Which is worse for inflammation, sugar or dairy?

November 18, 2025 •

4 min read

A diet high in refined sugar has been consistently linked to increased inflammatory markers in the blood. However, when considering which is worse for inflammation, sugar or dairy, the answer is not a simple one, as individual factors and types of food are critical.

Quick Summary

Refined sugar is a powerful pro-inflammatory agent for most people, linked to metabolic dysfunction. The impact of dairy, however, varies greatly depending on individual tolerance, gut health, and processing methods.

Key Points

Refined sugar is a consistent pro-inflammatory agent: It drives inflammation through multiple pathways, including blood sugar spikes, insulin resistance, and oxidative stress.
Dairy's inflammatory impact is highly individual: Unlike sugar, dairy's effect is conditional, depending on individual tolerance, allergies, or sensitivities.
Fermented dairy can be anti-inflammatory: Probiotic-rich options like yogurt and kefir can support gut health and reduce inflammatory markers for many people.
Processing matters for dairy: Processed, sugary dairy products are more likely to cause inflammation due to their high added sugar content, while plain versions are generally neutral or beneficial.
Sugar negatively impacts the gut microbiome: High-sugar diets can disrupt the balance of gut bacteria and increase intestinal permeability, further promoting inflammation.
Overall, refined sugar is the more reliable inflammatory culprit: For the general population, reducing added sugar is a more effective strategy for managing inflammation than eliminating dairy, unless a specific intolerance or allergy exists.

The Inflammatory Effects of Sugar

Refined sugars are among the most reliably pro-inflammatory culprits in the modern diet. Unlike the natural sugars found in whole foods, added and refined sugars trigger a systemic inflammatory response. The mechanisms behind this are well-documented and involve several key pathways.

How Refined Sugar Spurs Inflammation

High consumption of refined sugars leads to rapid spikes in blood glucose levels. The body responds by releasing insulin, and this constant cycle can lead to insulin resistance over time, which itself is a state of chronic, low-grade inflammation. Excess sugar is also converted by the liver into free fatty acids, which can trigger inflammatory processes in the body when digested. Excessive sugar consumption promotes the formation of advanced glycation end products (AGEs), harmful compounds that contribute to oxidative stress and inflammation.

The Gut Microbiome and Sugar

A high-sugar diet negatively impacts the delicate balance of the gut microbiome, promoting the growth of pro-inflammatory bacteria and potentially leading to increased intestinal permeability, or 'leaky gut'. This allows toxins and bacteria to pass into the bloodstream, further triggering an immune response and perpetuating inflammation.

The Inflammatory Profile of Dairy

The relationship between dairy and inflammation is far more nuanced and controversial. For the majority of the population without a pre-existing allergy or sensitivity, dairy is not consistently shown to be inflammatory. In fact, some studies indicate it may have neutral or even anti-inflammatory effects.

Individual Sensitivities and Dairy

Dairy's inflammatory potential is largely dependent on an individual's unique biology. Individuals with a cow's milk protein allergy will experience a significant immune-mediated inflammatory reaction to dairy, involving the release of histamine. Those with lactose intolerance, while not an immune reaction, can experience gut inflammation secondary to symptoms like bloating and diarrhea caused by malabsorption.

Fermented Dairy and Gut Health

Fermented dairy products, such as yogurt and kefir, contain probiotics that can actively promote a healthy gut microbiome, which is a cornerstone of reducing overall inflammation. These products can produce beneficial short-chain fatty acids (SCFAs), further strengthening the gut lining and reducing inflammatory markers. The fermentation process also reduces lactose content, making it more digestible for many.

Processed vs. Whole Dairy

The processing of dairy is another critical factor. Highly processed and sugar-sweetened dairy products like ice cream and flavored yogurts contain high amounts of added sugar, which negates any potential anti-inflammatory benefits and pushes the product into the pro-inflammatory category. Unsweetened, full-fat dairy contains saturated fats, but recent research challenges the idea that these fats are inherently inflammatory for most people and points to potential anti-inflammatory components instead.

Sugar vs. Dairy: A Direct Comparison


Aspect	Sugar (Refined & Added)	Dairy (Standard, Unflavored)	Dairy (Fermented)
General Population Effect	Pro-inflammatory for most	Neutral to beneficial for most	Anti-inflammatory due to probiotics
Metabolic Impact	Rapid blood sugar spikes, insulin resistance	Varied impact; potential for increased insulin release	Stabilizes blood sugar via probiotic effect
Gut Microbiome	Disrupts balance, increases gut permeability	Contains prebiotic components; requires individual tolerance	Promotes beneficial bacteria, improves gut barrier
Immune Response	Triggers pro-inflammatory cytokines	Neutral, except in cases of allergy	Modulates immune response
Key Takeaway	A direct and potent inflammation driver	Conditional risk, depending on individual and type	Generally considered beneficial for inflammation

Making the Right Choice for Your Body

To make informed dietary choices regarding sugar and dairy, consider the following steps:

Prioritize whole foods. The sugar in an apple, bound by fiber, is processed very differently than the refined sugar in soda. Opt for whole, unprocessed foods to reduce inflammatory load.
Listen to your body. Pay attention to how you feel after consuming dairy. If you experience digestive issues, skin flare-ups, or other symptoms, you may have a sensitivity or intolerance. An elimination diet can help confirm this.
Embrace fermented options. Fermented dairy like yogurt, kefir, and certain cheeses can offer anti-inflammatory benefits through their probiotic content.
Reduce added sugar. Cutting back on sugar-sweetened beverages and processed foods is a key strategy for reducing chronic inflammation.

Conclusion

Ultimately, refined and added sugar poses a more direct and reliable threat for exacerbating inflammation for the general population. Its consistent links to metabolic dysfunction, a compromised gut microbiome, and elevated inflammatory markers are well-established. Dairy, conversely, has a more complex and individual-dependent relationship with inflammation. For most people, especially when consumed in its less-processed, fermented forms, dairy is not inflammatory and may even offer benefits. The key lies in understanding your own body's response, opting for nutrient-dense whole foods, and significantly limiting refined sugars to better manage chronic inflammation and support long-term health.

According to Harvard Health, excess sugar consumption can lead to weight gain, inflammation, diabetes, and fatty liver disease, all of which are linked to an increased risk for heart attack and stroke.

Frequently Asked Questions

For individuals without a dairy allergy or lactose intolerance, refined and added sugar is reliably a more significant driver of systemic inflammation than dairy. Sugar promotes inflammation via multiple metabolic pathways, whereas moderate dairy intake is often neutral or even beneficial.

While lactose intolerance is not a classic immune-mediated allergy, the fermentation of undigested lactose in the gut can cause gastrointestinal symptoms like bloating and diarrhea, which can, in turn, cause low-grade gut inflammation.

No, many studies show that fermented dairy products like yogurt and kefir tend to have neutral to beneficial effects on inflammation. Their probiotic content helps support a healthy gut microbiome, which is crucial for regulating inflammation.

Refined sugar causes inflammation by triggering rapid blood sugar spikes, leading to insulin resistance, promoting oxidative stress, and disrupting the balance of the gut microbiome. These factors contribute to a state of chronic, low-grade inflammation.

For an anti-inflammatory approach, opt for fermented and unsweetened dairy products like plain yogurt, kefir, and some cheeses. Avoid highly processed and sugar-sweetened dairy, as the added sugar will increase inflammation.

Contrary to older beliefs, recent research suggests that full-fat dairy does not necessarily cause more inflammation. In fact, some studies indicate full-fat dairy may have neutral or even anti-inflammatory effects. The impact of saturated fat is complex and less inflammatory than previously thought for most individuals.

Many people with autoimmune diseases find relief by reducing their intake of refined sugar due to its powerful inflammatory effects. Dairy sensitivity can also be a trigger for some, so a guided elimination diet may be necessary to determine its individual effect.