New Study Findings: A High Protein Diet More Effective in Improving Insulin Resistance Compared to Mediterranean Diet

Obesity can increase the risk of developing multiple health conditions and complications and is considered a pandemic. This is a major public health concern, due to the increased risk of developing cardiovascular disease, type II diabetes, and different types of cancer. 

That’s why new and better strategies to combat obesity are of utmost importance. As well as encouraging increased physical activity, many efforts to reduce obesity and its associated disorders have focused on the impact of diet and nutrition.

One of the more commonly known beneficial diets associated with improved health outcomes is the Mediterranean diet, characterized by high levels of polyphenols, mono and polyunsaturated fatty acids, antioxidants, and fiber. 

On the other hand, a high protein diet, with low carbohydrate consumption, high fat, and high protein intake has also been suggested as a potential dietary intervention for obesity prevention. 

New Study Results 

In a recent study published in the journal Nutrients, researchers evaluated the use of both the Mediterranean diet (M) and a high protein diet (HP), and which is more effective in improving insulin resistance and glycemic variability. 

The study included 20 insulin-resistant women with obesity that were randomized during a 21-day crossover controlled dietary trial. 

Participants were assigned to receive, in a 1:1 ratio, one of the two following dietary sequences: hypocaloric M diet followed by hypocaloric HP diet (sequence M–HP) or vice versa (sequence HP–M). Each period of intervention lasted 10 days with no washout before the switch from the first to the second diet.

These women were not following any specific diet in the 6 months preceding the study enrolment. The Mediterranean diet was composed of approximately 55% carbohydrates (whole wheat), 25% fat (olive oil, almonds and pistachios), and 20% protein (fish, goat cheese, and legumes). The High protein diet was composed of approximately 40% carbohydrate, 30% fat, and 30% protein. Both diets had the same caloric intake, which was 500 Kcal less than the individual daily caloric requirement, and a similar moderate glycemic load ranging between 11 and 19. 

The HP and M diets led to a similar loss of body weight, with a mean change from  baseline of -2.71 kg and 2.09 kg, respectively. Also, changes in biometric measures like BMI, waist to hip ratio, fat to lean mass ratio lipids, blood pressure, and in gut microbiome composition were similar after the 2 diets. 

According to the study results, the HP diet was more effective in reducing insulin levels, leading to a mean change from baseline of -3.5 µIU/mL, while higher levels were registered after the M diet with a value of 1.55. The reduction in glucose concentration was also slightly greater in the HP diet.

The researchers also saw a lower glycemic variability following the HP diet. Glucose variability is a risk factor for type II diabetes development and complications, and increases in variability may be considered an additional parameter in the assessment of glucose homeostasis.


Tettamanzi F, Bagnardi V, Louca P, et al. A High Protein Diet Is More Effective in Improving Insulin Resistance and Glycemic Variability Compared to a Mediterranean Diet-A Cross-Over Controlled Inpatient Dietary Study. Nutrients. 2021;13(12):4380. Published 2021 Dec 7. doi:10.3390/nu13124380

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