October 24, 2025, 1:43 am | Read time: 5 minutes

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Metabolic syndrome describes the simultaneous occurrence of several health disorders, including abdominal obesity, high blood pressure, elevated blood sugar levels, and disturbed blood lipid levels. It is considered a significant risk factor for cardiovascular diseases and type 2 diabetes–two of the most common diseases worldwide.

One possible influencing factor is breakfast behavior. While some studies link skipping breakfast to health risks, others show no clear effects. A comprehensive assessment of this inconsistent data was previously lacking.

The aim of the newly published systematic review with meta-analysis was to evaluate all available observational studies to clarify the link between skipping breakfast and the risk of metabolic syndrome and its individual components. The results are intended to provide a reliable basis for prevention recommendations.

Study Design and Methods

The analysis was conducted according to PRISMA and MOOSE guidelines. A total of four international databases (PubMed, Embase, Cochrane Library, Web of Science) were searched until May 2025.¹

Only observational studies (cross-sectional or cohort studies) that examined the link between breakfast behavior and metabolic syndrome or its components were included. Nine studies with a total of 118,385 participants from various countries–including Korea, Japan, Iran, Brazil, and the U.S.–met the inclusion criteria. The study quality was assessed using the Newcastle-Ottawa Scale. All included studies received at least six out of nine possible points.

Pooled odds ratios (OR) with confidence intervals were calculated to determine the disease risk associated with skipping breakfast compared to regular breakfast habits. Additionally, subgroup and sensitivity analyses were conducted to minimize bias and ensure the reliability of the results.

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Skipping Breakfast Measurably Increased the Risk of Metabolic Disorders

The meta-analysis shows a clear link between skipping breakfast and an increased risk of metabolic syndrome and its main components. People who regularly skipped breakfast had a significantly higher likelihood of suffering from one or more of these risk factors.

• Overall Metabolic Syndrome: The risk of developing metabolic syndrome was increased by ten percent with breakfast skipping. Even after excluding individual heterogeneous studies, this result remained statistically significant.
• Abdominal Obesity (Belly Fat): People who regularly skipped breakfast had a 17 percent higher risk of abdominal obesity–a particularly cardiovascular risky form of overweight.
• High Blood Pressure: The risk of elevated blood pressure increased by 21 percent with breakfast skipping. This link was particularly noticeable in studies that analyzed men and women separately.
• Hyperlipidemia (Elevated Blood Lipid Levels): The risk of disturbed blood lipid levels was also increased–skipping breakfast was associated with a 13 percent higher risk.
• Hyperglycemia (Elevated Blood Sugar): The strongest link was with blood sugar. People without breakfast had a 26 percent higher risk of elevated glucose levels–a warning sign for potential development of type 2 diabetes.

Despite some differing results in individual studies, the overall effect remained robust in all analyses. The sensitivity analyses confirmed the stability of the results, even after removing studies with high heterogeneity.

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What Do These Results Mean for Health?

The results show: Breakfast is more than a daily habit–it can be a crucial factor for metabolic health.

Metabolic syndrome is considered a warning system for serious diseases like heart attack, stroke, or type 2 diabetes. That a modifiable behavior like breakfast habits has a measurable effect on the risk of these diseases is highly relevant from a health policy and preventive medicine perspective.

The biological mechanisms behind the link are plausible: Prolonged fasting in the morning can disrupt the circadian rhythm, reduce insulin sensitivity, and lead to cravings and excessive energy intake later in the day. Increased activation of the sympathetic nervous system and hormonal imbalances have also been identified as possible consequences–all factors that can disrupt metabolic balance.

Important to note: The results refer to unstructured breakfast skipping, as often occurs in everyday life–not planned interval fasting. Structured fasting (such as intermittent fasting) can have positive metabolic effects under certain conditions. However, consciously and regularly skipping breakfast without compensation and planning was clearly associated with health risks in this meta-analysis.

Study Classification and Limitations

The study impresses with its comprehensive data base (over 118,000 participants), careful methodological approach, and use of internationally recognized evaluation criteria. The sensitivity analyses further strengthen the reliability.

However, it must be considered: These are observational studies. They show correlations but cannot prove causality. Other influencing factors such as overall diet quality, exercise, socioeconomic status, or sleep behavior could have affected the results.

In the evaluated studies, what was defined as “breakfast”–such as when and how much was eaten–was not always consistently defined. This complicates the comparison of results. Nevertheless, the evaluations overall showed a clear pattern: Those who regularly skip breakfast have a higher risk of metabolic disorders.