Research reviewed by Gram found that a high-fat diet caused chronic high blood pressure in pregnant Dahl salt-sensitive rats, and that blood pressure stayed 10 to 15 mmHg higher than controls for at least 14 weeks after switching back to a normal diet. Pups were largely healthy, but the rats did not develop full preeclampsia.
According to research reviewed by Gram, a high-fat diet may cause long-lasting high blood pressure in female rats, even after they return to a normal diet. In a 2026 study published in the American Journal of Physiology, scientists fed one group of special lab rats a high-fat diet and another group a standard diet, both before and during pregnancy. The high-fat rats had high blood pressure for most of the study, and their pregnancies showed weaker blood vessel changes. Still, their pups were generally healthy. After the high-fat rats switched to a normal diet, their blood pressure stayed 10 to 15 mmHg higher than the control rats for at least 14 weeks. Neither group developed the full signs of preeclampsia, a serious pregnancy condition. The researchers say this rat model may help them study how body fat and chronic high blood pressure affect preeclampsia risk in people.
Key Statistics
A 2026 study published in the American Journal of Physiology found that female rats fed a high-fat diet had blood pressure 10 to 15 mmHg higher than control rats for at least 14 weeks after weaning.
In a 2026 rat study, high-fat-fed mothers had lower blood pressure during late pregnancy and released less protein in their urine than control mothers, though neither group developed full preeclampsia.
The Quick Take
- What they studied: Scientists wanted to know whether a high-fat diet in female rats, combined with a tendency toward high blood pressure, would produce pregnancy problems similar to preeclampsia in people.
- Who participated: The study used female Dahl salt-sensitive rats, a type of lab rat bred to develop high blood pressure when fed salt. The exact number of rats was not clearly reported in the summary provided. Some rats ate a high-fat diet and others ate a standard diet.
- Key finding: High-fat rats had high blood pressure before pregnancy and during most of pregnancy and nursing. Their blood pressure stayed 10 to 15 mmHg higher than control rats for at least 14 weeks after weaning, even after they switched to a normal diet. Neither group developed the full set of preeclampsia signs.
- What it means for you: This is an animal study, so it cannot tell you directly what to eat. It does suggest that a high-fat diet combined with existing high blood pressure may have lasting effects on blood pressure. People who are pregnant or planning pregnancy should talk with their doctor about blood pressure and diet.
The Research Details
Researchers started by feeding female Dahl salt-sensitive rats either a high-fat diet or a standard control diet. These rats are often used in studies of high blood pressure because they tend to develop it easily. The scientists then bred the rats and tracked their weight, blood pressure, kidney function, and blood vessel changes during pregnancy.
The team also measured how the rats’ bodies changed during pregnancy, including how they burned fat for energy and how the blood vessels that feed the placenta adapted. The placenta is the organ that connects a mother to her developing babies. The researchers checked outcomes such as litter size, how many pups survived, and how efficiently the placenta supported growth.
After weaning, some high-fat rats were switched to a standard diet. This let the researchers test whether changing diet could reverse the effects of the earlier high-fat eating. They then followed blood pressure for at least 14 weeks afterward.
Animal models let scientists control diet, genetics, and environment in ways that are not possible in human studies. Because preeclampsia is hard to study in people, a rat model that shows high blood pressure during pregnancy can help researchers test ideas about causes and possible protection. Following the rats over time also shows whether effects last after diet changes.
This is a single animal study, so results may not apply directly to people. The summary did not clearly report the total number of rats, which makes it harder to judge how strong the evidence is. The study was published in a respected physiology journal, and it measured several outcomes over time, which adds useful detail. Findings should be confirmed by other studies before drawing firm conclusions.
What the Results Show
The high-fat rats gained less weight during pregnancy than the control rats. Their bodies also produced more ketones, which are chemicals the body makes when it burns fat for fuel. The high-fat rats had heart and blood vessel changes and weaker adaptation of the blood vessels that supply the placenta.
Blood pressure was higher in the high-fat rats before pregnancy and during most of pregnancy and nursing. Both groups did show a drop in blood pressure in late pregnancy, which is unusual because preeclampsia usually causes blood pressure to rise late in pregnancy. The drop was lower in the high-fat rats, and they also released less protein in their urine.
Despite these changes, the high-fat rats had mostly normal pregnancy outcomes. Their litter sizes, pup survival, and placental efficiency were largely preserved. This suggests the rats’ bodies were adapting in ways that protected the pregnancy, at least in the short term.
The long-term results were the most concerning. Switching the high-fat rats to a normal diet did not reverse their high blood pressure. Their readings remained 10 to 15 mmHg higher than the control rats for at least 14 weeks after weaning.
The high-fat rats showed signs of stress on the heart and blood vessels, which are linked to long-term heart disease risk. The increase in ketones suggests changes in how the body used fuel during pregnancy. These findings point to metabolic changes that could affect health beyond the pregnancy itself. Researchers noted that the model may help them study the body’s natural ways of lowering preeclampsia risk.
Human studies have consistently linked obesity and chronic high blood pressure to a higher risk of preeclampsia. This rat study supports that connection while also showing that the rats did not develop the full condition. That suggests animal models may need further refinement to capture all parts of human preeclampsia.
The study used rats, and rats are not people. Pregnancy, diet, and blood pressure work differently in each species. The summary did not clearly state how many rats were studied, so the strength of the results is hard to judge. The study also did not produce the full signs of preeclampsia, which means it may not perfectly match the human condition. More research is needed to confirm these findings.
The Bottom Line
Research suggests that a high-fat diet combined with existing high blood pressure may cause lasting blood pressure problems, which is a moderate level of evidence in animals. Because this is a rat study, the findings are not yet strong enough to set firm diet rules for people. Generally, eating a balanced diet, limiting excess salt, and keeping a healthy weight are widely supported ways to support blood pressure. Anyone with concerns should speak with a healthcare provider.
People who are pregnant, planning pregnancy, living with obesity, or managing high blood pressure may find this research relevant. Researchers and doctors who study preeclampsia may also find the rat model useful. People without blood pressure concerns or pregnancy plans may find the results less directly applicable.
This study followed rats for several months, including at least 14 weeks after weaning. In people, changes in blood pressure from diet often take weeks to months to show up on measurements. Any real-world benefit from diet changes would need to be confirmed in human research over longer periods.
Frequently Asked Questions
Can a high-fat diet cause long-term high blood pressure?
A 2026 rat study found that female rats fed a high-fat diet stayed 10 to 15 mmHg higher in blood pressure than control rats for at least 14 weeks, even after switching to a normal diet. Because this was an animal study, human effects still need confirmation.
What is preeclampsia and how does it relate to blood pressure?
Preeclampsia is a serious pregnancy condition marked by high blood pressure and protein in the urine, usually appearing after 20 weeks of pregnancy. Research reviewed by Gram suggests that obesity and chronic high blood pressure are major risk factors for it.
Did the rats in the high-fat diet study have healthy pregnancies?
Mostly, yes. Litter size, pup survival, and placental efficiency were largely preserved in high-fat-fed rats. However, their blood pressure and blood vessel adaptation during pregnancy were impaired, and neither group developed full preeclampsia signs.
Does changing my diet reverse high blood pressure caused by fatty foods?
In this rat study, switching high-fat-fed rats to a normal diet did not reverse their hypertension. Their blood pressure remained elevated for at least 14 weeks afterward, suggesting that some effects of a high-fat diet may last longer than expected.
Want to Apply This Research?
- Record your home blood pressure at the same time each day, such as morning and evening, for 7 days per week. Also log your daily sodium intake and the share of calories that come from fat. Reviewing weekly averages can show whether your readings trend up or down over time.
- Try swapping one high-fat food per day for a lower-fat option, such as choosing grilled fish instead of fried meat. Track this change in the app for two weeks and note any shifts in your blood pressure averages. Share the results with your doctor if your readings stay high.
- Over several months, track blood pressure, weight, and diet patterns together to see how they relate. Set reminders for regular checkups and bring your app data to appointments. If you are pregnant or planning pregnancy, ask your provider how often you should check your blood pressure.
This article summarizes a laboratory study conducted in rats and is not medical advice. Animal results do not always apply to humans. If you are pregnant, planning pregnancy, or have concerns about blood pressure or diet, please consult a qualified healthcare provider.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.