The ketogenic diet—a weight-loss diet that is traditionally high in animal protein—has been named the least-healthy diet of the year by a panel of diet and nutrition experts in the US News and World Report annual diet rankings. The experts rated 40 diets on a range of levels, including weight loss, nutrition, safety, and their ability to prevent and manage heart disease and diabetes. After scoring each diet, the experts constructed nine Best Diet categories, including Best Weight Loss Diets, Best Heart Healthy Diets, and Best Diets Overall.
In the Best Diets for Healthy Eating category, keto ranked lowest—and very close to the bottom of the list in all other categories except Best Fast Weight-Loss Diets. In addition to being “extremely incomplete” in nutrition and “the hardest of the extremely hard” in terms of ease of following, experts had particular concerns about the keto diet’s high saturated fat content. “Any diet that recommends snacking on bacon can’t be taken seriously as a health-promoting way to eat,” one expert said. Another pointed out that the keto diet is “nutritionally unbalanced and likely difficult for most people to stick with long-term, which means that any weight loss will likely be regained.”
The keto diet also ranked lowest because it poses health risks, particularly for people with certain medical conditions. People who have kidney or liver conditions, or are pregnant or nursing, underweight, or have heart disease should avoid the diet, the experts warned.
“With its combination of unusually high fat plus remarkably low carb content, experts had enough reservations to place the keto diet way down in [the nutrition] category. Experts expressed particular concern for people with liver or kidney conditions, who should avoid it altogether,” the ranking noted. “The jury is still out [on] whether keto offers more potential health risks or benefits for people with heart conditions or diabetes. With the variety of keto versions and food choices, and different methods for cycling in and out of the diet, hormonal and other changes can vary widely.”
Keto diet ranks worst. Is a plant-based diet best?
Overall, the diet rankings put the Mediterranean diet at the top of the list in both overall and healthy eating categories for its emphasis on fruits, vegetables, whole grains, beans, nuts, and other healthy fare—similar to a healthy plant-based eating plan, although the Mediterranean diet includes seafood and dairy in moderation. It also scored top spot because it’s easy to follow and experts point out that it emphasizes healthy foods rather than a list of diet rules.
Meanwhile, the vegan diet ranked #17 in Best Diets Overall. The experts who weighed in on the rankings pointed out that the diet is filling because it’s rich in high-fiber foods and has both health and environmental benefits, but it can be a lot of work due to added at-home meal preparation. The experts also note that if the individual doesn’t follow a sensible plan, they could miss out on important nutrients.
“While eating a healthy vegan diet does require some planning, in recent years there’s been a rise in vegan alternatives to animal products well beyond the familiar staples of tofu and soy, such as oat milk, nut cheeses, tahini shakes, seaweed bacon, and pea protein burgers,” the ranking noted.
What’s also notable is that the vegan diet received top scores in Best Diets for Diabetes (#2) and in Best Heart-Healthy Diets (#4). The experts noted research that found that a vegan diet improves blood sugar levels and helps diabetics reduce the number of medications they are taking. Research also suggests that the diet helps keep cholesterol and blood pressure in check and heart disease at bay.
The long-term consequences of keto
While the Mediterranean and vegan diets are more likely to become lifestyles, the keto diet has the allure of many other fad diets that promise quick weight loss, but it also includes numerous health risks. A study published last year in scientific journal Frontiers in Nutrition found that the long-term consequences of a keto diet may far outweigh any potential short-term benefits such as quick weight loss.
The published review found that people who follow a keto diet have a significantly increased risk of developing heart disease, LDL cholesterol buildup, kidney failure, Alzheimer’s disease, diabetes, and cancer. Similar to the information included in the US News and World Report annual diet rankings, the 2021 study’s authors discovered that keto diets are particularly dangerous for people who are pregnant or may become pregnant—because low-carb diets are linked to birth defects—and for those living with chronic kidney disease.