Rosemary extract and weight gain in mice on a fatty diet
What it found
In mice fed a high-fat diet, rosemary extract lowered weight gain, body fat, blood sugar and liver fat over 16 weeks.
The effect was seen in animals, not people.
What they found
Animal and lab studies
Weight and body fat
Mice given rosemary extract gained less weight and had a lower percentage of body fat than mice eating only a high-fat diet.
Blood sugar and insulin
Blood sugar and insulin levels were lower in mice that received the extract compared to those on the plain high-fat diet.
Liver health markers
The extract reduced liver weight, liver fat stores and certain liver enzymes in the blood. Liver cells also showed less fat buildup under a microscope.
Oxidative stress markers
Mice given the extract had lower levels of substances linked to cell damage. Their livers also showed better antioxidant activity than mice on the high-fat diet alone.
Fat passing through gut
The extract increased the amount of fat leaving the body in droppings. This suggests it blocked some fat from being absorbed in the gut.
What the authors conclude
- They conclude that rosemary is a promising dietary ingredient for lowering the chance of obesity and related metabolic problems.
How it was done
The authors wanted to see if carnosic acid, a key part of rosemary extract, could help prevent weight gain and related metabolic problems caused by a fatty diet.
Mice were fed either a low-fat diet, a high-fat diet, or a high-fat diet mixed with rosemary extract for 16 weeks. The extracts contained different amounts of carnosic acid, ranging from 0.14% to 0.5% of the food by weight.
What it can’t tell you
- We summarised it from the abstract only.
- These results come from mice, so they cannot show what happens in people eating rosemary extract. The study tested specific doses mixed into animal feed, which may differ from how people consume it.
Who paid
- Authors work at
- North Carolina Agricultural and Technical State University, United States
The paper
- Title
- Carnosic acid as a major bioactive component in rosemary extract ameliorates high-fat-diet-induced obesity and metabolic syndrome in mice
- Type
- Study
- Evidence
- Animals and lab studies
- Summarised from
- Abstract only
- Cite
- Zhao Y, Sedighi R, Wang P, Chen H, Zhu Y, Sang S (2015). Carnosic acid as a major bioactive component in rosemary extract ameliorates high-fat-diet-induced obesity and metabolic syndrome in mice. Journal of agricultural and food chemistry. doi:10.1021/acs.jafc.5b01246PubMed 25929334DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error