People who skip are more likely to have dangerous plaque buildup in their arteries, which puts them at increased risk for cardiovascular disease, according to a new study.
Skipping breakfast has been associated with being heavier and having higher cholesterol levels. But the new study, published in the Journal of the American College of Cardiology, linked it to the early stages of atherosclerosis, or the hardening and narrowing of arteries.
For the study, researchers analyzed dietary data from more than 4,000 men and women, ages 40 to 54, living in Spain. The people were then split into three groups, based on how many calories they had for their morning meal: less than 5%, between 5 and 20% or more than 20%.
Only about 3% of people fell into the first category, meaning they skipped breakfast entirely and only had coffee, juice or another beverage. The majority—about 69%—ate low-calorie breakfasts (like toast or small pastries), while the remaining 28% ate larger, substantial meals. The researchers didn’t further analyze each group’s breakfast breakdown, but it’s likely that the larger meals most closely represented what nutrition experts generally recommend for the first meal of the day: more whole grains, protein, healthy fats and fruits and fewer refined grains and added sugars.
Being in the first two categories—either skipping or skimping on breakfast—was associated with several risk factors for heart disease. People who ate less than 5% of their daily calories at breakfast were 2.5 times as likely to have generalized atherosclerosis—meaning their arteries had early signs of plaque in different locations—compared with those who ate the largest breakfasts. Those who had low-calorie breakfasts were at increased risk for early signs of plaque in their arteries, as well.
On average, people who skipped breakfast also had the greatest waist circumference and the highest body mass index, blood pressure, cholesterol and fasting glucose levels.
The study could not show a cause-and-effect relationship between skipping breakfast and any of these measures. In fact, the authors point out that people who skipped breakfast also tended to have more unhealthy lifestyles overall, including poor diets, frequent alcohol consumption and smoking. They were also more likely to be overweight or obese, so it’s possible that they didn’t eat breakfast as a strategy to lose weight.
But even when the authors adjusted for age, gender, smoking, drinking, cholesterol levels, waist circumference and daily intake of red meat and salt, the associations between breakfast-skipping and plaque remained—“suggesting that indeed skipping breakfast could be one of the risk factors clustering around the early onset and development of atherosclerosis,” the authors wrote in their paper.
In an accompanying editorial, researchers from the University of California, San Francisco, and the National Heart, Lung and Blood Institute wrote that skipping breakfast can cause hormonal imbalances and alter circadian rhythms, and that it can also contribute to people eating more calories—and more unhealthy foods—later in the day.
“The important message of this study, as pointed out by the authors, is that skipping breakfast serves as a marker of poor dietary and lifestyle choices that are linked to subclinical atherosclerosis,” they wrote in the paper.
The editorial authors write that educating the public about simple lifestyle changes—including an emphasis on a regular, hearty and nutritious breakfast—can help “curb the oncoming tsunami” of diabetes and cardiovascular disorders. “Indeed, the wisdom of the ages that breakfast is the most important meal of the day has been proven right in the light of emerging evidence,” they concluded.
This article originally appeared on Time.com