A new study from the Journal of the American College of Cardiology (JACC) revealed that shakes shakes loaded with a lot of carbs can seriously cause damage to the heart, and shows that your favorite carb-heavy meal might have more of an effect than previously realized.

Researchers monitored 33 subjects after ingesting a carbohydrate-rich 264 calorie shake. You might expect their sugars to spike, but that’s not what the team behind the study were looking to analyze. Their aims were to see how the body’s response to digesting this mega-carb shake might alter the heart’s production of atrial natriuretic peptide (ANP). ANP is a cardiac hormone that helps the body filter out excess salt and reduces blood pressure. In this instance, it serves as a diagnostic marker enabling researchers to gauge heart function after a large amount of carbohydrates are consumed.

Over the course of several hours, participants’ ANP levels dropped by 25%. “The carbohydrate load had a significant and notable effect on circulating ANP levels. Experimental studies suggest that it’s not good to make less ANP,” said one of the researcher’s Thomas Wang, M.D., who confirmed that loading up on carbs may not be healthy for the body. For long-distance runners, who rely on this type of high-sugar sustenance to maintain energy for extended periods of time, these findings may find them turning elsewhere for nutrition.

Interestingly, researchers dug deeper to discover what caused those ANP levels to decrease. The answer? Glucose. “When you take in a high-carb shake a lot of things happen, including increases in glucose and insulin. However, the increase in glucose appears to be the main thing driving the drop in ANP levels,” Wang said.

Top 10 foods highest in carbs (carbohydrates)

Sugars, syrups and sweeteners
Candies
Cereals
Potato chips
Cookies
Refined flours
Jams and preserves
Breads
Potatoes
Sugary drinks