Researchers studied whether changing what sick hearts eat could help them work better. They gave pigs with weakened hearts either a high-fat diet or a regular diet for two months. The pigs eating the high-fat diet showed significant improvement in how well their hearts pumped blood, while the control group didn’t improve much. The study suggests that by switching the heart’s fuel source back to fats, the organ can heal itself and function better. However, this is early research in animals, and more studies are needed before doctors might recommend this approach to heart patients.
The Quick Take
- What they studied: Whether feeding a high-fat diet to animals with weakened hearts could improve how well their hearts pump blood
- Who participated: 19 pigs that were given heart damage similar to human heart failure, then randomly assigned to eat either a high-fat diet (with added lard) or a regular diet for two months
- Key finding: Pigs on the high-fat diet showed their heart’s pumping ability improve from 38% to 54% efficiency, while control pigs only improved from 36% to 41%. The high-fat diet group also had less scarring in their hearts and their heart cells switched back to using fat as fuel instead of glucose.
- What it means for you: This research suggests that diet might help damaged hearts recover, but it’s very early-stage animal research. People with heart failure should not change their diet based on this study alone—always talk to your doctor first, as heart failure treatment is complex and individual.
The Research Details
Scientists created heart damage in 19 pigs by slowly blocking their coronary arteries (the blood vessels that feed the heart). This mimicked how human hearts fail. Once the pigs developed weakened hearts similar to human heart failure, the researchers split them into two groups: one group ate a regular diet, and the other ate a diet with 20% added lard (a high-fat diet). Both groups ate their assigned diet for two months.
Before and after the diet period, researchers took detailed pictures of each pig’s heart using advanced imaging technology (cardiac MRI and PET scans) to measure how well the heart was pumping and how the heart cells were using fuel. After two months, the pigs were humanely euthanized and their hearts were examined under microscopes to see what had changed at the cellular level.
This type of study in large animals like pigs is important because pig hearts are similar to human hearts in many ways, making the findings more relevant to potential human applications than studies in smaller animals.
Understanding how to change a failing heart’s metabolism (the way it uses fuel) could open new treatment options. Most current heart failure treatments focus on reducing the workload on the heart or improving blood flow, but this research explores whether we can actually reprogram how the heart uses energy. If successful in humans, this could represent a completely different approach to treating heart failure.
This is a well-designed animal study with several strengths: it used a reasonable number of animals (19), included both before-and-after measurements, used advanced imaging technology to track changes, and examined the hearts at the cellular level. However, the study is small, was conducted in animals (not humans), and was published as early-stage research. The findings are promising but preliminary and need confirmation in larger studies and eventually in human trials.
What the Results Show
The main finding was dramatic: pigs eating the high-fat diet showed significant improvement in their heart’s pumping ability. Their left ventricular ejection fraction (a measure of how much blood the heart pumps with each beat) improved from 38% to 54%—a 16-point improvement. In contrast, pigs eating the regular diet only improved from 36% to 41%, a 5-point improvement that wasn’t statistically significant.
The high-fat diet group also showed less scarring in their hearts. Scarring is a major problem in heart failure because it makes the heart stiff and less able to pump. The high-fat diet pigs had only 0.45% scarring compared to 6.23% in the control group—more than a 10-fold difference.
Perhaps most importantly, the researchers found that the high-fat diet reversed an unhealthy change in how the heart cells used fuel. In heart failure, damaged hearts switch from burning fat (their preferred fuel) to burning glucose (sugar). This metabolic switch is thought to be harmful. Only the high-fat diet group showed a reversal of this switch, with their heart cells returning to using fat as their main fuel source.
At the cellular level, hearts from the high-fat diet group showed healthier mitochondria (the energy factories inside cells) and better organization of lipid droplets (fat storage units), suggesting the cells were functioning more normally.
Gene expression analysis revealed that the high-fat diet activated genes responsible for burning fat and deactivated genes that import glucose into heart cells. This molecular-level change supports the idea that the diet fundamentally reprogrammed how the heart cells operate. The mitochondria in heart cells from the high-fat group were less fragmented (broken apart), which is associated with better cellular function. These findings all point to the same conclusion: the high-fat diet helped restore the heart’s natural way of operating.
This research builds on growing evidence that the metabolic switch in failing hearts might be a problem worth fixing. Previous studies suggested that heart failure involves this shift from fat to glucose metabolism, but whether fixing this switch could improve heart function was unclear. This study provides the first evidence in a large animal model that reversing the metabolic switch through diet can actually improve heart pumping ability. The findings align with emerging research suggesting that metabolic interventions might complement traditional heart failure treatments.
Several important limitations should be noted: First, this study was conducted in pigs, not humans, so results may not directly apply to people. Second, the sample size was small (only 19 animals), which limits how confident we can be in the findings. Third, the study only lasted two months, so we don’t know if benefits persist longer or if there are long-term side effects. Fourth, the high-fat diet used (20% lard) is quite high and may not be practical or safe for humans with heart failure. Finally, this study doesn’t tell us whether the high-fat diet would work in people whose heart failure has different causes or characteristics.
The Bottom Line
Based on this early-stage animal research, there is no recommendation to change diet for people with heart failure at this time. The evidence is preliminary and comes from pigs, not humans. Current evidence-based treatments for heart failure (medications, lifestyle changes, and sometimes devices) should remain the standard approach. However, this research suggests that future clinical trials testing high-fat diets in heart failure patients may be warranted. Anyone with heart failure should continue following their cardiologist’s recommendations and discuss any dietary changes with their medical team before making them.
This research is most relevant to cardiologists and heart failure researchers who are exploring new treatment approaches. People with heart failure with reduced ejection fraction (HFrEF) might find this interesting as a potential future treatment, but should not act on it yet. The general public should be aware that this is very early research and not a proven treatment. People without heart disease do not need to change their diet based on this study.
In this pig study, improvements were seen after two months of diet change. However, if this approach were ever tested in humans, it would likely take several years of clinical trials before any benefits could be confirmed and before doctors might recommend it. Realistic expectations would be that any human application is at least 5-10 years away, pending successful clinical trials.
Want to Apply This Research?
- For users interested in monitoring heart health, track resting heart rate weekly and note any changes in shortness of breath during normal activities. These are simple markers that reflect heart function changes. Users could also log their diet composition (percentage of calories from fat, carbohydrates, and protein) to identify patterns if they’re working with their doctor on dietary modifications.
- If a user’s doctor approves dietary experimentation, the app could help track a gradual increase in healthy fat sources (like nuts, avocados, and olive oil) while monitoring how they feel. The app could send reminders to log symptoms like fatigue or exercise tolerance to help identify any changes. However, this should only be done under medical supervision.
- Establish a baseline of current symptoms and heart-related measurements (if available from medical devices). Track weekly resting heart rate, daily energy levels, and exercise tolerance. If dietary changes are made, monitor these metrics monthly to identify trends. Share data with healthcare providers during regular appointments to inform treatment decisions.
This research is preliminary animal-based science and should not be used to guide personal medical decisions. Heart failure is a serious condition requiring professional medical care. Anyone with heart failure should continue following their cardiologist’s treatment plan and discuss any dietary changes with their healthcare provider before making them. This study does not prove that high-fat diets are safe or effective for humans with heart failure. Do not attempt to self-treat heart failure with dietary changes without explicit approval from your medical team. If you experience chest pain, severe shortness of breath, or other emergency symptoms, seek immediate medical attention.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.