To evaluate the quality of the diets, the foods people ate were classified into 18 groups: whole grains, fruits, vegetables, nuts, legumes, vegetable oils, tea and coffee, fruit juices, refined grains, potatoes, sugar-sweetened beverages, sweets and desserts, animal fat, dairy, egg, fish or seafood, meat and miscellaneous animal-based foods.
The preliminary data shows that people in the lowest-carb group who got more of their protein and fat from plant-based sources had a 6 percent lower Type 2 diabetes risk — and if their eating further minimized sugar and other refined carbohydrates, they had a 15 percent lower risk. By contrast, the lowest-carb group eating diets emphasizing animal protein and fat had a 35 percent higher risk of Type 2 diabetes — and a 39 percent higher risk if their diets also minimized whole grains.
Wang said one weakness of the study was that most of the people in it were white.
“We wonder whether our results could be generalized to other ethnic groups,” she said. “We need to look at that, as well as people who consistently consumed very low-carb diets, such as the keto diet.”
The American Heart Association recommends eating a diet that includes a wide variety of fruits and vegetables and healthy sources of protein, such as fish and seafood, legumes and nuts, low-fat or nonfat dairy and lean meats. It encourages choosing minimally processed foods over ultra-processed foods, and limiting sugar, salt and alcohol.