Why is white sugar low in FODMAP?: Decoding Sucrose for Gut Health

October 13, 2025 •

3 min read

According to Monash University, the creators of the low FODMAP diet, standard white table sugar contains no FODMAPs. This can be a surprising fact for many managing conditions like Irritable Bowel Syndrome (IBS). Understanding why is white sugar low in FODMAP comes down to its specific molecular structure and how the body processes its components.

Quick Summary

White table sugar, or sucrose, is considered low FODMAP because it is composed of equal parts glucose and fructose. This balanced ratio allows the body to efficiently absorb the fructose, preventing fermentation in the gut that can trigger IBS symptoms.

Key Points

Balanced Ratio: White sugar contains a 1:1 ratio of glucose and fructose, which allows for efficient absorption.
No Excess Fructose: The key issue with high FODMAP sweeteners is excess fructose, which white sugar does not contain.
Glucose's Role: The presence of glucose helps the small intestine absorb the fructose component effectively.
Not Fructans: Unlike other sweeteners like coconut sugar or inulin, white sugar does not contain high levels of fructans.
Low FODMAP ≠ Free Pass: Despite being low FODMAP, general health guidelines advise consuming all sugars in moderation.
Not All Sugars are the Same: Many other sweeteners, such as agave and honey, are high FODMAP and should be avoided during the elimination phase.
Variations Tolerated: Finely milled white sugars like powdered or caster sugar are also low FODMAP.

What are FODMAPs?

Before delving into white sugar, it's essential to understand the basics of FODMAPs. The acronym stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. These are short-chain carbohydrates found in many everyday foods that are poorly absorbed by some individuals. For those with sensitive digestive systems, such as people with IBS, these poorly absorbed carbohydrates can travel to the large intestine where gut bacteria ferment them. This process creates gas, drawing water into the bowel and causing symptoms like bloating, pain, and altered bowel habits.

The Key FODMAP Categories

Oligosaccharides: Fructans (found in wheat, onion, garlic) and GOS (found in legumes).
Disaccharides: Lactose (found in dairy).
Monosaccharides: Excess fructose (found in honey, apples, high-fructose corn syrup).
Polyols: Sugar alcohols like sorbitol and mannitol (found in some fruits and artificial sweeteners).

The Science of Sucrose: Why White Sugar Is Different

White table sugar, chemically known as sucrose, is a disaccharide made up of one glucose molecule bonded to one fructose molecule. While the 'D' in FODMAP stands for disaccharides, sucrose doesn't fall into the high FODMAP category like lactose does. This is due to the balanced ratio of its components.

Why Excess Fructose is the Real Culprit

For a food to be considered high FODMAP due to its fructose content, it must contain excess fructose, meaning there is more fructose than glucose. White sugar, with its perfect 1:1 ratio, does not have this issue. The presence of glucose helps the body absorb the fructose more efficiently in the small intestine, preventing it from continuing to the large intestine where it can cause fermentation and symptoms.

High FODMAP Sweeteners to Avoid

To highlight why white sugar is different, it's useful to look at sweeteners that are high in FODMAPs and should be avoided or limited during the elimination phase of the diet:

Agave Nectar: Contains a much higher concentration of fructose than glucose, making it a major excess fructose offender.
Honey: Also contains excess fructose, making it high FODMAP in larger servings.
High Fructose Corn Syrup (HFCS): As the name suggests, HFCS has an unfavorable fructose-to-glucose ratio.
Coconut Sugar: High in fructans, particularly in servings larger than one teaspoon.
Sugar Alcohols (Polyols): Sorbitol, mannitol, and xylitol are poorly absorbed and can cause significant digestive distress.

A Quick Comparison: Low vs. High FODMAP Sweeteners


Sweetener	FODMAP Status	Key Reason
White Sugar (Sucrose)	Low	Balanced 1:1 glucose to fructose ratio allows for proper absorption.
Brown Sugar	Low	Similar to white sugar, with added molasses that doesn't affect FODMAP status in moderation.
Maple Syrup	Low	Safe in recommended serving sizes; does not contain excess fructose.
Rice Malt Syrup	Low	Fructose-free and generally well-tolerated.
Agave Nectar	High	Contains high levels of excess fructose, which can be poorly absorbed.
Honey	High	Features excess fructose, especially in larger quantities.
Sorbitol	High	A sugar alcohol (polyol) that is poorly absorbed and highly fermentable.
Inulin	High	A type of fructan (oligosaccharide) that acts as a prebiotic and is poorly digested.

Moderation is Still Key for Overall Health

While white sugar is low FODMAP, it is not a health food and offers no nutritional value beyond calories. A low FODMAP designation simply means it is less likely to trigger IBS symptoms in sensitive individuals. It is crucial to consume it in moderation as part of a balanced diet, following general healthy eating guidelines. Relying heavily on any added sugar, regardless of its FODMAP status, is not recommended for overall wellness.

Conclusion: Making Informed Choices

For those following a low FODMAP diet, understanding the nuances of sweeteners like sucrose is vital for diversifying their meals without triggering digestive symptoms. The key to why is white sugar low in FODMAP lies in its equal proportion of glucose and fructose, which facilitates proper absorption in the small intestine. This prevents the fermentation that occurs with excess fructose and other high FODMAP carbohydrates. When managed correctly, this information allows individuals to navigate the diet with greater freedom and confidence, enabling them to make informed choices about the sweeteners they consume.

It is always best to consult the latest research and guidelines from authoritative sources like Monash University. For more information, you can reference the Monash University FODMAP Diet App.

Frequently Asked Questions

While considered low FODMAP because it contains no excess fructose, general healthy eating advice recommends moderate consumption. The low FODMAP status relates specifically to digestive fermentation, not overall healthiness.

Table sugar (sucrose) is a molecule of both glucose and fructose bonded together in equal parts. The FODMAP issue arises from excess fructose, which table sugar does not have. Pure fructose is high FODMAP because it is poorly absorbed without an equal amount of glucose.

Yes, brown sugar is also low FODMAP. It is refined white sugar with molasses added and, like white sugar, does not contain excess fructose. The molasses content is not a FODMAP issue.

Other low FODMAP sweeteners include pure maple syrup and rice malt syrup in recommended serving sizes, as well as dextrose and pure glucose.

Most sugar alcohols (polyols), such as sorbitol and mannitol, are high FODMAP and should be avoided. They are poorly absorbed and highly fermentable, triggering digestive symptoms.

Honey is high FODMAP because it naturally contains more fructose than glucose, resulting in excess fructose. This excess can be poorly absorbed and fermented by gut bacteria, causing symptoms in sensitive individuals.

While lab tests show even large quantities of white sugar are low FODMAP, general guidelines still suggest moderate intake for overall health. The amount tolerated varies, but its low FODMAP status means it's less likely to cause gut distress than high FODMAP alternatives.