Which is better: a low-fat vegan diet or a Mediterranean diet?

For the fourth consecutive year the Mediterranean diet has been ranked the best overall diet by US News. Besides its overall health benefits, it is often cited as one of the friendliest diets to follow and therefore most likely to be continued long term. One of the disadvantages is the broad interpretation of what a Mediterranean diet is, frequently leading to excessive consumption of olive oil, fatty fish or refined carbohydrates such as pasta.  

A recent publication in the Journal of the American College of Nutrition (Feb. 2021) presents the results of the first randomized direct comparison between the Mediterranean diet and a low-fat vegan diet. In the study 62 overweight adults (BMI 28-40) on a standard Western diet were randomized to a Mediterranean or vegan diet for 16 weeks. After a return to their baseline diet for 4 weeks they were placed on the opposite diet for 16 weeks. There were no calorie restrictions, change in exercise routines or medications (unless by primary care physicians).  

After the 16-week period on each diet average weight loss was 6 kg (13.2 lbs.) on the vegan diet while there was no weight loss on the Mediterranean diet (see figure). This weight loss consisted of more fat mass loss (3.4 kg; 7.5 lbs.) and visceral fat loss 315 cm3, which is a key issue with metabolic syndrome.  


In addition to weight, and specifically fat loss, the vegan diet decreased total and LDL-cholesterol significantly more than the Mediterranean diet.  

Measures of fasting insulin resistance and post prandial insulin sensitivity were both favorably and significantly altered on the vegan diet, while there was no change on the Mediterranean diet.  

Blood pressure was reduced on both diets, however, there was a greater reduction on the Mediterranean diet compared to the vegan diet (6.0 vs 3.2 mmHg). 

Although there was no restriction in caloric intake in either group, weight loss with the vegan diet is attributed to fewer calories consumed because of the reduction in fat calories and the high fiber content, which leads to decreased caloric density.  

The improved insulin sensitivity with the vegan diet is related to lipotoxicity, the effect that fats have on the insulin receptor. In other words, the low-fat content of a plant-based diet is protective against Type 2 diabetes.  

There are many studies demonstrating that individuals who adopt a plant-based lifestyle do have a high probability of staying with it and the drop off rate is quite low. This is despite the poor support received from the medical community which is beholden to medications for treatment of chronic diseases. In addition, many “plant-based” diets are not necessarily healthy as heavily processed foods contain a lot of sugar and fat. This is especially true of a lot of the meat substitutes that are heavily advertised and receive a lot of publicity. 

We at Plant Street see a huge need for education and support to those who choose to live healthy rather than take medications and suffer from chronic diseases.  





“The aging process unfortunately doesn’t have a brake; we can’t stop it. It just has an accelerator, and our life expectancy is dependent upon how hard we step on it.”  Anon 


Author: Henri P. Lanctin, MD FACS