GSID Dietary Restrictions

Choosing Your Foods

A basic diet guide for people with GSID

Every case of GSID is unique, so no one diet works for all. Patients with GSID will need to work with their physician and a registered dietitian (RD) to develop an individualized diet to meet their specific needs. In general, dietary treatment for GSID is focused on sugar (sucrose) and starch (isomaltose and maltose) restrictions. The degree of restriction is patient-specific.

Keeping food logs or food diaries is an important part of planning the diet. All foods and beverages consumed should be recorded. The food log should include the time the food was consumed, what food was consumed, details about the food and how it was prepared, and how much food was consumed (i.e., 1/2 cup, 8 ounces, 2 tablespoons). Symptoms, such as bloating, gas, diarrhea, or abdominal pain, should also be recorded. The time when the symptom started, and the length of time the symptom lasted should be recorded. A food and symptom log will help the RD plan an appropriate diet that will meet the specific needs of that patient.

It is typically recommended that the majority of sucrose and starch be eliminated from the diet initially. This is called an elimination diet. However, the elimination diet may not be nutritionally complete and should not be followed for more than approximately two weeks.

Sucrose, a carbohydrate known as “table sugar” or “white sugar,” is added to many processed foods. Sucrose also occurs naturally in some foods, such as fruits and juices. Most GSID patients have a problem with sucrose digestion. After the initial two-week elimination diet is completed, sucrose-containing foods are gradually added back to the diet to determine how much sucrose can be tolerated. It is recommended that only one new food be re-introduced into the diet every three to five days before adding the next new food.

Starch, along with fiber and sugars, are other types of carbohydrates. Starch is found in grains (wheat, oats, rice, etc.) and starchy vegetables (corn, potatoes, beans, peas, lentils, etc.). Breads, cereals, and crackers, including gluten-free breads, cereals and crackers are high in starch. Certain ingredients such as maltodextrin, a modified tapioca starch, are other sources of starch. After the two-week elimination period, it is important to determine starch tolerance by re-introducing starch containing foods gradually (one new food every three to five days). It is also important to continue keeping a food and symptom log during this time. Disaccharidase results (a test that determines how much enzyme activity exists in the small intestine), if available, may be used as an initial indication of general starch tolerance.

Below is a table to assist patients, physicians, and RDs in planning both the elimination diet (low-sucrose, low-starch) and the re-introduction of foods as sucrose and starch tolerance is established. The fruits and vegetables in the “foods tolerated by most” column are the foods allowed during the two-week elimination phase of the diet (low-sucrose, low-starch). The foods in the other two columns are then gradually re-introduced into the diet to determine sucrose and starch tolerance.

Fruits Tolerated by Most GSID Patients Fruits Tolerated by Some GSID Patients Fruits Tolerated by Few GSID Patients
cranberries, fresh
figs, raw
cantaloupe (rockmelon)
honeydew melon
passion fruit
tangerines (mandarin oranges, clementines)
Vegetables & Legumes Tolerated by Most GSID Patients Vegetables & Legumes Tolerated by Some GSID Patients Vegetables & Legumes Tolerated by Few GSID Patients
alfafa sprouts
*artichoke, globe
bamboo shoots
bok choy
*brussel sprouts
collard greens
green beans
mung bean sprouts
mustard greens
peppers (red, yellow, and green)
spaghetti squash
yellow squash (summer)
zucchini (courgette)
edamame soybeans
snow peas
yellow wax beans
black beans
black-eyed peas (cowpeas)
butternut/buttercup squash
cassava (yuca)
chickpeas (garbanzo beans)
green peas
kidney beans
lima beans
navy beans
pinto beans
split peas
sweet potatoes

*It should be noted that artichokes, asparagus, broccoli, brussels sprouts, cabbage, and cauliflower can cause gas in all individuals, not just patients with GSID, so consumption of these should be monitored closely.


Choosing carbohydrates that are higher in fiber, which slows down the rate of digestion, may be better tolerated than the more processed carbohydrates. For example, choose whole-grain bread instead of white bread, whole grain breakfast cereals (made with whole oats, barley, or bran) instead of more processed cereals, and choose whole-wheat pasta, quinoa, lentils, brown rice, or wild rice instead of processed grains like white rice. It is important to read food labels carefully because some whole-grain products may have added sugars including sucrose.

Since the digestion of starch begins in the mouth with salivary amylase (a digestive enzyme), it is important to thoroughly chew starchy foods. The more the food is chewed, the greater the exposure the starch has to the enzyme to allow for more starch to be broken down and digested.

Adding fat and protein along with starches may enhance starch tolerance by slowing the digestive process and allowing more time for the food to pass through the small intestine and be exposed to the digestive enzymes. For example, when eating a potato add sour cream, cheese, and butter.

As patients with GSID grow older and their digestive tract lengthens, they can most likely increase the amount of starch in their diet.

Meats and Other Sources of Protein

Most patients with GSID can eat plain beef, plain pork, plain lamb, plain fish, plain turkey, plain chicken, and eggs. “Plain” meat means it is cooked without breading, sauces, and seasonings. Meats can be cooked with butter, oils, and salt and pepper. Processed meats such as bacon, sausage, luncheon meat, deli meat, liverwurst, and pâté, many of which are cured with sucrose or have starch fillers, should be avoided. Once appropriate sucrose and starch tolerance levels have been established, these food items may be added (one new food every three to five days).

Nuts and nut butters can be a great source of calories for a patient with GSID. Some nuts are higher in sucrose and starch, however, and should be avoided initially. Nuts and nut butters that are generally tolerated by those with GSID include almonds, Brazil nuts, hazelnuts, macadamia nuts, peanuts, pecans, pumpkin seeds, flax seeds, almond butter, and peanut butter. Legumes and beans are high in starch and should be avoided until starch tolerance has been established. Most patients with GSID can tolerate tofu.


Dairy products like cow’s milk, ricotta cheese, plain cottage cheese, sour cream, butter, cream, whipping cream, and hard cheeses (cheddar, colby, mozzarella, swiss, parmesan, and provolone) are foods most patients with GSID can eat. Patients with GSID should inspect food labels and ingredients in processed cheeses or cheese products since they may contain sucrose or starch fillers and would need to be avoided.

Plain, unsweetened yogurt, yogurt sweetened with dextrose, and yogurt sweetened with fructose are other foods most patients can tolerate. Many patients eat full-fat dairy products to ensure they are getting enough calories.

A minority of patients with GSID also have lactose intolerance. Those who are lactose intolerant should consult their physician or RD to see if milk products are able to be tolerated.


In general, most fats and oils, such as butter, margarine, olive oil, and vegetable oil, can be tolerated without restriction for patients with GSID. With regard to margarines, it is always a good idea to read labels carefully for potential starch or sucrose content. Olives and avocados are high in fat and may be beneficial to those with GSID who have increased calorie needs.


Typically, patients with GSID can tolerate milk, diet soda, water, and homemade limeade or lemonade made with fresh juice and fructose or dextrose. Many patients can tolerate regular sodas (non-diet) that are sweetened with high fructose corn syrup. Sweetened sodas should only be tried under the advice of an RD or physician.


In general, most patients with GSID can tolerate salt and pepper, as well as fresh herbs. However, many spices may contain sugar or starch fillers, so read the label carefully. It may be best to avoid seasonings initially during the two-week elimination diet. Once sucrose and starch tolerance levels have been established, herbs and spices may be added back to the diet. Remember to only add one new food (herb or spice) every three to five days to best determine tolerance.

Other Tips

Parents/caregivers have noticed a few trends that have contributed to raising tolerance levels when adding starch to a GSID diet.

First, thoroughly chew food. For example, chew 30 times before swallowing. Salivary amylase is the first enzyme to break down starch, so starchy foods will break down more easily if exposed to salivary amylase in the mouth for an extended period. The more a food is chewed, the greater the exposure the starchy food has to this necessary enzyme.

Second, the combination of a high-starch food with a fatty food at the time of ingestion assists in digestion. An example of this is combining cheese and a starchy vegetable. Food time spent in the small intestine affects starch digestion. Increasing the time through the small intestine by incorporating the high-fat content food will allow the starch to have more exposure to pancreatic amylase, isomaltase, and maltase in the small intestine.

Working with a RD who has experience with GSID patients is crucial for dietary success of GSID patients. The RD will be able to demonstrate how to effectively write and manage a food log/diary, and how to add foods to the diet. The RD can also utilize their network of fellow RD’s that may have experience with a GSID-friendly diet. At first the list may seem very short on food choices for someone with GSID, but be assured that over time, and by closely monitoring specific foods and related symptoms, the list of acceptable foods will continue to grow substantially.