Mar 03, 2026 12:00:00

A two-day oatmeal diet improves cholesterol levels and the effects last for more than a month, study finds

Oatmeal , a cereal made from oats (barley) processed for easy cooking, has been gaining attention in recent years as a health food because it is rich in dietary fiber, vitamins, minerals, and is low in calories. A new study showed that a diet centered on oatmeal for two days improved cholesterol levels, with the effect lasting for several weeks.

Cholesterol-lowering effects of oats induced by microbially produced phenolic metabolites in metabolic syndrome: a randomized controlled trial | Nature Communications
https://www.nature.com/articles/s41467-026-68303-9

Two days of oatmeal reduce cholesterol level — University of Bonn
https://www.uni-bonn.de/en/news/017-2026

48-Hour Oatmeal Diet Could Cut Cholesterol Levels For Weeks, Study Shows : ScienceAlert
https://www.sciencealert.com/48-hour-oatmeal-diet-could-cut-cholesterol-levels-for-weeks-study-shows

A research team at the University of Bonn in Germany conducted an experiment on 32 men and women with metabolic syndrome to investigate the health benefits of oatmeal.

Seventeen of the subjects followed a low-calorie diet consisting almost entirely of oatmeal for two days. These subjects consumed a total of 300g of boiled oatmeal per day, along with a small amount of fruit or vegetables, consuming less than half the calories they normally would. They were also prohibited from adding salt, sugar, or other sweeteners. The remaining 15 subjects served as a control group, who also followed the low-calorie diet for two days, but this diet did not include oatmeal.

The research team collected blood and stool samples from the subjects before the dietary changes and measured their blood pressure, weight, height, waist circumference, and body fat. They also collected and measured the same samples immediately after the two-day dietary changes, and two, four, and six weeks later.

Both groups benefited from the dietary changes, but the oatmeal group saw a greater reduction in total cholesterol by 8% and LDL (bad) cholesterol by 10%.

'The harmful bad cholesterol levels in particular were reduced by 10 percent, which is not comparable to the effects of modern medicines, but it's still a significant reduction,' said

Marie-Christine Simon , co-author of the study and a researcher at the University of Bonn's Institute of Nutrition and Food Science. 'They also lost an average of 2 kg in weight and had a slight drop in blood pressure.'

Furthermore, the research team analyzed blood and stool samples from the participants and found that oatmeal consumption increased the abundance of certain gut bacteria, which release phenolic compounds when they break down oatmeal, which have been shown to have a positive effect on cholesterol metabolism.

However, when the researchers conducted a second clinical trial in which 17 participants ate 80g of oatmeal per day for six weeks without any other dietary restrictions, they found some benefits but no significant reduction in cholesterol levels.

Although the study focused on subjects with metabolic syndrome and may not be applicable to the general population, the fact that bad cholesterol levels remained below baseline six weeks after the diet was completed suggests the researchers have uncovered a biological process worth further investigation.

'The next step will be to determine whether repeating the intensive oatmeal-based diet every six weeks actually has a lasting preventative effect,' Simon said.