(CNN) If you're a fan of the "fat-burning" keto diet, you'll be fired up about its ranking in the 2018 list of best diets from US News and World Report: It's tied for last, along with the relatively unknown Dukan diet .

Both stress eating a ton of protein or fat and minimal carbs, putting the dieter into "ketosis," when the body breaks down both ingested and stored body fat into ketones, which it uses as energy. People on such diets often deal with fatigue and light-headedness as they adjust to a lack of carbohydrates

Though the experts on the US News and World Report panel that created the list said eating that way isn't harmful short-term, they ranked the diets poorly on long-term weight loss success, ease of use and overall impact on health.

For the relatively new keto diet, the experts were especially concerned about extremely high fat content -- about 70% of daily calorie intake -- as well as unusually low carbohydrate levels: only 15 to 20 net carbs a day. The 2015-20 dietary guidelines for Americans suggest that 45% to 65% of daily calories come from carbs but less than 10% from saturated fat.

"When you are on the keto diet, you drastically cut your carbs to only 20 per day. That's less than one apple!" said nutritionist Lisa Drayer, a CNN contributor. "The keto diet is just not sustainable over the long term. It doesn't teach you how to acquire healthy eating habits. It's good for a quick fix, but most people I know can hardly give up pasta and bread, let alone beans and fruit."

The expert panel was particularly concerned for people with liver or kidney conditions, "who should avoid it altogether," the report said, adding that there was not enough evidence to know whether the diet would help those with heart issues or diabetes. Because of the recommended "cycling" nature of the diet, taking breaks and then starting it again, experts also warn that hormones could fluctuate.

Another popular low-carb diet, Whole30, was also at the bottom of the list, just before keto and Dukan. Whole30 is a 30-day diet designed to end "unhealthy cravings and habits, restore a healthy metabolism, heal your digestive tract and balance your immune system," according to its website.

The panel slammed the diet as having "No independent research. Nonsensical claims. Extreme. Restrictive." and tied it with the raw food diet as "the worst of the worst for healthy eating."

First place is a tie

For the first time, the well-researched Mediterranean diet moved into first place, tied with the DASH diet. DASH, which stands for Dietary Approaches to Stop Hypertension, has held the top spot for eight consecutive years. Both diets also tied for healthiest in the rankings.

"What I love about both the DASH and Mediterranean diets is that they offer guiding principles for eating, like eating more fruits and vegetables, as well as whole grains, fish, legumes, nuts and low-fat dairy foods," Drayer said. "I personally love the fact that a daily glass of red wine is encouraged as part of the Mediterranean diet."

The DASH diet is often recommended to lower blood pressure. Its premise is simple: Eat more veggies, fruits and low-fat dairy foods while cutting way back on any food high in saturated fat and limit your intake of salt.

The meal plan includes three whole-grain products each day, four to six servings of vegetables, four to six servings of fruit, two to four servings of dairy products and several servings each of lean meats and nuts/seeds/legumes.

Studies have shown that following this diet can reduce blood pressure in a matter of weeks.

The Mediterranean diet also ranked first on the US News and World Report list for easiest diet to follow, best plant-based diet and best diet for diabetes. It came in second for best heart-healthy diet, just behind DASH.

The diet emphasizes simple, plant-based cooking, with the majority of each meal focused on fruits and vegetables, whole grains, beans and seeds, with a few nuts and a heavy emphasis on extra virgin olive oil. Say goodbye to refined sugar or flour. Fats other than olive oil, such as butter, are consumed rarely, if at all.

Meat can make a rare appearance, but usually only to flavor a dish. Meals may include eggs, dairy and poultry, but in much smaller portions than in the traditional Western diet. However, fish are a staple, and an optional glass of wine with dinner is on the menu.

Photos: Delicious Mediterranean diet foods The Mediterranean diet is easy to find in the grocery store, contains nutrients that are known to enhance longevity and has other health benefits that are backed by peer-reviewed, scientific studies. Broccoli makes the list because it's one of nature's most nutrient-dense foods, with only 30 calories per cup. That means you get a ton of hunger-curbing fiber and polyphenols -- antioxidants that detoxify cell-damaging chemicals in your body -- with each serving. Hide Caption 1 of 12 Photos: Delicious Mediterranean diet foods Doctors suggest using olive oil rather than butter to make your meals. A Spanish study found a Mediterranean diet supplemented with extra-virgin olive oil reduced the incidence of major cardiovascular events among patients with a history of heart disease. Hide Caption 2 of 12 Photos: Delicious Mediterranean diet foods Quinoa is the popular whole-grain du jour because it also contains a good dose of protein to help build muscle. Yet including any type of whole grain in your diet -- from barley to brown rice -- will aid in weight loss by filling you up for fewer calories. Hide Caption 3 of 12 Photos: Delicious Mediterranean diet foods Blueberries are often singled out as a kind of superfood because studies have shown they aid in everything from fighting cancer to lowering cholesterol. But all berries, including raspberries, strawberries and blackberries, contain antioxidants and phytonutrients . Worried about the price of fresh fruit? Experts say the frozen kind is just fine. Hide Caption 4 of 12 Photos: Delicious Mediterranean diet foods Many dieters shy away from nuts because of their high calorie and fat count. But studies show that eating a handful several times a week can prevent heart disease and ultimately help you shed pounds since they fill you up and stop you from snacking on other things. Almonds, in particular, contain lots of monounsaturated fats and fiber. (Healthy swap: Replace peanut butter with almond butter.) Hide Caption 5 of 12 Photos: Delicious Mediterranean diet foods Salmon is also a good source of lean protein. With this diet, doctors suggest eating fish at least two times a week. Salmon provides a high dose of omega-3 fatty acids, which studies show significantly lower the risk of heart disease. Omega-3 fatty acids fight back by reducing inflammation and slowing the rate of plaque buildup in blood vessels. Hide Caption 6 of 12 Photos: Delicious Mediterranean diet foods Beans, beans, the magical fruit; the more you eat, the more ... you lose weight. Black, kidney, white and garbanzo beans (also known as chickpeas) are good for fiber and protein. They fill you up and provide muscle-building material without any of the fat that meat can add to your meal. Hide Caption 7 of 12 Photos: Delicious Mediterranean diet foods Eating a breakfast high in protein is a good way to keep hunger at bay throughout the day. Eggs are full of choline, a nutrient that helps block fat from being absorbed in the liver. Choline may also help in preventing memory loss. Hide Caption 8 of 12 Photos: Delicious Mediterranean diet foods Spinach is a great source of iron, which is a key component in red blood cells that fuel our muscles with oxygen for energy. But researchers in Sweden identified another way in which these greens might keep you charged: Compounds found in spinach actually increase the efficiency of our mitochondria , the energy-producing factories inside our cells. That means eating a cup of cooked spinach a day may give you more lasting power on the elliptical machine (or in your daily sprint to catch the bus). Hide Caption 9 of 12 Photos: Delicious Mediterranean diet foods Walnuts are packed with tryptophan, an amino acid your body needs to create the feel-great chemical serotonin. (In fact, Spanish researchers found that walnut eaters have higher levels of this natural mood-regulator.) Another perk: "They're digested slowly," said Dr. David Katz, director of the Yale Prevention Research Center. "This contributes to mood stability and can help you tolerate stress." Hide Caption 10 of 12 Photos: Delicious Mediterranean diet foods Asparagus is one of the best veggie sources of folate, a B vitamin that could help keep you out of a mental slump. "Folate is important for the synthesis of the neurotransmitters dopamine, serotonin and norepinephrine," said David Mischoulon, associate professor of psychiatry at Harvard Medical School. All of these are crucial for mood. Hide Caption 11 of 12 Photos: Delicious Mediterranean diet foods It's not a requirement to drink it on this diet, but if you do drink alcohol, red wine in moderate amounts can be good for your health. Moderation means one drink for women and two for men, by the way. Studies show red wine can help protect against heart disease. Hide Caption 12 of 12

The flexitarian diet came in third on the list of best overall diets for its emphasis on whole grains, fruits, veggies and plant-based proteins. It's basically a vegetarian diet that allows the occasional piece of meat or fish, thus making it "flexible."

The ever-popular Weight Watchers diet was ranked fourth, followed by the MIND diet, a combination of the Mediterranean and DASH diets that some may find a bit easier to follow, as it requires less fish and fruit.

Both the MIND diet and the Mediterranean diet have been shown in studies to lower the risk of Alzheimer's disease.

Best weight-loss diets

Weight Watchers topped the list of best weight-loss and best commercial diet plans, and it tied with HMR for best fast weight-loss diet. HMR, the Health Management Resources program, involves purchasing meal replacements, such as shakes, nutrition bars and multigrain cereals, and adding vegetables and fruits to round out the meals.

Since 2015, Weight Watchers has been focused on its Beyond the Scale program. It is designed to help people move more and focus on overall well-being, including more "me" time, which includes mindfulness and self-compassion.

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The US News and World Report expert panel -- made up of 25 experts from major medical centers across the country -- gave Weight Watchers top points for being healthy, also stressing the importance of support for dieters.

Pointing to a 2006 British Medical Journal study , the panel said that "programs like Weight Watchers that offer emotional support and group meetings lead to higher compliance than a do-it-yourself dieting."

Drayer agreed: "I've always been a fan of Weight Watchers because it teaches you how to incorporate all types of foods into your diet, and it also offers a support component, which can be extremely beneficial."

But whatever diet you choose, she recommends choosing the one that fits your lifestyle and that you can stick to over the long term.

"I always recommend meeting with a registered dietitian, who can take into account your health history, lifestyle habits, likes and dislikes, and develop an eating plan that is specific to your needs," she added. "I also recommend checking with your doctor first before starting any new diet plan."