Last updated on June 30th, 2026 at 11:02 am

Last Updated on 30th June, 2026 by Chimeremeze Emeh

Most cassava articles call it “low GI” and “diabetic-friendly.” Published clinical studies measuring real blood sugar in human volunteers found garri at 92 and fufu at 84, both firmly high GI. Here’s what the research actually says.

I have eaten cassava in nearly every form discussed in this article, boiled, fermented into garri and fufu, ground into flour, for my entire life.

So when I started researching the actual glycemic index numbers behind these foods, I was surprised by what the peer-reviewed studies actually found, since it does not match what most articles online, including an earlier version of this one, claim.

The honest answer is that most cassava-based foods test high on the glycemic index, not low or moderate as commonly stated.

This guide walks through what real clinical studies measured, food by food, so you can make informed decisions rather than rely on numbers nobody can trace to a source.

Health Disclaimer

The information in this article is for educational purposes only and does not constitute medical or dietary advice. Content on Cassava Pathway is based on published research, traditional food practices, and the author’s 30 years of hands-on cassava farming and processing experience in Eastern Nigeria. It is not a substitute for professional medical advice, diagnosis, or treatment. If you have a medical condition, are pregnant, are managing diabetes or any chronic illness, or are considering significant dietary changes, always consult a qualified healthcare provider or registered dietitian before acting on anything you read here.

What Is the Glycemic Index?

The glycemic index (GI) ranks how quickly a carbohydrate food raises blood sugar after eating, on a scale from 0 to 100, with pure glucose set at 100.

Foods with a high GI, 70 or above, cause a fast blood sugar rise. Low GI foods, 55 or below, raise blood sugar more gradually. GI values come from feeding real human volunteers a measured portion of a food and tracking their blood glucose over two hours against a glucose reference.

What Does the Research Actually Show for Cassava?

This is where most articles get cassava wrong. Multiple peer-reviewed studies measuring real blood glucose response in human volunteers found that fermented cassava products consistently test in the high GI range, above 70, not the low-to-moderate range often claimed.

One Nigerian study measuring garri, fufu, abacha, and tapioca in human volunteers found GI values of 92 for garri, 84 for fufu, 84 for abacha, and 78 for tapioca.

A separate study found similar results: garri at 92, fufu at 84. A Ghanaian study testing boiled whole cassava found a GI of 77.

Boiled cassava root specifically shows the widest range in the literature, from as low as 46 in one Kenyan study using salted cassava, up to 94±11 in international glycemic index tables.

This variation comes down to cassava variety, exact cooking method, and whether the cassava is eaten fresh or has been frozen and reheated.

The honest takeaway: cassava-based foods generally fall in the moderate to high GI range, and several of the most common preparations, garri especially, consistently test high across independent studies.

Why Cassava’s GI Varies So Much

Preparation Method Matters More Than Variety

Boiling, frying, fermenting, and drying all change how quickly cassava starch digests.

A study examining processing methods found that boiling and steaming actually increased GI in some preparations, while fermentation did not significantly lower GI the way many assume.

Frying adds fat without lowering the underlying carbohydrate impact.

Processing Level: Whole Root vs Flour or Starch

Less processed cassava generally digests more slowly than flour or starch, since processing breaks down the plant’s natural fiber structure and concentrates the available starch.

Cassava flour tends to test on the higher end of the range as a result.

Food Pairing Changes Your Actual Response

Pairing cassava with fiber, protein, or fat slows digestion and reduces the practical glycemic impact of a meal, even when the cassava itself has a high GI in isolation.

This is the single most actionable lever available to you, more so than chasing a specific preparation method.

Glycemic Index of Cassava Foods, Based on Published Research

Garri

Multiple Nigerian studies measured garri at approximately 92, placing it firmly in the high GI category.

Pairing it with vegetables or protein, the traditional way it is eaten with soup, helps offset this.

Fufu

Studies measured fufu at 84, also high GI. Eaten with a protein and vegetable-rich soup, the overall meal impact is more moderate than the isolated number suggests.

Tapioca

Measured at 78 in controlled studies, tapioca, also called cassava starch, is high GI, and sweetened dessert versions add further glycemic load from added sugar.

Abacha

Measured at 84 in the same study series, similarly high GI.

Boiled Whole Cassava Root

The most variable food in this list, with published values ranging from 46 to 94 depending on variety, salt content, and exact cooking method.

Treat any single number with caution; assume moderate to high unless you know your specific variety has been tested.

Cassava Flour

Tends toward the higher end of the range, since the milling process concentrates available starch and removes much of the fiber that would otherwise slow digestion.

Cassava Chips and Fries

Frying adds fat and calories without reducing the underlying carbohydrate impact, and these preparations are generally treated as high GI.

Is Cassava Safe for People with Diabetes?

Yes, in the same way, most high-GI staple foods can fit into a diabetic diet: through portion control, smart pairing, and attention to your individual response, not avoidance.

Choose whole, minimally processed cassava over flour or fried preparations where possible.

Pair cassava with protein, fiber, and healthy fat at the same meal.

Keep portions to roughly half a cup of cooked cassava as a starting point, and check your own blood glucose response, since published GI values come from group averages and your personal response may differ.

See our complete guide on cassava and diabetes for a deeper breakdown.

What This Means for a Low-Glycemic Diet

If you are following a low-GI eating pattern, cassava-based staples like garri, fufu, and tapioca will generally work against that goal in their traditional preparations, given how consistently they test high across independent research.

This does not mean avoiding cassava entirely. It means treating it the way you would rice, white bread, or potatoes: a food to eat in controlled portions, paired thoughtfully, rather than a food assumed to be gentle on blood sugar simply because it is a root vegetable.

Conclusion

The research on cassava’s glycemic index tells a more nuanced story than most articles suggest.

Fermented staples like garri and fufu consistently test high in controlled studies, not low or moderate as often claimed, while boiled whole cassava shows wide variation depending on preparation.

The most reliable approach is not memorizing a single number, but controlling portions, pairing cassava with protein and fiber, and monitoring your own response, since that tells you more than any published average ever will.

Frequently Asked Questions

Is cassava a high or low glycemic index?

Research shows cassava-based foods generally test moderate to high, with garri and fufu specifically measured at 92 and 84 in published studies, both in the high GI range.

Is boiled cassava better than garri for blood sugar?

Published values for boiled cassava vary widely, from 46 to 94, while garri consistently tests around 92. Boiled cassava in moderate portions is often the safer choice.

Does fermentation lower cassava’s glycemic index?

Research findings are mixed. Some studies show fermentation does not significantly lower predicted glycemic index, despite common assumptions that fermented foods like garri are gentler on blood sugar.

How much cassava can I eat if I’m watching my blood sugar?

A reasonable starting portion is about half a cup of cooked cassava, paired with protein and vegetables, adjusted based on your individual blood glucose response.