The ten styles of diets included:
- DASH-style — describes an eating pattern that’s like the Dietary Approaches to Stop Hypertension (DASH) diet, emphasizing vegetables, fruits, whole grains, legumes, nuts and seeds, and low-fat dairy and includes lean meats and poultry, fish and non-tropical oils. The Nordic and Baltic diets are other types of this eating pattern.
- Mediterranean-style — also known as the Mediterranean diet, this pattern limits dairy; emphasizes vegetables, fruit, whole grains, legumes, nuts and seeds, fatty fish and extra virgin olive oil; and includes moderate drinking of red wine.
- Vegetarian-style/Pescatarian — a plant-based eating pattern that includes fish.
- Vegetarian-style/Ovo/Lacto — plant-based eating patterns that include eggs (ovo-vegetarian), dairy products (lacto-vegetarian) or both (ovo-lacto vegetarian).
- Vegetarian-style/Vegan — a plant-based eating pattern that includes no animal products.
- Low-fat — a diet that limits fat intake to less than 30% of total calories, including the Volumetrics eating plan and the Therapeutic Lifestyle Change (TLC) plan.
- Very low-fat — a diet that limits fat intake to less than 10% of total calories, including Ornish, Esselstyn, Pritikin, McDougal, Physicians Committee for Responsible Medicine (PCRM) diets. Some may also be considered vegan.
- Low-carbohydrate — a diet that limits carbohydrates to 30-40% of total calorie intake, and includes South Beach, Zone diet and low glycemic index diets.
- Paleolithic or PALEO — also called the Paleo diet, it excludes whole and refined grains, legumes, oils and dairy.
- Very low-carbohydrate/ketogenic or KETO — limits carbohydrate intake to less than 10% of daily calories and includes Atkins, ketogenic and the Well-Formulated Ketogenic diets.
The diets that rated the best for improving cardiometabolic health included the DASH-style eating plan, the Mediterranean diet, pescatarian and vegetarian.
The DASH-style eating plan, which stands for “Dietary Approaches to Stop Hypertension,” received a perfect score from the analysis thanks to its emphasis on being low in salt, added sugar, alcohol, tropical oils and processed foods as well as being rich in non-starchy vegetables, fruits, whole grains and legumes. Protien also tends to be mostly from plant sources along with fish, lean meats and low- or fat-free dairy products.
The Mediterranean diet, patterned on the traditional cuisines of the region, emphasizes fresh fruits and vegetables, fish, legumes, nuts and whole grains. It ranked below DASH since it doesn’t “explicitly address added salt and includes moderate alcohol consumption (rather than avoiding or limiting alcohol),” the statement explained.
Vegan and vegetarian diets were rated in Tier 2 in terms of consistency with the AHA dietary guidelines with the comments that “Strengths of these 2 dietary patterns include an emphasis on vegetables, fruits, whole grains, legumes, and, in the case of vegan diets, nuts. Moreover, they also emphasize low in-take of foods and beverages with added sugar and limited alcohol, which align with the features of a heart-healthy diet”
Lower down were very low-fat diets (Esselstyn etc) in Tier 3.
Meanwhile, paleo and ketogenic diets were found to contradict the association’s guidance and did not rank as heart-healthy eating patterns while they were assigned to Tier 4, the least consistent with heart health.
One of the study’s authors commented on the very low scores for heart health for the ketogenic (low-carb) and Paleo diets.
While short-term improvements in body weight and blood sugar have been shown with paleolithic and low-carb ketogenic-type diets in the short term, these ranked as the worst options for heart health due to high fat levels as well as restrictions on fruits, whole grains and legumes, which can result in reduced fiber intake.
“These diets are high in fat without limiting saturated fat. Consuming high levels of saturated fat and low levels of fiber are both linked to the development of cardiovascular disease,” the statement added.
They also heavily restrict carbohydrates, the body’s main fuel source.
“When you restrict total carbohydrate intake to less than 10% of calories, you miss opportunities to consume some of the micronutrients like potassium and calcium that are associated with reduced blood pressure, you reduce total fiber intake, which is also associated with better cholesterol management and you miss out on opportunities to consume a lot of plant based foods that are rich in these phytochemicals that have heart protective benefits,” Maya Vadiveloo, assistant professor of nutrition and food science at the University of Rhode Island and co-author of the statement, told CBS News Friday.
Plus, from a behavioral standpoint, these patterns tend to be very restrictive, making them difficult to maintain.