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• Eating a healthy diet is a known way to help keep a person’s heart healthy and lower their risk for cardiovascular disease.
• There is already evidence that certain diets, such as the Mediterranean diet, can help protect heart health.
• Researchers at the University of Southern California have now found that the fasting-mimicking diet provides some unique heart-healthy effects when compared to the Mediterranean diet.

Following a healthy diet is a known way to help keep the heart healthy and lower the risk of cardiovascular disease.

Previous research has shown that diets like the Mediterranean diet, Paleo diet, DASH diet, and plant-based diets may provide some cardiovascular benefits.

Now, a new study from researchers at the University of Southern California has found that the fasting-mimicking diet provides some unique heart-healthy effects when compared to the Mediterranean diet.

The study was recently published in the journal Npj Metabolic Health and Disease.

What is the fasting-mimicking diet? 

According to Dr. Valter D. Longo, Edna M. Jones Chair in Gerontology and professor of gerontology and biological sciences at the USC Leonard David School of Gerontology at the University of Southern California, lead author of this study, the fasting-mimicking diet is a 5-day vegan diet with a composition such that the human body responds as it does to water-only fasting.

“For the rest of the month, the patients [return] to their normal diet,” Dr. Longo — who developed the fasting-mimicking diet — explained to Medical News Today.

The 5 days of the fasting-mimicking diet focus on low-calorie, low-protein, and high-fat plant-based foods.

Unlike intermittent fasting, a person on the fasting-mimicking diet continues to eat during the “fasting” period.

Over the last few years, researchers have been examining the use of the fasting-mimicking diet in cancer treatment to help potentially slow down the growth of tumors, and make them more susceptible to chemotherapy in certain types of cancer, such as colorectal cancer.

Researchers have also looked at how the fasting-mimicking diet might improve breast cancer therapy in people with hormone-receptor-positive breast cancer.

Additional studies have looked at using the fasting-mimicking diet in the treatment of conditions such as multiple sclerosis (MS), cardiometabolic disease, autoimmune diseases, inflammatory bowel disease (IBD), skin issues, and Alzheimer’s disease.

Fasting-mimicking vs Mediterranean diet

Dr. Longo said they decided to compare the effectiveness of the fasting-mimicking diet in reducing the risk for cardiovascular disease among adults with obesity and hypertension against the Mediterranean diet for in part because most people have difficulty changing their diet.

“Even in the Mediterranean area, [the Mediterranean diet] is not followed by most people in those countries,” Dr. Longo continued.

In previous research, Dr. Longo’s team found that a similar fasting-mimicking diet was effective in reversing virtually all of the negative effects of a high-calorie Western diet on cholesterol, blood glucose, heart function, and lifespan in mice.

“Thus, a 5-day diet that comes in a box like medicine could allow people that don’t want to change [their] diet [to] have the benefits of a healthier diet potentially if done less than once a month,” he told us. “We believe that 15–20 days a year could already provide important benefits.”

Reduction in blood pressure measurements

For this study, Dr. Longo and his team recruited 84 study participants, including both men and women, between the ages of 35 to 75.

Study participants all had a body mass index (BMI) of or above 28, which some experts consider to be an indicator of overweight or obesity. Scientists also evaluated study participants’ reactive hyperemia index (RHI) and scores on small and large arterial compliance (AC1/AC2), both of which help measure blood pressure.

For 4 months, about half of the participant pool followed the fasting-mimicking diet, while the other half followed the Mediterranean diet.

Upon analysis, researchers found those in the fasting-mimicking diet group experienced a reduction in their RHI.

“A lower reactive hyperemia is observed in subjects with reduced heart function but also in younger, healthier, and normal subjects,” Dr. Longo explained.

“Because all other markers are evidence of rejuvenating effects of the fasting-mimicking diet, we believe this reduction in reactive hyperemia is consistent with rejuvenation of the heart, but larger studies are needed to establish this.”

– Dr. Valter D. Longo

Scientists reported neither diet group saw any improvements in AC1/AC2 measures or changes in abnormal RHI.

Decrease in biological age markers, abdominal fat 

The study also showed that participants in the fasting-mimicking diet group sustained reductions in their biological age, heart age, and their Protein Unstable Lesion Signature (PULS) cardiac test scores, which evaluate a person’s 5-year risk of stroke, compared to the Mediterranean diet group.

Fasting-mimicking diet participants showed a marked decrease in trunk fat mass — fat collected around the abdomen — compared to the Mediterranean group.

Additionally, the fasting-mimicking group did not show a decline in lean muscle mass at the end of the study’s follow-up period. Researchers found that those in the Mediterranean diet group experienced a loss of lean muscle mass.

“The significance is that fasting-mimicking diet cycles were able to decrease fat mass without reducing muscle mass and without requiring changes in the subjects’ preferred diet for 25 days a month,” Dr. Longo said. “In contrast, the everyday Mediterranean diet required [a] change in everyday dietary habits and was associated with a 5 [pounds] loss of muscle.”

Encouraging findings with more research needed

After reviewing this study, Dr. Rigved Tadwalkar, a board-certified cardiologist at Providence Saint John’s Health Center in Santa Monica, CA, not involved in the research, told MNT he found the findings encouraging.

“When we look at different sorts of diets, we really want to get down to what sort of health benefit they actually provide,” Dr. Tadwalkar explained.

“It was nice to see that both the fasting-mimicking diet and Mediterranean diet — which is almost like the mainstay of recommended diets right now — both led to weight loss and improvements in blood pressure, cholesterol, [and] blood sugar. These are all very important cardiometabolic parameters that lead to cardiovascular disease, so it’s nice to see that both are able to do so.”

– Dr. Rigved Tadwalkar

“What was interesting about the fasting-mimicking diet is that it had the added benefit of reducing abdominal fat, which was really important because that is a big reason why a lot of people diet,” he continued. “Not to mention it’s still important even from a medical standpoint because abdominal fat is a risk factor for cardiovascular disease.”

Dr. Tadwalkar also commented that just over the last few weeks, he has had many patients concerned about certain diets leading to lowered lean body mass.

“It looked like in the fasting-mimicking diet group versus the Mediterranean diet group they did not experience any loss of that lean body mass, which could be a concern for some other weight loss intervention,” he added.

However, Dr. Tadwalkar said while this study was able to delineate the short-term effects of the fasting-mimicking diet, having the longer-term effects observed over weeks, months, and years is required for better understanding.

“And how the fasting-mimicking diet really affects cardiovascular health in the long-term, and in delaying the onset of cardiovascular disease,” he added.

Tips for finding the best heart-healthy diet

MNT also spoke with Monique Richard, a registered dietitian nutritionist, owner of Nutrition-In-Sight, and national media spokesperson for the Academy of Nutrition Dietetics, about this study.

Richard commented that this study adds to our knowledge that each individual’s needs are unique and that our body’s complex and intricate interaction with nutrients is multifactorial.

“Following a fasting-mimicking diet has been beneficial for many individuals but it is neither a ‘stand-alone’ solution nor a long-term alternative,” she continued. “Changing patterns, habits, and/or an accumulation of the consequences of [a] specific behavior or genetic predisposition is a process that cannot be reversed with one specific step. However, several intentional modifications can make significant changes over time.”

“Foods that are high in vitamins, minerals, and phytochemicals will not only provide necessary nutrients but counter inflammation, interruption, and degradation of systems that support heart health,” Richard added. “These foods include fruits, vegetables, legumes, nuts, seeds, plant fats, lean proteins, fermented foods, and whole grains. Understanding the ‘hows’ is key — how much, how to prepare, and how often.”

And while finding the best diet for losing weight and heart health can be overwhelming at times, Richard said finding a dietary pattern and lifestyle that is most conducive to a person’s unique needs is imperative.

“A registered dietitian nutritionist (RDN) is trained to understand the interplay among medical conditions, cardiometabolic markers, genetics, preferences, needs, lifestyle factors — activity, access, cultural traditions, etc. — cooking literacy, gut health, and more to be able to offer specific recommendations,” she advised. “Work with a professional to mitigate confusion and garner support in a health-seeking journey that works best for you.”