New report says worst heart-healthy diets include keto, Paleo diets

The American Heart Association released a report Thursday that ranked the top 10 diets according to their guidelines for heart-healthy eating. Researchers found that some of the most popular diets – like keto and Paleo -- ranked lower for heart health.

Nutritionist Maya Feller spoke to “Good Morning America” about the results of the study and what heart-healthy habits to keep in mind.

Feller said that researchers used the American Heart Association (AHA) criteria for heart-healthy eating patterns as the basis of the rating system, which includes nutrition requirements based on limited fat, saturated fats, cholesterol, trans fat or sodium.

"What they found was that these diets that were very low in carbohydrates like Atkins or diets that were very high in fat like keto actually scored lower," Feller explained. "In the short term, there was some weight loss and there was some improvement in lipids as well as blood sugar. However, in the long term, it really can raise the risk for LDL [or] high cholesterol. That's the bad cholesterol and that is a risk factor for heart disease."

The very low carbohydrate diets and high-fat diets, like the ketogenic and Paleolithic diets, scored the lowest on the AHA scale.

“Restrictions on fruits, whole grains and legumes may result in reduced fiber intake. Additionally, 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 AHA said in a statement.

The report also took other factors into consideration like diet flexibility, cultural relevance, personal preference and affordability.

The DASH diet, Mediterranean diet, pescatarian diet and vegetarian diet were among the top-scoring diets. The first two diets aid in managing hypertension, a known risk for heart disease.

"What we see when we're looking at the top rated diets is there's tons and tons of seafood. There's legumes, there's really nice carbohydrates, ones that have fiber," Feller noted. "Across the board, we see these patterns of eating that are really rich in fruits, vegetables, lean proteins, as the way to think about bolstering your cardiovascular health."

The AHA’s top-ranked diets often include vegetables, seafood, lean proteins, nuts, seeds and potassium-rich foods.

While people do not have to cut carbohydrates and fats completely out of their diet, Feller said that the best course of action is finding a pattern of eating that works best for the individual while just staying mindful.

“Carbohydrate literacy is key. We need carbohydrates as fuel and energy for our brain,” she said. “In terms of fat, replacing saturated and synthetic fats with mono and polyunsaturated fatty acids found in nuts, seeds and some fruits like olive and avocado can be a heart-healthy choice.”