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

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.

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.

“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.”

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

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.

“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.”

“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.

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.”

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.”