6 Foods That Cause Inflammation, According to a Dietitian

What Is Inflammation?

“Inflammation” is quite the buzzword in the health and wellness space, and you might be wondering what it means.

While not all inflammation is harmful, too much can become a problem.

Inflammation is the body’s immune response to stressors such as physical injury or illness. A small amount of inflammation is necessary to protect the body from harm. (1)

While short periods of inflammation are protective, recent studies have found that chronic inflammation may be unhealthy and lead to medical conditions such as: (2)

• Heart disease
• Chronic kidney disease
• Liver disease
• Cancer
• Autoimmune conditions, such as arthritis and diabetes type 2
• Disorders of the nervous system , such as Alzheimer’s disease and Parkinson’s disease

Research has determined that the quantity and the quality of nutrition have a powerful effect on inflammation in the body. As a result, nutrition affects the incidence, progression, and treatment of chronic disease. (3)

Understanding which foods are linked to chronic inflammation is essential for achieving a healthy lifestyle.

1. Excessive Refined Carbohydrates

There are two primary forms of carbohydrates, simple carbohydrates and complex carbohydrates.

Complex carbohydrates are higher in fiber and digest more slowly in the body than simple carbohydrates. (4)

Complex carbohydrates are an essential part of a healthy diet.

Examples of complex carbohydrates include:

• Whole grains
• Starchy and non-starchy vegetables, such as sweet potatoes, corn, peas, butternut squash, broccoli, cauliflower, beets, asparagus
• Legumes and beans
• Fruit

Simple carbohydrates are found in processed foods and refined sugars. They lack fiber and quickly digest the body. (4)

Examples of simple carbohydrates include:

• Candy
• Soda
• Syrups
• Sugar
• Processed flours, such as white bread, white pasta, and pastries

Without fiber, simple carbohydrates are broken down quickly, causing a rapid spike in your blood sugar.

Research has found a relationship between this blood-sugar spike and chronic low-grade inflammation. (5)

This consistent inflammation has been linked to inflammatory conditions such as type 2 diabetes, heart disease, and cancer. (5)

Additionally, research suggests that simple carbohydrates may encourage the growth of inflammatory gut bacteria, increasing the risk of obesity and associated medical conditions. (6)

Finally, researchers have found that simple carbohydrates account for 42% of daily calories in the average American diet, while complex carbohydrates only account for 9%. (7)

While simple carbohydrates can be enjoyed in moderation, 45% to 65% of your diet should be complex carbohydrates to avoid this carbohydrate-driven inflammatory response. (8)

2. Processed Meat

Research has linked increased consumption of red meat and processed meats to increased inflammation in the body. (9)

In particular, a 2015 review found a correlation between high red meat intake and an increased risk of developing colon cancer. (10)

A high intake of saturated fat is thought to trigger a series of inflammatory responses in fat tissue throughout the body. (11)

Examples of high-fat red meat include:

• Pork loin chop
• Burger meat
• Prime rib
• Beef ribs
• Beef short rib
• T-bone
• Lamb chops

Examples of processed red meat include:

• Bacon
• Sausage
• Hot dogs
• Pepperoni
• Ham

While red meat can be a part of a balanced diet, it is best to enjoy them in moderation. It is best to consume very little, if any, processed meats. (12)

The American Institute for Cancer Research currently recommends no more than three servings of red meat a week, a portion being three to four ounces, roughly the size of your palm. (12)

Finally, enjoying red meat alongside anti-inflammatory foods such as fruits and vegetables may help decrease the body's inflammatory response.

3. Trans Fat

Trans fat comes in two forms, naturally occurring and artificially made.

Small amounts of naturally occurring trans fats are present in some dairy and animal products.

Artificial trans fats are created in a process that adds hydrogen to liquid vegetable oils to make them more solid. (13)

These are called partially hydrogenated oils.

In 2015, the FDA ruled that trans fats were unsafe to eat, and the ban on trans fats in foods went into full effect in 2018. (14)

The primary dietary source of trans fats comes from industrially-made, partially-hydrogenated vegetable oils in processed foods.

Examples of these food sources include:

• Shortening
• Commercial baked goods
• Refrigerated doughs, such as rolls and biscuits
• Nondairy shelf-stable creamers
• Doughnuts
• Stick margarine

Both observational and experimental studies indicate that trans fats cause inflammation within the body. (15)

This inflammation has been linked to an increased risk for heart disease, diabetes type 2, high cholesterol, and insulin resistance. (15)

The American Heart Association recommends there is no safe level for intake of trans fats. (13)

While trans fats have been banned in the US, food manufacturers can round down to “0 grams” if a food contains 0.5 grams of trans fat. (16)

The best way to confirm you are avoiding any trans fats is to check the ingredients for partially hydrogenated oils.

4. Fried Foods

Fried foods are associated with an increased risk of developing chronic disease in adults. (17)

A 2019 review on women found that frequent consumption of fried foods has been associated with a higher risk of heart disease. (18)

Fried foods contain simple carbohydrates and saturated and trans fats, which have been linked to inflammation. (19)

Additionally, research has found that deep-fried foods contain a toxic byproduct that may further induce inflammatory markers in the blood. (20)

Examples of inflammatory fried foods include:

• French fries
• Doughnuts
• Fried chicken
• Chicken nuggets
• Deep-fried chips

The 2015–2020 Dietary Guidelines for Americans recommends limiting calories from saturated fats to less than 10% of a 2,000-calorie diet. This equates to 200 calories, or approximately 22 grams of saturated fat. (21)

If you are still looking to enjoy similar flavors of deep-fried food, switching to baking or air frying cooking method offers a less inflammatory alternative.

5. Sugar-Sweetened Beverages

Sugar-sweetened beverages are the most commonly consumed caloric beverage and the leading source of added sugars in the United States. (22)

Research has found that drinking 50 grams of sugar, the equivalent of a 16 oz soda, can cause a spike in inflammatory levels within 30 minutes. (23)

Additionally, inflammation remains high for over two hours. (24)

This inflammation is a critical factor in developing diabetes type 2 and heart disease. (25)

Added sugar also increases inflammation.

A sugar-sweetened beverage is a drink that has sugar added to it. This includes:

• Soda or pop
• Sports drinks
• Sweetened teas
• Sweetened coffee drinks
• Energy drinks
• Fruit juice with added sugar
• Sweetened lemonade
• Punch

For example, a venti caramel Frappuccino contains 73 grams of sugar, equivalent to 18 teaspoons. (26)

The American Heart Association suggests no more than 100 calories of added sugar per day for women. This is about six teaspoons or 24 grams of sugar.

The recommendation for men is no more than 150 calories per day, about nine teaspoons or 36 grams of sugar. (27)

There’s no nutritional need or benefit from eating added sugar, so eliminating it as much as possible helps reduce its inflammatory effects.

6. Alcohol

It is not uncommon for people to unwind from a stressful day by drinking alcohol.

However, while alcohol consumption may feel like a way to relax, excessive intake can create added stress on the body.

Research has found a link between excessive alcohol intake and intestinal inflammation. (28)

Furthermore, alcohol-induced intestinal inflammation may alter your healthy gut bacteria and increase the permeability of the intestinal lining, leading to a weakening of the immune system. (28)

Alternatively, some research suggests a mild intake of alcohol may decrease inflammatory markers, protecting against conditions such as rheumatoid arthritis. (29)

The key here is a mild intake, which researchers determined to be less than a glass of beer or wine daily.

Finally, while mild intake may not be harmful, alcohol is not necessary for optimal health and may lead to chronic inflammation if taken in excess.

Frequently Asked Questions

The Bottom Line

Inflammation is the body's protective response to stress, such as illness and injury.

While short-term inflammation is safe and even necessary, persistent inflammation may lead to medical conditions, such as:

• Heart disease
• Chronic kidney disease
• Liver disease
• Cancer
• Autoimmune conditions, such as arthritis and diabetes type 2
• Disorders of the nervous system, such as Alzheimer’s disease and Parkinson’s disease

Research has found that the quality of nutrition has a profound impact on inflammation. (3)

Foods related to increased inflammation throughout the body include:

• Processed carbohydrates
• Red meats and processed meats
• Trans fats
• Fried foods
• Sugar-sweetened beverages
• Alcohol

Limiting the intake of inflammatory foods may decrease risk factors for diet-induced inflammation.