Quick Facts

• Eating 300 grams of oatmeal daily for 48 hours reduced LDL cholesterol by 10% and total cholesterol by 8%
• The effect lasted six weeks after participants returned to normal diets
• Gut bacteria break down oats into compounds that improve cholesterol metabolism

A two-day oatmeal diet can reduce harmful cholesterol levels by 10%, according to new research from the University of Bonn published in Nature Communications.

The study tracked 32 people with metabolic syndrome who ate 300 grams of oatmeal daily for 48 hours. Participants consumed 100 grams of rolled oat flakes boiled in water three times per day while cutting their normal calorie intake roughly in half.

Results showed LDL cholesterol levels dropped 10% and total cholesterol fell 8% in the oatmeal group. These improvements were significantly greater than those seen in a control group that reduced calories but did not eat oats.

“The level of particularly harmful LDL cholesterol fell by 10 percent for the oat group – that is a substantial reduction, although not entirely comparable to the effect of modern medications,” said Dr. Marie-Christine Simon, the study’s senior author.

The cholesterol benefits persisted six weeks after participants returned to their normal diets. The oat group also experienced weight loss and slight reductions in blood pressure.

Researchers identified the mechanism behind the improvements. Gut bacteria break down oats into phenolic compounds, particularly ferulic acid, which has been shown to improve cholesterol metabolism in animal studies.

“We were able to identify that the consumption of oatmeal increased the number of certain bacteria in the gut,” said lead author Linda Klümpen. “Intestinal bacteria produce phenolic compounds by breaking down the oats.”

The findings suggest it’s not just oats’ well-known beta-glucan fiber driving the benefits, but compounds produced when gut bacteria digest oats.

A separate six-week trial where 17 volunteers ate 80 grams of oats daily without other dietary restrictions did not produce the same rapid cholesterol improvements as the intensive 48-hour protocol.

High LDL cholesterol contributes to dangerous plaque buildup in arteries, raising heart attack and stroke risk. While a 10% reduction is meaningful, cholesterol medications can reduce LDL levels by 30% or more.

Simon suggests the approach could complement traditional treatments. “A short-term oat-based diet at regular intervals could be a well-tolerated way to keep the cholesterol level within the normal range and prevent diabetes,” she said.

The researchers plan to study whether repeating the intensive oat diet every six weeks provides permanent preventative effects. Larger studies are needed to confirm the findings.

Read more: The 48-Hour Oatmeal Diet That Could Improve Heart Health by 10%