The most well-established inflammatory foods are refined carbohydrates, sugar-sweetened drinks, fried foods, processed meats, and foods containing artificial trans fats. These aren’t inflammatory in a vague, hand-wavy sense. They raise measurable markers of inflammation in your blood, and that chronic, low-grade inflammation is a key driver of heart disease, type 2 diabetes, and other serious conditions.
What’s worth understanding is that these foods don’t just cause inflammation by making you gain weight. Even after researchers account for obesity, the link between these foods and inflammation holds. Some of these ingredients appear to trigger inflammatory pathways on their own, regardless of the extra calories.
Added Sugar and Sweetened Drinks
Sugar is one of the most studied inflammatory triggers. In intervention studies, people consuming 80 grams of added fructose or sucrose per day saw their levels of C-reactive protein (a key inflammation marker in the blood) rise by over 100% compared to baseline. Even at lower doses of around 40 grams per day, inflammation markers still climbed, just not as steeply. For context, a single 20-ounce bottle of soda contains about 65 grams of sugar.
The type of sugar matters somewhat. Fructose and sucrose consistently drive inflammation markers higher than glucose alone, though glucose isn’t harmless either. One study found that fructose raised C-reactive protein by 4% while glucose actually lowered it by 23% at the same dose, suggesting fructose is the bigger problem. This is relevant because high-fructose corn syrup, found in sodas, fruit drinks, and many packaged foods, is one of the most common sweeteners in the American diet.
The latest U.S. Dietary Guidelines, released in 2025, take a hard line: no amount of added sugar is considered part of a healthy diet. As a practical cap, the guidelines recommend no single meal contain more than 10 grams of added sugars. They also now advise children avoid added sugars entirely until age 10.
Refined Carbohydrates
White bread, pastries, white rice, and other refined grains behave similarly to sugar in your body. They’re digested quickly, causing rapid blood sugar spikes. This matters for inflammation because those sharp glucose surges activate the same inflammatory signaling pathways that sugar does.
A systematic review of 13 clinical trials examining high-glycemic diets (the kind built on refined carbs) found that about half showed significant inflammatory effects or strong trends toward them. Three trials found clearly higher inflammation on high-glycemic diets, and four more showed the same pattern in subgroups or trends. The evidence isn’t as dramatic as it is for sugar, but it points in the same direction: the faster a carbohydrate hits your bloodstream, the more inflammatory it tends to be. Whole grains, which are digested slowly and keep blood sugar stable, don’t have this effect.
Processed and Red Meat
Hot dogs, sausage, bacon, and deli meats are consistently linked to higher inflammation. One reason is that processing and high-heat cooking create compounds called advanced glycation end products (AGEs), which promote oxidative stress and chronic inflammation. Grilling, frying, or broiling any meat increases AGE formation, but processed meats start with higher levels because of the curing, smoking, and preserving steps they go through before they even reach your kitchen.
Red meat in general, including burgers and steaks, also appears on most lists of inflammatory foods. The connection is strong enough that Harvard’s nutrition researchers group it alongside fried foods and soda as a food to limit. The mechanisms likely involve both AGEs and other compounds generated during high-temperature cooking, as well as the saturated fat content.
Artificial Trans Fats
Artificial trans fats are among the most directly inflammatory substances in the food supply. Lab research shows that the specific trans fats found in partially hydrogenated oils (elaidic acid and linoelaidic acid) double the production of damaging reactive oxygen species in blood vessel cells. These compounds also activate a master inflammatory switch inside cells, ramping up production of inflammatory signaling molecules and adhesion molecules that pull immune cells into vessel walls.
Perhaps more importantly, trans fats simultaneously reduce the production of nitric oxide, the molecule that keeps blood vessels relaxed and healthy. So they hit you twice: increasing inflammation while also impairing the body’s built-in protective mechanisms. This combination helps explain why trans fats are so strongly linked to heart disease.
While the FDA effectively banned partially hydrogenated oils in 2018, trans fats haven’t disappeared entirely. They still show up in some imported foods, certain fried restaurant items, and products that contain less than 0.5 grams per serving (which can be legally labeled as “0 grams trans fat”). Margarine, shortening, and lard remain on Harvard’s list of inflammatory foods to limit.
Fried Foods
Frying creates a triple problem. It introduces large amounts of oil (often reheated, which degrades into more harmful compounds), generates AGEs on the food’s surface, and dramatically increases calorie density. French fries, fried chicken, and doughnuts are among the worst offenders. Repeated frying in the same oil, common in restaurants, generates progressively more oxidized fats that are particularly inflammatory.
Food Additives and Emulsifiers
A growing body of evidence points to common food additives as a less obvious source of inflammation, primarily through their effects on your gut. A randomized, placebo-controlled trial tested five dietary emulsifiers (ingredients used to keep processed foods smooth and shelf-stable) in healthy volunteers over six weeks. The results were telling.
People consuming carboxymethyl cellulose, a common thickener found in ice cream, sauces, and gluten-free baked goods, had significantly lower levels of short-chain fatty acids. These fatty acids are produced by healthy gut bacteria and play a major role in keeping your intestinal lining intact and inflammation in check. People consuming carrageenan, another common additive found in dairy alternatives and deli meats, showed increased intestinal permeability, meaning their gut lining became more “leaky.” When the gut barrier weakens, bacterial components can slip into the bloodstream and trigger systemic inflammation.
These findings don’t mean every additive is dangerous, but they suggest that a diet heavy in ultra-processed foods introduces compounds that quietly undermine gut health.
Alcohol Beyond Moderate Amounts
Alcohol’s relationship with inflammation follows a J-shaped curve. Small amounts may be neutral or mildly anti-inflammatory, but beyond a threshold, inflammation climbs sharply. In women, C-reactive protein levels were lowest among those drinking up to 15 grams of alcohol per day (roughly one standard drink). At more than 30 grams per day (about two to three drinks), CRP levels jumped to 3.18 mg/L, higher than in non-drinkers. The pattern held even after adjusting for body weight and other factors.
What About Dairy?
Dairy is often assumed to be inflammatory, but the research tells a more complicated story. A large meta-analysis of randomized controlled trials actually found that higher dairy consumption reduced several inflammation markers, including C-reactive protein, compared to low or no dairy intake. Low-fat yogurt in particular showed anti-inflammatory effects in premenopausal women and overweight individuals.
However, when researchers looked only at the most rigorous study designs (crossover trials, where the same people serve as their own controls), the benefits disappeared. The honest summary is that dairy doesn’t appear to be inflammatory for most people, and may even be mildly anti-inflammatory, but the evidence isn’t strong enough to make definitive claims. If you tolerate dairy well, there’s no compelling reason to cut it out for inflammation purposes.
The Common Thread
The foods that consistently drive inflammation share a few features: they spike blood sugar rapidly, they contain fats that have been chemically altered or damaged by heat, or they introduce additives that disrupt gut bacteria. The pattern maps closely onto what’s commonly called the Western diet, heavy on processed and packaged foods, light on whole plants, fiber, and omega-3 fats. Most Americans eat roughly 10 times more omega-6 fats than omega-3 fats. The fix isn’t to obsessively avoid omega-6s (the American Heart Association says that’s unnecessary) but to add more omega-3 sources like fatty fish, walnuts, and flaxseed to bring things into better balance.
You don’t need to eliminate every item on this list to make a difference. Inflammation responds to overall dietary patterns, not individual meals. Shifting your baseline away from processed foods, added sugars, and fried items, and toward whole grains, vegetables, and fish, moves multiple inflammatory markers in the right direction at once.