What Can I Eat With Sucrase-Isomaltase Deficiency in Australia?
If you have sucrase-isomaltase deficiency and have tried to work out what you can actually eat, you may have noticed something frustrating: the advice can be surprisingly vague.
Many commonly used CSID food lists divide foods into categories such as “most patients tolerate”, “some patients tolerate” and “few patients tolerate”. But what does that actually mean for you?
Take banana or pumpkin. You may be told that only some (or even few) people with CSID can tolerate them — but you are rarely told why. Is the problem sucrose? Starch? The variety of the food? The amount you eat? How ripe it is? Or how much residual sucrase-isomaltase activity you have?
Without knowing what sits behind the category, it is difficult to use that information to work out your own diet.
For people living in Australia, there is another problem. Many of the commonly used dietary resources for sucrase-isomaltase deficiency were developed using food composition information from the United States.
But the sucrose and starch content of foods is not necessarily identical everywhere in the world.
Different cultivars, growing conditions, production methods and food environments can all influence food composition.
A food labelled as suitable — or unsuitable — based on overseas data may therefore not accurately reflect the food you are buying and eating in Australia.
These were some of the reasons my colleagues and I conducted our recent research. Rather than developing another list based on broad categories of “tolerance”, we went back to the food composition data and asked a much more specific question:
How much sucrose and starch is actually in the foods Australians eat?
An Australian approach to a starch- and sucrose-reduced diet
In our 2026 paper published in Frontline Gastroenterology, we developed a practical framework for implementing a starch- and sucrose-reduced diet using Australian national food composition data.
We used data from AUSNUT 2023, the Australian food composition database maintained by Food Standards Australia New Zealand, and examined the sucrose and starch content of foods commonly eaten in Australia.
Importantly, we assessed sucrose and starch separately.
That matters because sucrase-isomaltase deficiency is not necessarily the same in every person. Some people may have very limited tolerance to sucrose while retaining considerably more capacity to digest starch. Others may experience symptoms with both.
Simply putting a food into a single “allowed” or “avoid” category can therefore be unnecessarily restrictive.
The aim is not to eliminate as many foods as possible.
The aim is to identify which carbohydrates need to be reduced, how much of them a food contains, and what amount of that food an individual may be able to tolerate.
First: many foods are naturally very low in sucrose and starch
When people are first told they need to reduce sucrose and starch, it can sound as though their entire diet has to change.
Fortunately, that is not the case.
Plain:
meat
chicken
fish and seafood
eggs
do not contain meaningful amounts of sucrose or starch and therefore do not require the same type of classification.
Many plain dairy foods are also naturally very low in sucrose and starch. However, lactose is a separate carbohydrate and may need to be considered if you also have lactose intolerance. Flavoured dairy foods and processed products can also contain added sucrose or starch, so ingredient lists still matter.
The foods that require more careful consideration are the major carbohydrate-containing food groups, including:
fruit
vegetables
legumes
nuts and seeds
grains
bread and cereal products
rice and pasta
potatoes and other starchy vegetables
foods containing added sucrose
These were therefore the food groups we focused on when developing the Australian framework.
Why country-specific food information matters
One of the most interesting findings from our research was just how much an overseas food list can change when Australian food composition data are used.
Pumpkin is a good example.
Pumpkin is commonly restricted on overseas starch- and sucrose-reduced food lists. However, our analysis found that Australian Kent and Jarrahdale pumpkin varieties were low in both sucrose and starch.
We also identified foods commonly eaten in Australia, including broccolini, golden honeydew melon and lychee, that met our low-sucrose and low-starch criteria but were absent from commonly used overseas lists.
Even foods that people may assume are very high in sucrose can be surprising. Grapes and figs, for example, met the low-sucrose threshold in the Australian dataset.
This does not necessarily mean that an overseas food list is “wrong”.
It means that where the food data came from matters.
And if dietary advice is going to be used in Australia, it makes sense to look at Australian foods.
So how did we classify the foods?
We used quantitative thresholds rather than simply labelling foods according to general impressions of tolerance.
For both sucrose and starch, foods were classified using a simple traffic-light system:
🟢 Low: ≤1 g per 100 g
🟡 Moderate: >1 to ≤2 g per 100 g
🔴 Higher: >2 g per 100 g
Sucrose and starch were assessed independently.
That last point is particularly important.
A food can be low in sucrose but high in starch.
Or it can contain more sucrose while containing almost no starch.
Knowing both values allows the diet to be adjusted to the individual's digestive capacity rather than automatically excluding the food.
Foods low in both sucrose and starch
Using Australian food composition data, we identified 27 fruit varieties and 43 vegetable varieties containing:
≤1 g sucrose AND ≤1 g starch per 100 g.
These foods are consistent with foods typically included without strict portion restriction in starch- and sucrose-reduced dietary protocols.
Table 1. Australian fruit meeting low-sucrose and low-starch criteria
Blackberry | Papaya, Pawpaw |
Blueberry | Pear, green, Packham, William Bartlett, canned |
Cherry | Pear, Nashi |
Currant, fresh | Persimmon |
Fig | Pomegranate |
Grapes, all | Prickly Pear |
Guava | Quince |
Honey dew melon, yellow skin | Raisin |
Kiwifruit, green, gold | Raspberry, fresh, frozen |
Lemon | Rhubarb |
Lime (including native lime) | Salted plum |
Loquat | Strawberries, fresh, frozen |
Lychee, fresh | Wax jambu |
Mulberry |
|
Table 2. Australian vegetables meeting low-sucrose and low-starch criteria
Artichoke, globe, canned hearts | Melon, Bitter |
Asparagus | Melon, Hairy |
Bamboo shoot | Mushrooms, common |
Bean, green | Olives |
Bok choy, choy sum | Onion, white |
Broccoli | Pumpkin, Kent, Jarrahdale |
Broccolini | Radish, red skinned, white skinned |
Cabbage, Chinese, Napa, mustard, red, savoy, white | Rocket |
Capsicum, green, red, yellow | Seaweed |
Cauliflower | Shallot |
Celery | Silver beet |
Chicory | Spinach, baby, English |
Chilli, green, red | Spring onion |
Choko | Sprouts, alfalfa |
Cucumber, common, Lebanese, telegraph | Sprouts, bean |
Eggplant | Squash, button, scallopini |
Endive | Swede |
Fennel | Tomato, common, cherry, Roma, canned |
Kale | Turnip |
Kohlrabi | Watercress |
Leek | Zucchini, green skin, golden |
Lettuce, cos, iceberg, mignonette, mixed leafy greens |
|
This list is considerably broader than many people expect when they first start looking at a starch- and sucrose-reduced diet.
It includes foods such as berries, cherries, grapes, kiwifruit, pears, broccoli, capsicum, eggplant, leafy greens, tomatoes, zucchini and Australian Kent and Jarrahdale pumpkin.
But note, food composition is only one part of tolerance. The amount eaten at one sitting, the total carbohydrate load across a meal or day, individual enzyme activity and other gastrointestinal sensitivities can all influence symptoms.
A food doesn't always need to be completely excluded
There is another important limitation to the way food lists are commonly presented.
Food composition data are generally expressed per 100 g, and some CSID dietary protocols also classify foods according to how much sucrose or starch they contain per 100 g.
That is useful for comparing foods — but it does not necessarily reflect how we actually eat them.
When was the last time you ate 100 g of garlic?
Garlic is a perfect example of why per-100 g values need to be interpreted in the context of the amount actually eaten. Garlic appears in the “few CSID patients tolerate” category on some overseas food lists. But most people are not eating anything close to 100 g of garlic at a meal.
A typical garlic clove weighs only around 3 g. Using Australian food composition values, that amount provides only about 0.1 g of sucrose and essentially no starch — well below the 1 g portion thresholds used in this guide.
So looking only at the amount of sucrose or starch per 100 g can make a food appear much more problematic than the amount actually eaten would suggest.
The same principle applies in the opposite direction. A food that looks relatively low per 100 g could still provide a substantial sucrose or starch load if a very large portion is eaten.
The amount you actually eat matters.
This is why, in our study, we did not stop at classifying foods according to their sucrose and starch content per 100 g.
For foods containing more than 1 g sucrose per 100 g, we asked a much more practical question:
How much of this food would provide approximately 1 g of sucrose while keeping starch at or below 1 g?
That produced some surprisingly useful results.
Take apples.
A Fuji apple falls outside the lowest sucrose category when assessed per 100 g and apples are commonly placed in the “few CSID patients tolerate” category on overseas food lists.
But approximately half a medium Fuji apple provides around 1 g of sucrose while remaining low in starch.
So rather than simply saying:
“You can't eat apples.”
a more useful question is:
“What amount of apple provides a defined sucrose load — and is that amount tolerated by this particular person?”
This is the difference between using food composition data to create a blanket exclusion list and using those same data to guide real-world portions.
And you don't need to calculate these portions yourself. The full Australian dataset (link below) includes calculated portion amounts for foods above the low thresholds, showing the amount corresponding to approximately 1 g of sucrose or 1 g of starch, depending on which carbohydrate is limiting. You can use these amounts as a starting point for exploring your own individual tolerance.
Want to see what this looks like in practice? Table 3 gives some examples for commonly eaten Australian fruit and vegetables.
Table 3. Portion guidance for selected higher-sucrose Australian fruit and vegetables: portions providing approximately 1 g sucrose while keeping starch ≤1 g
Food | Standard serve (g) | Calculated portion corresponding to 1 g sucrose (g) |
Fruit | ||
Apple, Fuji, unpeeled | 150 g (1 medium) | ½ medium apple |
Mango, peeled | 150 g | 1 tbsp diced |
Orange, peeled | 150 g (1 medium) | ¼ medium orange |
Peach, yellow, unpeeled | 150 g (1 medium) | ⅛ medium peach |
Pineapple, peeled | 150 g | ⅛ cup diced |
Watermelon, peeled | 150 g | ¼ cup diced |
Vegetables | ||
Beetroot, fresh, baked | 75 g | 1–2 thin slices |
Carrot, fresh, raw | 75 g | ¼ cup chopped |
Pumpkin, fresh, baked | 75 g | 3 tbsp cooked |
Nuts and seeds: portions can add up quickly
Nuts and seeds are nutritious foods, but they are another good example of why a starch- and sucrose-reduced diet shouldn't simply be divided into foods you “can” and “can't” eat.
Many nuts contain relatively little sucrose in a normal eating portion, but the amount can add up quickly if portions become large. This is particularly relevant because it is very easy to eat considerably more than one handful when snacking. In addition, many CSID recipes online use substantial amounts of nut or coconut flour, which can result in a substantially larger sucrose load than eating a typical portion of whole nuts.
For many nuts, the amount providing approximately 1 g of sucrose is around a small handful, although the exact amount varies by nut. By contrast, some seeds and seed products are naturally much lower in sucrose. Chia seeds and tahini, for example, contain approximately 0.7 g sucrose per 100 g.
Table 4. Portion guidance for nuts and seeds
Nut / Seed | Sucrose per 100g | Calculated amount providing ~1 g sucrose |
Almonds | 4.6g | 21g |
Almond meal/flour | 3.9g | 25g |
Brazil nuts | 2.1g | 47g |
Cashews | 5.5g | 18g |
Chia seeds | 0.7g | 140g |
Coconut, dessicated | 5.5g | 18g |
Flaxseeds (linseeds) | 1.5g | 65g |
Hazelnuts | 4.4g | 22g |
Macadamia nuts | 4.5g | 22g |
Peanuts | 5.1g | 19g |
Pecans | 4.3g | 23g |
Pine nuts | 3.4g | 29g |
Pistachio | 5.9g | 17g |
Pumpkin seeds | 1.3g | 75g |
Sesame seeds (tahini) | 0.7g | 140g |
Sunflower seeds | 2.1g | 47g |
Walnuts | 2.7g | 37g |
A useful rule of thumb: weigh your usual handful once. For many nuts, a small handful is close to the calculated amount providing approximately 1 g of sucrose, although the amount varies considerably between nuts.
What about fibre?
Fibre is another issue I think deserves much more attention when implementing a starch- and sucrose-reduced diet.
Previous dietary intervention studies of a starch and sucrose reduce diet have reported fibre intakes of only around 15–18 g per day.
That is not an inevitable consequence of reducing sucrose and starch. It is more likely to happen when someone is given a long exclusion list without enough guidance about what to eat instead.
In our study, we therefore specifically looked for fibre-rich foods that could still fit within the starch- and sucrose-reduced framework.
Table 5. Fibre-dense foods that provide ≤1 g sucrose and ≤1 g starch per serve
Fibre Source | Standard serve (g) | Fibre per standard serve (g) |
Fruit | ||
Blueberry, raw | 150 | 4.5 |
Blackberry, raw | 150 | 7 |
Currants, fresh | 150 | 6.4 |
Date, dried* | 30 | 3 |
Fig, dried* | 30 | 4.3 |
Pear, William Bartlett, raw | 150 | 5.5 |
Pomegranate, peeled, raw | 150 | 10 |
Raspberry, raw | 150 | 7.2 |
Vegetables | ||
Artichoke, globe, boiled, drained | 75 | 7 |
Broccoli, fresh, baked, no added fat | 75 | 3.2 |
Eggplant, skin on, roasted | 75 | 3.4 |
Kale, fried, no added fat | 75 | 5.6 |
Seeds | ||
Chia seed, dried† | 15 | 5 |
Flaxseed/linseed** dried† | 15 | 5 |
Psyllium, uncooked† | 5 | 4.5 |
Tahini (sesame seed paste) | 30 | 4 |
* Dried fruits listed contain <2g starch per 100g and were included where a standard serve provides ≤1g sucrose and ≤1g starch.
** Flaxseed/linseed contains 1.5g sucrose per 100 g but provides ≤1g sucrose per defined portion.
†For seeds and seed-based products, a 15 g portion was applied in place of the 30 g Australian Dietary Guidelines serve as a pragmatic clinical quantity, reflecting gastrointestinal tolerance considerations, particularly for linseeds and chia, where smaller amounts are often initially introduced . Psyllium is reported using a 5g defined portion consistent with typical starting doses used in practice to minimise gastrointestinal side effects during fibre introduction.
The table includes foods such as berries, pomegranate, artichoke, broccoli, eggplant, kale, chia seeds, linseeds, psyllium and tahini.
Our three-day dietary modelling showed that fibre intakes within recommended ranges can be achieved on a starch- and sucrose-reduced diet when compatible fibre-rich foods are deliberately included.
This is important because managing gastrointestinal symptoms should not come at the expense of long-term dietary quality.
Want to look up the actual food data?
One thing that was particularly important to me when developing this work was transparency.
I don't think people should simply be handed a list and expected to accept that a food belongs in an “allowed” or “avoid” category without being able to see the data behind that decision.
For that reason, the complete Australian dataset used in our study is freely available through the Bond University research repository.
The full dataset also includes the traffic-light classifications for both sucrose and starch, so you can quickly see whether a food falls into the low, moderate or higher category.
It includes the sucrose, maltose, starch and dietary fibre values for Australian fruits, vegetables, nuts, seeds and legumes, along with commonly consumed grains and non-grain starches.
View the Australian SSRD dataset:https://research.bond.edu.au/en/datasets/ssrd-dataset-australia/
You can also read the full peer-reviewed paper here:
English CJ, Mueller K, Radd-Vagenas S. Practical framework for implementing a starch- and sucrose-reduced diet using Australian national food composition data. Frontline Gastroenterology. 2026.
The tables are a starting point — not the whole diet
There is one very important limitation to any food list, including the tables above:
Food composition data tell us what is in the food. They do not tell us exactly how much you can digest.
Sucrase-isomaltase deficiency exists across a spectrum.
Some people appear to retain considerable starch-digesting capacity but tolerate very little sucrose.
Others need to reduce both sucrose and starch much more substantially.
Tolerance may also be influenced by:
the amount eaten at one sitting
the total sucrose and starch load across a meal
the total load across the day
ripeness and preparation of the food
an individual's residual enzyme activity
other gastrointestinal conditions or food intolerances
There can also be overlap with FODMAP sensitivity. A food may be very low in both sucrose and starch and still cause symptoms in someone who reacts to a particular FODMAP.
This is why the goal of dietary treatment should not be to remain indefinitely on the smallest possible list of foods.
The goal is to use the available evidence as a starting point, determine your individual tolerance to sucrose and starch, and then build the most varied and nutritionally adequate diet possible around that tolerance.
Getting help with sucrase-isomaltase deficiency
Implementing a starch- and sucrose-reduced diet is best done with a health professional who understands sucrase-isomaltase deficiency and can help distinguish between sucrose intolerance, starch intolerance and other overlapping gastrointestinal triggers.
This is a particular area of my clinical and research work.
I work via telehealth with adults throughout Australia who have diagnosed or suspected sucrase-isomaltase deficiency. My approach is to use the Australian food composition data as the foundation, then individualise the diet according to symptoms, food tolerance, nutritional requirements and lifestyle.
If you would like help implementing the diet, you can book a consultation here.
The information in this article is general in nature and is not intended to replace individual medical or nutritional advice.
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