Written by Alexa Heathorn, MS, CNS. Adults consuming the most pro-inflammatory diets had a 14% higher risk of developing metabolic syndrome over 18 years, with greater risks of abdominal obesity and elevated triglycerides, highlighting the importance of an overall anti-inflammatory dietary pattern for long-term metabolic health.

Metabolic syndrome (MetS) is a cluster of metabolic abnormalities that increase the risk of cardiovascular disease and type 2 diabetes. Diagnosis requires the presence of at least three of the following: elevated blood pressure, elevated fasting blood glucose, elevated triglycerides, low HDL cholesterol, and abdominal obesity.¹ As rates of urbanization, sedentary lifestyles, and poor dietary habits continue to rise, MetS has become an increasingly common global health concern.¹

Growing evidence suggests that chronic low-grade inflammation plays a central role in the development of MetS by promoting insulin resistance, abdominal fat accumulation, and abnormal lipid metabolism.¹ Consistent with this, individuals with MetS often have elevated inflammatory markers such as tumor necrosis factor-alpha (TNF-α), C-reactive protein (CRP), and interleukin-6 (IL-6).¹

Diet is one of the most important lifestyle factors influencing inflammation. Dietary patterns rich in fruits, vegetables, whole grains, omega-3 fatty acids, monounsaturated fats, antioxidant vitamins and minerals, and polyphenols are associated with lower levels of inflammation, whereas diets high in red and processed meats, refined grains, saturated and trans fats, fructose, cholesterol, and sugar-sweetened foods are associated with increased inflammatory activity.¹

The Comprehensive Dietary Inflammation Index (CDII) is a dietary scoring system that estimates the overall inflammatory potential of an individual’s diet. Although the CDII has been used to study relationships between diet and chronic disease, no previous prospective studies have evaluated whether a more pro-inflammatory diet, as measured by the CDII, is associated with the future development of metabolic syndrome.¹

Researchers investigated whether the inflammatory potential of the diet was associated with the future development of metabolic syndrome using data from the Korean Genome and Epidemiology Study (KoGES), a large prospective cohort. The analysis included 4,890 adults (mean age 50.4 years; 50.2% women) who were free of metabolic syndrome and major chronic diseases at baseline. Participants were followed for up to 18 years, with a mean follow-up of 10.9 years.¹

Dietary intake was assessed at baseline using a validated 103-item food frequency questionnaire. Researchers calculated each participant’s Comprehensive Dietary Inflammation Index (CDII) score, with higher scores representing a more pro-inflammatory diet. Participants were then divided into four groups based on their CDII score, ranging from the least inflammatory to the most inflammatory diets.¹

The primary outcome was the development of metabolic syndrome, defined as the presence of at least three of the following: elevated fasting blood glucose, elevated triglycerides, low HDL cholesterol, elevated blood pressure, or abdominal obesity. Researchers also evaluated each of these metabolic abnormalities individually to determine which components were most strongly associated with dietary inflammatory potential. Statistical analyses adjusted for multiple potential confounding factors, including age, sex, smoking status, alcohol intake, physical activity, education, income, occupation, and total energy intake.¹

During the 18-year follow-up period (mean follow-up: 10.9 years), 2,301 participants (47%) developed metabolic syndrome. Compared with participants consuming the least inflammatory diets, those in the highest CDII quartile (most pro-inflammatory diets) had a 14% higher risk of developing metabolic syndrome (HR 1.14, 95% CI 1.04–1.25, p = 0.006). Additionally, every one standard deviation increase in CDII score was associated with a 6% increase in metabolic syndrome risk (HR 1.06, 95% CI 1.02–1.10). Higher CDII scores were also associated with a significantly greater risk of developing abdominal obesity and hypertriglyceridemia, but were not significantly associated with elevated blood pressure, low HDL cholesterol, or hyperglycemia overall.

When individual dietary components were analyzed, higher intake of sugar-sweetened beverages was associated with an increased risk of metabolic syndrome and was also linked to a greater risk of abdominal obesity and elevated blood pressure. In contrast, higher low-fat dairy intake was associated with a lower risk of metabolic syndrome and was inversely associated with hypertriglyceridemia. Researchers also found that hyperglycemia was associated with higher intakes of organ meats and coffee, and lower intake of sweets and desserts. Finally, higher egg consumption was associated with a lower risk of developing low HDL cholesterol.

Several limitations should be considered when interpreting these findings. First, this was an observational study, meaning it can identify associations but cannot establish a cause-and-effect relationship between dietary inflammatory potential and metabolic syndrome. Second, dietary intake was assessed only once at baseline using a food frequency questionnaire, so changes in participants’ diets over the 18-year follow-up were not captured. Finally, although researchers adjusted for numerous lifestyle and demographic factors, the possibility of residual confounding from unmeasured variables cannot be completely excluded.

Future research should include randomized controlled trials to determine whether reducing the inflammatory potential of the diet can directly lower metabolic syndrome risk. Studies with improved participant follow-up, repeated dietary assessments, and more comprehensive measurement of potential confounding factors would also strengthen the evidence.

This prospective cohort study found that adults consuming pro-inflammatory diets had a significantly greater risk of developing metabolic syndrome over 18 years of follow-up. Higher dietary inflammatory potential was particularly associated with an increased risk of abdominal obesity and hypertriglyceridemia, while greater intake of sugar-sweetened beverages was linked to poorer metabolic health and low-fat dairy intake was associated with a lower risk of metabolic syndrome. Overall, these findings suggest that emphasizing an overall anti-inflammatory dietary pattern, rather than focusing on individual foods alone, may be an important strategy for reducing the long-term risk of metabolic syndrome. Additional randomized controlled trials are needed to determine whether lowering the inflammatory potential of the diet can directly prevent metabolic syndrome.

Click here to read the full text study.

Posted September 15, 2026.

Alexa Heathorn, MS, CNS-c, is a clinical nutritionist specializing in metabolic health, hormonal balance, and gastrointestinal restoration through root-cause functional nutrition. She earned her master’s degree in Nutrition from Bastyr University and is currently a Certified Nutrition Specialist (CNS) candidate. Alexa also works as a research writer and functional health consultant, translating complex science into actionable strategies for practitioners and wellness companies. Learn more at www.bloomedwellness.com.

References:

1. Kim SH, Kim H, Rebholz CM, Shin D. Association between the inflammatory potential of the diet and incidence of metabolic syndrome in middle-aged adults. Clin Nutr. 2026;63:106697. doi:10.1016/j.clnu.2026.106697