Inc.
Weight loss improved metabolic health whether participants followed keto, Mediterranean or plant-forward diets.
A Study Found Keto, Mediterranean, and Plant-Forward Diets Cut Weight Equally. 1 Decreased Liver Fat by 67 Percent
Author: Lucia Auerbach
Finding the right diet for your individual needs can feel overwhelming. A new study from WashU Medicine might give you a bit more clarity.
On Thursday, the study was published in the peer-reviewed journal Cell Metabolism. Its findings suggest that not all diet plans are created equal in reducing the cardiometabolic health risks associated with obesity.
The randomized clinical trial looked at three commonly recommended diet plans: ketogenic, Mediterranean, and plant-forward. It found that losing weight on any of them improved overall metabolic health in adults with obesity who had both elevated blood sugar and excess fat in their livers. However, limiting carbohydrates through a keto diet offered additional health benefits for the liver and blood-sugar control.
Obesity affects approximately four in 10 Americans, most of whom are already facing metabolic health risks like insulin resistance and fat buildup in the liver. When these conditions are left untreated, it can lead to type 2 diabetes, chronic liver disease, and cardiovascular issues.
Typically, weight loss is the gold standard for reducing obesity-related health risks. But it has not always been clear as to what kind of diet works best to improve metabolic health.
“There’s a lot of, let’s call it, diet nihilism among both people and clinicians, and this general sense that the best diet is the one you can stick to,” Max C. Petersen, an assistant professor of medicine at WashU Medicine and the study’s first author, told Inc. With that in mind, these researchers wanted to see what would happen when adherence to a specific diet was strictly controlled.
The team at WashU randomly assigned 55 adults with metabolically unhealthy obesity—meaning obesity with prediabetes and fatty liver—to strictly follow one of the three diets for five months: a low-carb, high-fat diet; a high-carb, low-fat, plant-forward diet; or a Mediterranean diet that was a balance of the two.
Notably, the participants received 100 percent of their food throughout the study. They attended weekly meetings with one of the study’s dietitians to help support adherence to the diet.
“A key strength of ours is the high adherence, which can only really be achieved in nutrition research by giving participants the food,” Petersen told Inc.
That approach let the researchers know exactly what participants were eating, allowing them to study the physiology of each diet with more rigor than trials that rely on dietary advice and counseling alone.
Participants across all three groups lost an equal amount of weight. They dropped roughly 10 percent of their total starting weight while boosting insulin sensitivity in muscle cells by 50 percent from baseline.
The difference for liver health
However, while there were consistencies across the three diets, the researchers found that sensitivity to insulin in liver cells improved by a factor of three on a keto diet when compared with the others.
Additionally, the keto diet reduced fat in the liver by 67 percent, compared with 45 percent among the other two diets during the five-month study.
“Fatty liver disease affects about 75 percent of adults with obesity worldwide and has become the fastest-growing cause of chronic liver disease and liver cirrhosis,” Petersen told Inc. “Our study shows that for people with obesity and fatty liver disease, a low-carbohydrate ketogenic diet could help reduce that statistic.”
The keto diet also delivered better blood-sugar control. It lowered 24-hour blood glucose by 20 percent from baseline. The other diets cut it by just 8 percent.
Additionally, it lowered daily insulin levels by 74 percent. In comparison, the Mediterranean diet lowered them by 44 percent and the high-carb plan by 27 percent. Half of the low-carb participants even reversed their prediabetes. That figure was 29 percent on the Mediterranean diet and 7 percent on the high-carb diet.
Still, the researchers cautioned that the findings apply to a specific group of adults with obesity, prediabetes, and fatty liver. It isn’t yet clear whether people without those metabolic problems would see the same benefits.
“Weight loss, even just a moderate amount, is universally beneficial in people who are metabolically unhealthy,” Petersen said. “But our results show that choice of diet remains important because it has an impact on specific health outcomes that go beyond weight loss alone.”
With subsequent research, the team hopes to understand why weight loss delivers these metabolic benefits, including the role of GLP-1 drugs. For now, the best diet may still be the one you can stick to. But for a struggling liver, cutting carbs appears to offer something extra.
Credits: TCA, LLC.