Food allergies or sensitivities, religious practices, and ideological beliefs are some of the main reasons people rely on specific diets or follow dietary restrictions.

While some restrictions are meant to prevent life threatening events, others speak to your guest’s personal and moral beliefs. Either way, they’re equally important.

Therefore, if you’re planning an event — or catering for one — it would be best to become familiarized with some of the most common dietary restrictions.

Here are 10 dietary restrictions you should know about.

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Lactose intolerance is a digestive disorder caused by a deficiency of the enzyme lactase, which helps digests lactose — the main type of carb in milk (1, 2).

However, about two-thirds of the world’s population stops producing the enzyme after weaning. Thus, they become lactose intolerant (2, 3).

Having lactose intolerance means that symptoms like bloating, abdominal pain, flatulence, and diarrhea, may occur after consuming lactose-containing foods, including milk and milk products (1, 2).

However, studies suggest that some people with lactose intolerance may consume up to 12 grams of lactose per day without showing symptoms — roughly the amount of lactose in an 8 ounce (240 mL) cup of milk (1, 2).

Current treatments for lactose intolerance include reducing or eliminating its intake or taking lactase pills. Nevertheless, not all milk products are the same, and people may tolerate some products better than others.

Here are some milk product recommendations to consider when planning your event’s menu (1, 4):

  • Lactose-free milk. This milk alternative is simply milk treated with lactase, which digests lactose for you. It’s nutritionally identical to regular milk, only slightly sweeter.
  • Fermented dairy products. People with lactose intolerance may be able to tolerate yogurt, kefir, sour cream, Leben, labneh, mursik, and viili due to the partial digestion of lactose via bacterial fermentation.
  • Hard-mature cheeses. Cheeses such as Parmesan and Granna Padano are naturally lactose-free and may be tolerated by most people.
  • Butter. While butter comprises the fatty fraction of milk, it may contain residual lactose. However, clarified butter or ghee is generally safe for people with lactose intolerance.

People with lactose intolerance have trouble digesting lactose-containing foods such as milk and some milk products. They are better off when presented with lactose-free alternatives.

Gluten is one of the main proteins in wheat, but it’s also found in barley and rye. It’s responsible for giving elasticity and viscosity to baked goods (5, 6).

However, two gluten-related disorders affect 1–7% of people worldwide. They’re celiac disease and non-celiac gluten sensitivity (5).

Celiac disease is a gluten-induced autoimmune disorder that leads to inflammation and damage to the small intestine (5, 7).

Common symptoms of celiac disease include abdominal pain, diarrhea, and weight loss due to nutrient malabsorption. Other atypical symptoms include skin rashes, anemia, and osteoporosis (5, 7).

On the other hand, non-celiac gluten sensitivity is a nonallergic and nonautoimmune condition also caused by gluten consumption that leads to symptoms similar to those of celiac disease (5, 8, 9).

Aside from reacting to gluten-containing foods, people with non-celiac gluten sensitivity also tend to present multiple food intolerances, including those to cow’s milk, egg, and other foods (8).

Current treatments for both disorders rely on following a strict and lifelong gluten-free diet (7, 9, 10, 11).

This means that foods containing ingredients made from wheat, barley, and rye, such as bread, pasta, cereal, crackers, baked goods, and beer, are off-limits. Some people with celiac disease may also react to oats due to cross contamination during processing (7).

Instead, you may rely on naturally gluten-free grains, starches, and flours, such as rice, quinoa, corn, tapioca, millet, amaranth, buckwheat, sorghum, potatoes, yucca, plantain, beans, lentils, and chickpeas.


Gluten-free diets help prevent health complications among people with celiac disease and non-celiac gluten sensitivity caused by gluten consumption. This means that foods and ingredients like wheat, barley, and rye should be avoided.

Vegetarianism is a dietary pattern that relies mainly on plant-based foods and avoids meats, poultry, and fish.

However, multiple variations allow for some animal-based foods, including (12):

  • Lacto-vegetarians: exclude meat, poultry, and fish but include milk and milk products
  • Ovo-vegetarians: exclude meat, poultry, and fish but includes eggs
  • Lacto-ovo-vegetarians: exclude meat, poultry, and fish but includes milk, milk products, and eggs
  • Pescatarians: exclude meat and poultry but includes fish, milk, milk products, and eggs
  • Semi-vegetarians or flexitarians: mostly vegetarians that occasionally consume meat, meat products, poultry, and fish

Since animal-based protein sources are either limited or avoided on a vegetarian diet, including plant-based proteins in your menu would be ideal.

Try to emphasize pulses or legumes (peas, beans, chickpeas, and lentils), quinoa, soy, and soy-derived products like tofu or tempeh (13, 14).

Other important plant-derived foods include fruits, vegetables, whole grains, nuts, and seeds (15).


Vegetarians primarily eat plant-based foods and avoid meat, poultry, and fish. However, some forms of vegetarianism may allow for dairy, eggs, fish, and even meat.

Vegan diets are a stricter form of vegetarianism in which all animal and animal-derived foods are avoided (15, 16).

This means that ingredients like gelatin, fish-derived sauces, honey, bee pollen, casein, and whey, are off-limits.

Veganism is mainly linked to religious, ethical, and environmental beliefs. However, it may also provide some health benefits, including weight loss and a lower risk of chronic diseases like heart disease, some cancers, and type 2 diabetes (17, 18, 19).

Like vegetarianism, veganism has its variations.

These include the fruitarian diet, which relies on fruits, nuts, seeds, some vegetables, as well as the raw vegan diet, which primarily relies on uncooked plant-based foods (12, 20).

Make sure to include various whole grains, fruits, vegetables, and plant-based protein sources — both cooked and raw when possible — if hosting a vegan event.


Vegans rely solely on plant-based foods and avoid all types of animal and animal-derived foods and products.

Kosher refers to the dietary principles followed by Jewish law, which dictates which foods are allowed.

Generally, a kosher diet centers around three main features: allowed animals, the prohibition of blood, and the prohibition of mixing dairy and meat (21).

However, other aspects must be considered to deem a food as kosher, including the slaughtering and meat processing method.

Here’s a list of the main considerations to keep in mind when planning a kosher menu:

  • Meat. Meat and meat products must come from the forequarters of ruminant animals with split hooves, such as cows, lambs, goats, sheep, deer, and oxen.
  • Dairy. Dairy products like milk, cheese, and yogurt must come from kosher animals and can’t be mixed with meat and poultry. Some people wait up to 6 hours to consume dairy after eating meat or poultry.
  • Fish. Fish must have fins and scales simultaneously to be considered kosher. This includes sardines, anchovies, salmon, tuna, and mackerel.
  • Poultry. Chicken, turkey, goose, quail, and dove are permitted.
  • Slaughtering method. Animals for meat, poultry, and dairy products must be slaughtered in a specific way by a certified butcher.
  • Prohibition of blood. You must remove all blood from meat, poultry, and eggs before cooking to ensure the cleanliness of the food.
  • Pareve. Pareve refers to foods considered neutral for mixing purposes, meaning that you can serve them with either meat or dairy. They include fish, eggs, grains, nuts, fruits, and vegetables.
  • Equipment. Utensils used to prepare, clean, and serve food should only be used for kosher foods to avoid contamination with nonkosher ones. You can’t use the same utensils to prepare meat and dairy.

As for foods to avoid, the kosher diet also explicitly prohibits pork meat.


Kosher refers to the Jewish dietary law. It states which foods are allowed and prohibited, as well as how to prepare and process them.

The ketogenic, or keto, diet is a high fat, very low carb diet that has gained popularity in the last few years.

While weight loss is one of the main reasons behind the diet’s popularity, some may follow it for its blood-sugar benefits and other metabolic effects (22, 23).

The keto diet restricts carbs to 20–50 grams per day while encouraging an intake of up to 70% of your daily calories from fat (22).

This means that grains, legumes, starchy vegetables, and most fruits must be limited or eliminated, along with high sugar foods like candy, fruit juices, sodas, and desserts.

If you’re accommodating someone following a keto diet, make sure your menu includes:

  • Protein: meat, chicken, fish, eggs, turkey, processed meats, cheese, and plant-based proteins such as tofu or tempeh
  • Fats: nuts, seeds, cream cheese, butter, avocado, and healthy oils like coconut or olive oil
  • Nonstarchy vegetables: cucumber, tomatoes, leafy greens, onions, broccoli, etc
  • Low sugar fruits: moderate amounts of berries

The keto diet limits carbs to 20–50 grams per day. Therefore, grains, legumes, most fruits, and starchy vegetables are not allowed. Instead, protein, fats, and nonstarchy vegetables are permitted.

People with diabetes have an impaired ability to metabolize carbs either because they produce little to no insulin (type 1 diabetes) or can’t absorb insulin (type 2 diabetes) (24).

Insulin is the hormone that allows sugar from carbs to enter your cells. Thus, if its production or action is impaired, it may lead to high blood sugar levels (24).

Dietary recommendations for people with diabetes promote a healthy eating pattern that includes moderate amounts of all food groups.

Some healthcare professionals suggest focusing on foods with a low glycemic index (GI), which won’t spike blood sugar levels after consuming them (25).

These include high fiber foods like whole grains and legumes, as well as certain lower sugar fruits, such as berries, melons, and apples (26).

Other foods you may include for a diabetes-friendly menu include lean proteins, dairy, and starchy and nonstarchy vegetables.

However, make sure to limit sugary drinks, dressings, and sauces, along with refined grains, sweets, and desserts.


A diabetes-friendly diet provides moderate amounts of foods from all food groups while limiting refined grains and high sugar foods.

A dairy-free diet differs from a lactose-free diet in that it excludes all dairy products, including cheese, yogurt, and other fermented products, as well as cream, and butter.

Unlike lactose intolerance, in which other milk nutrients are well tolerated, dairy-free diets are often part of cow’s milk allergy treatment.

A cow’s milk allergy is an allergic reaction to the proteins in cow’s milk — either casein or whey. In those with a cow’s milk allergy, the immune system triggers a response when it recognizes the presence of either or both of them (27).

Therefore, make sure to eliminate all dairy products from your menu if hosting an event for people with this allergy, and consider plant-based dairy substitutes made from nuts, seeds, and nondairy milks.


Dairy-free diets eliminate milk and milk products, including cheese, butter, yogurt, and other fermented products and lactose-free varieties.

Low carb diets are very similar to the keto diet in that both restrict carbs to keep insulin levels low throughout the day.

There isn’t a specific way to follow a low carb diet. As such, there are many variations with strict and flexible carb allowances. Still, they usually stay below 120 grams of carbs per day (28).

Furthermore, they all limit alcohol, refined sugar, and highly processed foods.

Overall, avoid serving sugary drinks, white bread, pasta, and rice, and limit the number of starchy vegetables, grains, and legumes on your menu.

Instead, emphasize animal-based proteins, nonstarchy vegetables, fruits, nuts, seeds, and other healthy fat choices like avocado and olives.


Low carb dietary restrictions are very similar to the keto diet. Make sure to emphasize animal-based proteins, nonstarchy vegetables, and healthy fats while limiting grains, sugary, and processed foods.

Food allergies lead to adverse reactions from your immune system when consuming certain foods.

They affect about 10% of adults and 8% of children worldwide, and some may lead to life threatening reactions (29, 30).

Here’s a list of some of the most common food allergies:

  • Wheat. Wheat is one of the most common allergens, leading to adverse reactions to wheat ingredients (4).
  • Nuts. This category includes peanuts and tree nuts, namely almonds, Brazil nuts, walnuts, hazelnut, cashews, pine nuts, macadamia nuts, and pistachios. They’re most common in children, as about 15–22% outgrow them (31, 32).
  • Fish and shellfish. Fish allergies may be caused by the intake, handling, or inhalation of fish, toxins, and parasites. A shellfish allergy is commonly caused by the intake of shrimps, crabs, lobsters, clams, oysters, and mussels (33, 34).
  • Eggs. People with egg allergies may react to both the white and the yolk. It’s also important to account for foods that contain eggs, such as baked goods or pasta (35).
  • Soy. Soy allergies are more common in children, who may react to soy and soy products and even peanuts due to the similarity between their proteins (36).

Currently, the most effective treatment for a food allergy is the complete elimination of the food. Thus, make sure to account for guests with any potential allergies for a successful event (37).


Food allergies may lead to life threatening reactions when consuming certain foods. The most common ones include wheat, eggs, soy, fish, shellfish, and nuts.

Whether it’s for religious, moral, or health reasons, certain foods are off-limits for some people.

Therefore, knowing about your guest’s or client’s dietary restrictions is key to planning a successful event.

This list comprises 10 of the most common restrictions. However, make sure to ask ahead to avoid any mistakes.