

Intuitively I would think that I should only count sugars as something with “30g of carbs” and “0g of sugar” on its nutritional label doesn’t “sound” to me like it would fuel me. I apologize if this is a dumb question, but I’ve struggled to find an answer to this, and most discussions about the difference between carbs and sugars that I’ve found seem to take place in the context of keto diets which is very different from what I’m looking for.


Great question! Not dumb AT ALL.

All carbohydrates consist of sugar molecules. The type and combination of sugar molecules determine the type of carbohydrate.

There are three types of carbohydrate:

  1. Monosaccharides/ Simple sugars- consisting of single sugar molecules.
  • Glucose: The most common monosaccharide
  • Fructose: Found in fruits and honey; it is the sweetest naturally occurring sugar.
  • Galactose: Usually found in combination with glucose in lactose, the sugar in milk.
  1. Disaccharides- composed of two monosaccharide molecules linked together.
  • Sucrose: Glucose + fructose (common in table sugar)
  • Lactose: Glucose + galactose (found in milk and dairy products)
  • Maltose: 2 glucose molecules (found in malted foods and beverages)
  1. Polysaccharides/ Complex carbohydrates- composed of long chains of monosaccharide units.
  • Starch: The storage form of glucose in plants, found in foods like potatoes, rice, and bread.
  • Cellulose/ dietary fiber: A structural component of plant cell walls that we can’t digest because intestinal enzymes can’t break them down.

The 20 grams of sugar that is labeled on your candy is referring to the added sugar.

If you consume 2x 38 gram servings of your candy, you will be consuming 60 grams of carbohydrates in total.

Carbohydrates coming from dietary fiber are not going to fuel on the bike since these are not digestable.

What should you consume on the bike?
The latest science seems to suggest a mixture of glucose and fructose at a ratio of 1:0.8. The maximum amount of glucose we can absorb is around 60 grams/ hr.

Any additional carbohydrate on top of that is best coming from fructose. Most sports nutrition products should be engineered with this ratio in mind.

You can also make your own drink mix at home by buying gluocse and fructose and adding the specific quantities to your bottles.

I hope this helps! Let me know if you have questions about any of this :slight_smile: .


If you decide to make your own drink mix, this thread is very helpful


^^^ Full details in Sarah’s post above ^^^

30g carbs (10g from something, then they added 20g sugar).

Endurance energy drinks and gels are formulated to better delivery energy to your working muscles.

The carbs you might buy for endurance sports are sometimes broken down on the label into (common ingredients):

  • maltodextrose: which can be used immediately by leg muscles
  • fructose: most of these take 1-2 hours to be processed by liver before going to legs

Not all companies publish the ratio of those two ingredients.

at the high end, if you have doing a really long event and/or you have a very high FTP (at least 300W) and are doing high-intensity, you might consider going with a formula with a 1:0.8 ratio (5:4 ratio) at 120grams per hour. So if its on the label, you would see

  • 67g maltodextrose
  • 53g fructose

Table sugar is close to 50:50 ratio of glucose and fructose, so 120g of table sugar is roughly 60g glucose and 60g fructose.

Everybody is different, my body doesn’t like table sugar, and prefers the maltodextrose/fructose mixes (I make my own now).

Hope that helps.


Maybe it depends on where you live, but my understanding is that the breakdown is complex vs simple sugars, not naturally occuring vs added sugars

Like in this muesli with no added sugars. Total Carbs are complex + simple + fibers.

Complex sugars are coming from oats, and simple sugars are coming from the fruits


Here’s what the FDA says the label should mean for Total Sugars. I don’t know how up to date all labels are, whether they need to show Added Sugars. And it still doesn’t explain what the other 24 grams of carbohydrates are… my understanding is some of them can be alcohol sugars?

FDA Nutrition Facts Label

"What are Added Sugars and How are they Different from Total Sugars?

Total Sugars on the Nutrition Facts label includes sugars naturally present in many nutritious foods and beverages, such as sugar in milk and fruit as well as any added sugars that may be present in the product. No Daily Reference Value has been established for total sugars because no recommendation has been made for the total amount to eat in a day.

Added Sugars on the Nutrition Facts label include sugars that are added during the processing of foods (such as sucrose or dextrose), foods packaged as sweeteners (such as table sugar), sugars from syrups and honey, and sugars from concentrated fruit or vegetable juices. Diets high in calories from added sugars can make it difficult to meet daily recommended levels of important nutrients while staying within calorie limits.

Note: Having the word “includes” before Added Sugars on the label indicates that Added Sugars are included in the number of grams of Total Sugars in the product.

For example, a container of yogurt with added sweeteners, might list:

Total Sugars on Sample Label

This means that the product has 7 grams of Added Sugars and 8 grams of naturally occurring sugars – for a total of 15 grams of sugar."

Oh, this is in there, too for the maple syrup, fructose, maltodextrine users:
"Single-Ingredient Sugar labels

Packages and containers of products such as pure honey, pure maple syrup, or packages of pure sugar are not required to include a declaration of the number of grams of Added Sugars in a serving of the product but must still include a declaration of the percent Daily Value for Added Sugars. Manufacturers are encouraged, but not required, to use the “†” symbol immediately following the Added Sugars percent Daily Value on single-ingredient sugars, which would lead to a footnote explaining the amount of added sugars that one serving of the product contributes to the diet as well as the contribution of a serving of the product toward the percent Daily Value for Added Sugars. Single-ingredient sugars and syrups are labeled in this way so that it does not look like more sugars have been added to the product and to ensure that consumers have information about how a serving of these products contributes to the Daily Value for added sugars and to their total diet."


with respect to sugar alcohols, they must be listed one way or the other, the total sugar alcohols present can be a line in the nutritional label, but if they are added they must show in the ingredients list (erythritol, hydrogenated starch hydrolysates (HSH), isomalt, lactitol, maltitol, mannitol, sorbitol, and xylitol.) per the US FDA rules.

Also notably fiber can be digested just not by you, it get digested in the gut by micro organisms and can contribute about 2 cal/g of fiber for most fibers, it is slow release so not likely helpful as an energy source during exercise.

Finally each country has its own way of dealing with nutritional labelling and definitions are not consistent between them. The Muesli label above is likely a European label, it certainly is not a North American label. Thus the declarations may be different depending on the origin. The US FDA intent is to show the difference between the amount of added sugars vs the naturally occurring sugars in a product.

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You honestly don’t have to overthink this though the last six technical responses were fantastic.

Your candy contains 30 grams of carb so I would count that. It doesn’t matter if the carb is table sugar, fruit juice, hfc, dextrose, maltodextrin, corn syrup or whatever. It will mostly fuel you just fine minus some small differences in absorption rates.

Me, I do half Gatorade powder and half maltodextrin because it’s easy for me. I do this because I like a little orange taste but not a lot.

I don’t think one needs the perfect glucose/fructose ratio unless they are really trying to push the limits of carb/sugar intake.

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Wow, i’m pretty blown away, I definitely did not expect such a huge response from everyone. Thank you all for your incredibly in-depth and thoughtful responses!

I was primarily interested in closing my knowledge gap between what I know about “how to fuel” and “what sugars fuel you” by better understanding how nutritional labels reflect what is actually in the stuff i’m using to fuel me.

As some pointed out, in terms of being “optimal”, sport-specific fuelling products and home-made drink mixes are probably the way to go, in order to have a ratio of glucose (in some form) and fructose. Lots of great, super in-depth responses there that i’m very grateful for, and which should be really informative for anyone else who stumbles across this thread.

But sometimes you also gotta feed the soul on some of your rides which is where I rely on some “slightly” less optimal sources like candy!

From my understanding of what was said, for fuelling purposes (using North American nutritional labels) we want to count are carb/sugar intake as total carbs - (dietary fibre + sugar alcohols). Based on the reasoning that “total carbs” on nutritional labels can include fibre and sugar alcohols which don’t contribute to fuelling you while on the bike.

Let me know if i’ve missed something in my conclusion there. Otherwise, thank you all again for your responses :grinning:!

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I used to take peanut butter sandwiches on 4-5+ hour gravel rides plus sugar. They would really hit the spot at hour 3.

From a practical point of view, I don’t think you have to worry about fiber. A typical bar might only have 1 or 2 grams. A sports drink/mix isn’t going to have any fiber. Just don’t take grandma’s fiber bars on a ride. :slight_smile:

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I think some of you who make your own mixes or are simply curious how the science came together to formulate most of the ‘Endurance’ carb mixes out there will enjoy reading this blog


This is great, thanks for the link!

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Stumbled on Asker’s work/blog last year. He has a PHD in studying carbohydrate and fat metabolism during exercise. Tons of fantastic articles since he was involved behind the scenes in so much of this stuff.


The TrainerRoad community is the BEST :face_holding_back_tears:.

If you don’t need to hit 120 grams of carbs an hour (depending on your power output, duration and fueling prior to the event), the ratio of glucose to fructose becomes less important and candy can be an effective option!

Yup, exactly!

Good luck! Jump back in if you have more questions :slight_smile: .