What’s New in Plant-Based Diet Research?

Every decade seems to have its fad diets. Those superlatively restrictive (and often very odd) patterns of eating that purport to allow you to drop many pounds quickly.


For example, the Lemonade Diet/Master Cleanse, featuring a lemonade containing maple syrup and cayenne pepper; the early 1980s Beverly Hills Diet, based on consuming only fruit in a specific order for the first 10 days; the infamous Grapefruit Diet where you eat a half a grapefruit with your tiny meals. Then there were the Cabbage Soup Diet, The Cookie Diet, the Hollywood 48-Hour Miracle Diet, and more. All these diets worked quickly only because dieters were restricted to approximately 500 to 800 calories a day. The problem? It is unsustainable and can lead to health issues as the body is severely deprived of energy.


At first blush, the name “plant-based diet” may also sound highly restrictive, conveying the consumption of only vegetables. But that is farthest from the truth – it simply means eating sensibly, with the majority of foods you eat coming from plants (vegetables, fruits, herbs/spices, nuts, grains) with a minor emphasis on lean meats or fish. It can also be called “flexitarian,” because a plant-based diet doesn’t mean you must give up meats, like vegetarianism.


One analysis of studies confirmed that following a plant-based diet can reduce weight and body fat in people who are overweight and obese; the study authors noted that according to the World Health Organization, approximately 2.7 billion people will be overweight or obese by 2025.


In 2021 alone, there have been several strong studies showing the benefits of a plant-based diet for a wide range of people. Eating more nutritious, plant-based foods is heart-healthy at any age, according to two studies published in the Journal of the American Heart Association. In these two separate studies analyzing different measures of plant-based diets, researchers found that both young adults and postmenopausal women had fewer heart attacks and were less likely to develop cardiovascular disease when they ate more healthy plant foods.


One long term study linked a plant-based diet during young adulthood (20s) with a reduced risk of heart disease developing in middle-age.  


The team examined diet and the occurrence of heart disease in 4,946 adults enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Participants were 18- to 30-years-old at the time of enrollment (1985-1986) in this study and were free of cardiovascular disease at that time. Participants had eight follow-up exams that included lab tests, physical measurements, medical histories, and assessment of lifestyle factors. Unlike randomized controlled trials, participants were not instructed to eat certain things and were not told their scores on the diet measures, so the researchers could collect unbiased, long-term habitual diet data.


After detailed diet history interviews, the quality of the participants diets was scored based on the A Priori Diet Quality Score (APDQS) composed of 46 food groups at years 0, 7 and 20 of the study. The food groups were classified into beneficial foods (such as fruits, vegetables, beans, nuts and whole grains); adverse foods (eg, fried potatoes, high-fat red meat, salty snacks, pastries and soft drinks); and neutral foods (such as potatoes, refined grains, lean meats and shellfish).


Participants who received higher scores ate a variety of beneficial foods, while people who had lower scores ate more adverse foods. Overall, higher values correspond to a nutritionally rich, plant-centered diet.


Analyzing the 32 years of the study data, researchers found:

  • 289 of the participants developed cardiovascular disease (including heart attack, stroke, heart failure, heart-related chest pain or clogged arteries anywhere in the body).
  • People who scored in the top 20% on the long-term diet quality score (meaning they ate the most nutritionally rich plant foods and fewer adversely rated animal products) were 52% less likely to develop cardiovascular disease, 
  • Between years 7 and 20 when participants ages ranged from 25 to 50, those who improved their diet quality the most (eating more beneficial plant foods and fewer adversely rated animal products) were 61% less likely to develop subsequent cardiovascular disease, in comparison to the participants whose diet quality declined the most during that time.


In another study, researchers evaluated if a diet that included plant-based foods that have FDA-approved health claims for lowering "bad" cholesterol levels (known as the "Portfolio Diet") were associated with fewer cardiovascular disease events in postmenopausal women.


The study included 123,330 women who participated in the long-term national Women's Health Initiative, who enrolled in the study between 1993 and 1998, and were between 50-79 years old without cardiovascular disease. The study group was followed until 2017. 


The researchers found that compared to women who followed the Portfolio Diet less frequently, those with the closest alignment were 11% less likely to develop any type of cardiovascular disease, 14% less likely to develop coronary heart disease and 17% less likely to develop heart failure. The researchers concluded that “an 11% reduction is clinically meaningful and would meet anyone's minimum threshold for a benefit. The results indicate the Portfolio Diet yields heart-health benefits.”


Meanwhile, in a systematic review and meta-analysis of how plant-based diets affected cardiometabolic risk, researchers looked at associations with type 2 diabetes as well as cardiovascular disease outcome in 10 studies. They found that those individuals who adhered to a diet rich in plants had reduced incidence of development of type 2 diabetes and cardiovascular disease compared to those who consumed the least amount of plant-based foods. 


One measure of cardiometabolic fitness (or lack thereof) is blood glucose levels. In a review of 11 studies looked at the relationship between plant-based eating and diabetes biomarkers such as A1c, insulin sensitivity and fasting blood glucose. They also compared this with other diets such as conventional, DASH, Mediterranean and low-carbohydrate. According to the authors, the results suggest that a plant-based diet is linked to improved hemoglobin A1c, as well as improved fasting blood glucose. 


On a larger scale, another team evaluated the associations between changes in plant-based diets and risk of developing type 2 diabetes .The researchers  followed 76,530 women in the Nurses’ Health Study (NHS) (1986–2012), 81,569 women in NHS II (1991–2017), and 34,468 men in the Health Professionals Follow-up Study (1986–2016). Adherence to plant-based diets was assessed every 4 years.


We documented 12,627 cases of type 2 diabetes during follow-up. After adjustments, they found that those who had the largest reductions their plant-based consumption for initial BMI and initial and 4-year changes in alcohol intake, smoking, physical in a four-year period had a 12 to 23% higher risk of developing type 2 diabetes in the subsequent four years.


The researchers concluded that “adherence to overall and healthful plant-based diets was associated with a lower risk of type 2 diabetes, whereas decreased adherence to such diets was associated with a higher risk.”




Researcher Yuni Choi of the Department of Food Science and Nutrition of the University of Minnesota stated, " A plant-centered diet is not necessarily vegetarian. People can choose among plant foods that are as close to natural as possible, not highly processed. We think that individuals can include animal products in moderation from time to time, such as non-fried poultry, non-fried fish, eggs and low-fat dairy."

There’s just no getting around it – the healthier you eat, the healthier you will age! 

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