You don’t need to be a nutritionist to know that there’s a dietary war going on in US culture.
But in the world of heart health, there’s a very clear winner: whole, real foods with as few carbohydrates as possible.
This leads many people to start with the Mediterranean diet, which is popular among those just beginning their heart health journey. However, research sheds some light on how it compares to lower-carb diets such as keto.
And in the scientists’ words: “A very low-carbohydrate ketogenic diet has greater cardiometabolic benefits [than matched Mediterranean and plant-based low-fat diets].”
Let me show you the evidence so you can come to your own conclusions.
Article overview
- Mediterranean diets emphasize whole, real carbs and limited animal protein, while keto advocates for a high-fat, high-protein diet.
- In a controlled trial comparing the Mediterranean diet vs keto diet in participants with obesity, prediabetes and fatty liver disease, keto performs better in terms of biomarkers and insulin resistance.
- This is because keto diets rely on much lower-carb diets than traditional Mediterranean diets.
First: a quick overview of each diet
Before we dive into the particulars of each diet, it would be helpful to explain what falls under each category.
The Mediterranean diet, as the name suggests, was designed to emulate the eating styles of classical-era Mediterranean peoples. The early Greeks and Romans, for example, ate a great deal of goat and sheep cheese, vegetables, olive oil, and fish/seafood. The idea is to eat as little processed food as possible, eat eggs and lean meats weekly, while limiting beef and red meat to a few times a month.
But apart from its highly plant-centric style of eating, the Mediterranean diet can also be fairly low-fat. Instead of whole, full-fat yogurt or raw milk, for example, you might swap for almond milk and fat-free yogurt. It also encourages people to eat whole, real grains. For example, you might eat plenty of quinoa and barley, or chia seeds, since they’re not as processed as options like white rice and quick oats.
Note that the Mediterranean diet does not refer to ‘Italian food,’ which in a modern context can range anywhere from pizza and spaghetti to fettuccine alfredo. The goal is eating more whole, real food and low-fat meals.
The keto diet, on the other hand, emphasizes an extremely low-carbohydrate lifestyle. Your goal should be to eat high-fat meals and limit carbohydrates to a certain percentage or gram amount per day. This means getting plenty of saturated fat from red meat, butter, tallow, and more.
Unlike the carnivore or lion diet, greens are often a staple of the keto diet. The biggest difference is in avoiding high-carb vegetables such as potatoes, onions, and corn. In fact, most of the calories on this diet come from animal protein, seafood, and eggs.
That said, it’s hard to select a defined set of macros for either ketogenic or Mediterranean diets. So for the purposes of this discussion, I’ll set the macros like this:
| Macronutrient | Very-low-carb ketogenic | Mediterranean |
| Carbohydrate | 20 g (4%) | 254 g (50%) |
| Protein | 112 g (23%) | 83 g (15%) |
| Fat | 164 g (73%) | 80 g (35%) |
These are also the macros used in the clinical trial I want to investigate with you today.
How the keto diet performs against the Mediterranean diet
https://twitter.com/nicknorwitz/status/2095126342702358834
Both the keto diet and the Mediterranean diet focus largely on unprocessed foods. This, compared to the Standard American Diet, will almost always result in better metabolic health outcomes.
But in a study comparing keto vs Mediterranean head-to-head, the ketogenic diet was far and away the superior option for heart health.
To summarize it quickly: researchers studied 55 participants who were diagnosed with metabolically unhealthy obesity (i.e., obesity with prediabetes and fatty liver disease). They assigned groups of participants to follow a specific diet, with calorie intakes adjusted to ensure all three groups would lose 10% of their body weight.
As expected, the participants lost approximately 10% of their body weight. But contrary to most popular narratives, the Mediterranean diet didn’t produce the best possible heart health results.
Keto did.
Now, keep in mind that a plant-based, low-fat diet was also included in this study. I’ll refer to a few of the findings for this, but by and large, it performed the worst of the three in terms of biomarker outcomes.
You can learn more about the problems of plant-based diets here. Then, learn more about how to eat metabolically healthy with five different popular diets.
I also want to highlight an important point of nuance from this study: the participants were very metabolically unhealthy, and so we’d expect to see a large impact from carbohydrate restriction. This isn’t to suggest that identical results would be seen in participants who are lean and metabolically healthy.
With that out of the way, let me break down the two biggest differences in the keto and Mediterranean diet’s outcomes:
Better biomarkers
First: researchers found that the ketogenic diet produced greater reductions in:
These are all causes and effects of heart disease, and critical to manage for a longer healthspan.
Improved insulin resistance scores (LP-IR)
Second: let’s talk about insulin resistance scores.
All three diet types included in this study helped to reduce insulin resistance scores by some degree. But the low-fat diet only improved the metric by three points. The Mediterranean diet more than doubled this, with a seven-point improvement. But the keto diet tripled this with a 21-point improvement.
Why a lower-carb approach works better for the heart
The Mediterranean diet and keto diet are similar in many ways: they both emphasize cooking at home, avoiding processed food, and opting for whole, real food alternatives. This, in my mind, is an excellent place to start for reclaiming your metabolic health.
But the reason why keto pulls ahead is that it minimizes carbohydrates to a low level. It results in better insulin control, more effective blood sugar management, and better biomarkers compared to a higher-carb Mediterranean diet.
That said, the keto diet is just the tip of the iceberg. You can go lower still with carbohydrates by selecting a lion or carnivore diet.
Learn more about the benefits of low-carb diets on heart health in the following resources: