Figuring out which eating plan to commit to can be confusing. Do you go with the one your friend swore was the secret to her weight loss? The one your favorite celebrity promotes on her social media?
The truth is, there is no one perfect eating plan for everyone. This is why working with a registered dietitian or nutritionist can be helpful; they can provide insight into what types of foods best support your personal health goals. It also helps to look at the science. There are endless studies of specific foods and many popular eating plans, helpful in determining what is and isn’t beneficial for overall health.
Recently, a new study was published in The American Journal of Clinical Nutrition focusing on the Mediterranean diet and the ketogenic diet. The results? Both were shown in being helpful to manage blood sugar and preventing Type 2 diabetes. But before you commit to one of the eating plans, it helps to know exactly how they can be beneficial as well as their pitfalls, if any.
How the Mediterranean Diet and Ketogenic Diet Keep Blood Sugar Levels Steady
For the study, 40 people with pre-type two diabetes followed the Mediterranean diet for 12 weeks. Then, they committed to the ketogenic diet for 12 weeks. The study researchers point out that there are some ways the diets are similar and then there are ways they differ. What they have in common is that both are low-carbohydrate. Non-starchy vegetables, foods low in sugar, and avoiding refined grains are all key components of both diets. Here’s how they are different: The Mediterranean diet includes legumes, fruit, and whole grains while the ketogenic diet minimizes these foods.
Researchers found that both eating plans were linked to stabilizing blood sugar levels, reducing the risk for two diabetes. But they also found that people on the ketogenic diet consumed less fiber than those on the Mediterranean diet.
Related: 110 Foods You Can Eat While Following the Mediterranean diet
Registered dietitian Melissa Rifkin, RD, says that fiber is a key nutrient for keeping blood sugar levels steady. “The Mediterranean diet is rich in fruits, veggies, nuts, seeds, legumes, and whole grains, which all contain fiber. Per serving, most of these foods contain at least two grams of fiber, and some have over four grams in a single serving,” she says.
Registered dietitian Ayat Sleymann, RDN, adds that besides eating a diet rich in the foods mentioned above, following the Mediterranean diet also includes eating fish and seafood two times a week, eating moderate portions (daily or weekly) of eggs, dairy, cheese, and eggs, and rarely eating meat , ultra-processed foods, and sweets.
Rifkin explains that fiber slows down digestion which reduces the speed at which carbohydrate, including sugar, enters the bloodstream. “When the carb slowly enters the bloodstream there is less likely to be a significant jump in blood sugar.” she says. “Also by replacing saturated fats with more heart-healthy fats like olive oil, improves sensitivity to insulin,” Sleymann adds. This is how the Mediterranean diet keeps blood sugar levels steady.
Even though study participants who followed the ketogenic diet consumed less fiber than when they stuck to the Mediterranean diet, Sleymann says the reason why the eating plan was successful in keeping blood sugar levels steady is because it’s low-carb. ,[This] eliminates large spikes in blood sugar that can occur when carbohydrates, mainly simple carbohydrates, are consumed,” she says.
Related: What Is the Ketogenic Diet and How Does It Work?
Steady blood sugar levels are important for several reasons. “Keeping your blood sugar levels in the ideal range can help reduce the risk of developing serious chronic health conditions, like damage to your heart, blood vessels, and kidneys,” Rifkin says.
Sleymann says that balanced blood sugar helps keep our brain functioning optimally, as well as energy and mood levels steady. “When blood sugar levels are disrupted, our blood sugar can lead to increased sugar cravings, fatigue, irritability, poor sleep, brain fog, headaches, anxiety, low energy, weight gain, and diabetes if left unmanaged,” she says. “Blood sugar dictates hunger, cravings, and energy. We feel our best when our blood sugar is balanced; not too high and not too low.”
Related: The Best 6 Free Apps for Managing Diabetes and Blood Sugar
If Both Diet Plans Are Beneficial, Which One Is Best?
Since both the Mediterranean diet and the ketogenic diet had positive effects on blood sugar levels, how do you know which one to follow? Again, this is where working with a registered dietitian can be helpful. It bears repeating that there is no perfect way of eating for everyone. That said, if you are strictly looking at the results of this one specific study, the Mediterranean diet comes out ahead—particularly in terms of heart health.
“While there are almost no carbs in the ketogenic diet, it is quite high in fat and protein. When consumption of animal protein, like red meat, full-fat dairy, and eggs increases, this poses a risk factor for developing heart disease,” says Rifkin. “These foods all contain cholesterol and saturated fat, both of which may increase the likelihood of developing heart disease.”
Both dietitians also point out that the study participants ate less fiber when they followed the ketogenic diet versus the Mediterranean diet—another reason why the Mediterranean diet is better for heart health. “While the Mediterranean diet encourages the consumption of legumes, fruits, and whole grains filled with nutrients and fiber, the ketogenic diet avoids these heart-healthy foods,” Sleymann says. “Eating a high-fiber diet helps to lower total blood cholesterol levels, reduces blood pressure, and inflammation which are benefits missed when following a ketogenic diet.”
Whichever eating plan you decide is best for you, the key—at least according to this study—is to focus on eating foods that are low in sugar and not ultra-processed. If you stick to it, not only will your heart benefit, but your energy and mood will too.
Next up, find out what seven lifestyle changes can help keep your heart healthy.