Mediterranean Diet vs. Keto Diet: Which Is Healthiest?

Pictured Recipe: Mediterranean Chickpea Quinoa Bowl

One promotes meat and cheese; the other pushes plants. Can two vastly different diets both be healthy? Ahead, we take a deep dive into what the research says about the Mediterranean diet versus the keto diet.

The Mediterranean diet and the keto diet have both been around for decades, but new health claims are always popping up about both diets. We summarize the pros and cons of each, discuss which foods are and aren't allowed, and explain (and debunk) the reported health benefits associated with adhering to each style of eating.

What Is the Mediterranean Diet?

The Mediterranean diet is more of a lifestyle than a diet. Its name is a reference to the traditional eating pattern of people living in countries bordering the Mediterranean Sea. Although people in countries like Italy and Greece have been eating this way for centuries, the Mediterranean "diet" wasn't popularized until the 1960s, when a group of researchers noted that people in that area of the world were exceptionally healthy and had a lower risk of many lifestyle diseases compared to Americans.

So what does the Mediterranean diet look like? It includes an abundance of fruits, vegetables, whole grains, beans, legumes and healthy fats; a moderate amount of chicken, fish, eggs and dairy; and limited amounts of red and processed meats, added sugars and processed foods. Any foods fitting these categories fit into a Mediterranean diet; the health benefits are not exclusive to the specific foods found around the Mediterranean. Enjoying meals with others, having an occasional glass of red wine and being physically active most days are also components of the Mediterranean diet.

Mediterranean Diet Drawbacks

Because the Mediterranean diet is so liberal, the lack of structure may make it challenging for some people to follow. The current Dietary Guidelines for Americans include a Healthy Mediterranean-Style Eating Pattern to address this, which provides serving size and calorie count estimates. Another potential downside of the Mediterranean diet is that it may be time-consuming to prepare meals and potentially expensive, although arguably no more time-consuming or expensive than the keto diet. Plus, you can absolutely incorporate frozen and canned produce and dried herbs and spices if that's helpful to reduce food waste and prep time.

Mediterranean Diet Benefits

On the flip side, the lack of structure in the Mediterranean diet is a pro for many. There are no restrictions and no calorie counting. It's simply about eating more of some foods and less of others. That often makes it much easier for people to adhere to than a hugely restrictive diet that may not be manageable in the long term. Not to mention, it's been named the healthiest overall diet by U.S. News & World Report for five years running! That's pretty tough to beat, if you ask us.

A Mediterranean Diet Menu That Shows How to Put This Plan into Practice

To help you visualize a day in the life, here's a peek at a sample menu for the Mediterranean diet.

• Breakfast: Baked Eggs in Tomato Sauce with Kale
• Lunch: Greek-Style Meatball Mezze Bowls
• Snack: Peanut Butter and Chia Berry Jam English Muffin
• Dinner: Salmon Rice Bowl
• Dessert: Strawberry-Chocolate Greek Yogurt Bark

What Is the Keto Diet?

The ketogenic ("keto") diet was developed in the 1920s as a treatment for epilepsy. It's a high-fat, moderate-protein, low-carbohydrate diet that has since been analyzed for weight loss, diabetes, cancer, Alzheimer's disease and more. The keto diet is characterized by a very low carbohydrate intake, with less than 5% of all calories coming from carbs. When carbohydrate intake is extremely low, the body begins to break down fat for energy through a process called ketosis. The liver turns fat into ketones, which are used for energy until you start eating carbs again.

The main foods that make up a keto diet include meat, fish, cheese, eggs, oils, avocados, butter, cream, nuts, seeds and low-carb vegetables. Higher-carb vegetables, most dairy, grains, beans, fruit and processed foods are limited or eliminated since they drive up carb intake—and potentially shift the body out of ketosis.

Keto Diet Drawbacks

While the ketogenic diet can lead to rapid weight loss, it does have some disadvantages. As the body switches from burning carbs for fuel to burning fat for fuel, it enters ketosis, which may cause you to experience the "keto flu"—which feels a lot like the actual flu. And since the carb count is so limited, the keto diet also requires diligent planning, and may require the help of a registered dietitian or other nutrition professional to ensure you are following it correctly. Because it's a highly restrictive diet, very few people are able to eat keto forever—which may lead to gaining back some (or all) of the weight lost. Speaking of that weight loss, research suggests that the initial speedy shift on the scale is almost all "fat-free mass," or weight loss that's due to water weight or muscle loss.

Also, no one knows the long-term effects of consuming a very high-fat, low-carb diet. The Dietary Guidelines for Americans recommend eating 25% to 35% of calories from fat, 10% to 30% from protein and 45% to 65% from carbohydrates. On a ketogenic diet, 80% of daily calories are from fat, 15% to 20% are from protein and less than 5% are from carbohydrates.

Keto Diet Benefits

The keto diet may help you lose weight quickly, lower blood sugar and improve insulin sensitivity. And you don't have to count calories to do it. Eating a high-fat diet increases feelings of satiety, while increased protein contributes to weight loss by suppressing appetite and boosting metabolism (although keep in mind that adding protein to any diet will do that). Finally, it also appears to outsmart ghrelin, a hormone that tells your brain you're hungry, which typically rises when people diet and lose weight: a study in the European Journal of Clinical Nutrition found that when people followed the ketogenic diet for weight loss, ghrelin was suppressed. That's good news for people who tend to give up dieting because they feel hungry all the time. (By the way, "giving up" on dieting can be a very good thing sometimes.)

Keto Diet Recipes That Show How to Put This Plan into Practice

Here's the dish about a day in the keto diet. To follow the keto diet strictly, add more fat (such as avocado or olive oil) to breakfast and limit or eliminate the grapes from lunch.

• Breakfast: Cauliflower Hash with Sausage & Eggs
• Snack: Sicilian Marinated Olives
• Lunch: Chicken Salad-Stuffed Avocados
• Snack: Spinach & Feta-Stuffed Portobello Mushrooms
• Dinner: Grilled Short Ribs & Cherry Tomatoes with Chimichurri

What Can You Eat on the Keto Diet and the Mediterranean Diet?

Below, we've compiled a summary of what you can—and can't—eat on each of these diet plans so you can compare them head-to-head.

So Which Diet Is Healthier?

A controlled trial published in the May 2022 American Journal of Clinical Nutrition was actually conducted to answer this very question. Scientists at the Nutrition Studies Research Group at Stanford University asked 33 people with prediabetes and diabetes to follow both diets, first one and then the other, for three months each. During the first month, participants received healthy keto diet or Mediterranean diet meal deliveries, then for the next two months, they were given criteria to follow and created meals and snacks on their own.

"I tried to give each diet the best chance. I didn't try to make it a crappy keto and a good Mediterranean or a crappy Mediterranean and a good keto," study author Christopher Gardner, Ph.D., a research professor of medicine at the Stanford Prevention Research Center, tells CNN.

Both groups lost similar amounts of weight and showed better blood sugar stability, but the Mediterranean diet came out a clear winner on one very important factor: its ability to reduce LDL (low-density lipoprotein) cholesterol, aka "bad" cholesterol. Keto dieters also ate far less fiber and tended to consume lower levels of several vitamins and minerals, including thiamine, vitamins B6, C, D and E and phosphorus. The takeaway, the study authors say: There doesn't appear to be any advantage to severely restricting healthy carbs like beans, whole grains, fruits and vegetables.

The Mediterranean diet is associated with reduced risk of cardiovascular disease, diabetes, some cancers and Alzheimer's disease, according to a review published in the journal Current Opinion in Clinical Nutrition and Metabolic Care.

A diet high in omega-3 fatty acids, antioxidants and polyphenols—such as the Mediterranean diet—helps decrease chronic inflammation, and lower levels of inflammation are correlated with lower rates of obesity, heart disease, cancer and diabetes, among other conditions. (This may be part of the reason the diet is linked to better cognitive function as one ages.) Additionally, fiber from fruits, vegetables, whole grains and beans provides prebiotics, which is food for the gut bacteria that keep your microbiome healthy, thereby lowering inflammation.

Saturated and trans fats, processed foods, excessive sugar, refined carbohydrates and red and processed meats are among the worst foods for inflammation. One potential danger of the keto diet is consuming large amounts of meat, cheese, eggs, butter and bacon. While large, extended-timespan studies on the keto diet and its long-term health impacts are lacking, research has linked red and processed meat to colon cancer and heart disease. Over time, science suggests, the keto diet might do a number on bone health, too.

Because keto is very low-carb, it nixes most plant-based foods like fruits, vegetables, whole grains and legumes, which studies show are linked to reduced inflammation and better health outcomes.

Consuming too few carbohydrates long-term could also potentially shorten your lifespan, according to a September 2018 meta-analysis in the journal Lancet Public Health. Eating less than 40% of calories from carbohydrates was associated with higher risk for death within the next 25 years—particularly when carbs were replaced with animal fat or protein, rather than with plant-based protein or fat. For all of these reasons, we really wouldn't recommend the keto diet.

How to Choose Between the Mediterranean Diet and the Keto Diet

• Clarify your goal. Are you trying to lose weight, decrease your risk of heart disease, improve your blood sugar, keep your brain young, give your gut health a glow-up or something else?
• What does your health care provider recommend? Before trying any diet, consult with your doctor and/or a registered dietitian to determine the best fit based on your goals and current health status.
• How much work are you willing to put in? The keto diet will take more planning to ensure you stay within the recommended carb range and that you get enough fat. Going out to eat and traveling also prove more difficult on a keto diet.
• How long can you keep up with it? While the keto diet leads to rapid weight loss, most people can't keep up keto forever, due to the extreme restrictions. Remember that if you can't continue eating a certain way forever, you won't see the results forever.

The Bottom Line

The majority of research—including a recent study that put these two diets head-to-head—suggests that a Mediterranean diet is not only easier to stick with for a lifetime, but is also healthier for the heart.

If, after reading this recap of the Mediterranean diet versus the keto diet, you're still interested in following a keto diet, EatingWell dietitians recommend seeking out heart-healthy fats most of the time (like fatty fish, nuts, seeds, olive oil and avocados) as part of your low-carb, high-fat menu. For reduced inflammation and better health outcomes, try to limit intake of red and processed meats, butter and cheese.