(CNN)When the long-awaited 2015 dietary guidelines arrived, they came with three recommended diets, each designed to make sure you get all the nutrients you need, but don't overdo it with calories.
If you enjoy typical American fare but want to make sure you're eating right, the healthy American diet tells you how much of different food groups -- and certain items within each group -- to consume.
If you want to try that Mediterranean diet that has been linked with longevity and healthy brains, the guidelines map it out.
And if you want to shift from meats to grains and vegetables, there are prescriptions for a vegetarian diet.
"There is variety of healthy dietary patterns to follow, whatever tickles your fancy and your palate," said Joan Salge Blake, clinical associate professor in the nutrition program at Boston University and a registered dietitian.
The dietary patterns are important because "(people) need help in knowing what a healthy diet is and to make it as easy as possible, you need to be able to see 'I need this many servings of this group and that group' and understand what the plate should look like," Blake said.
Although the previous installment of the dietary guidelines from the U.S. Department of Agriculture in 2010 also described healthy American, Mediterranean and vegetarian diets, "these guidelines are really focusing on the totality of the diet. ... Super foods are out and super diet is in," Blake said.
However, you shouldn't just pick a diet, fill your plate and leave it at that.
hese diets can be unhealthy if you don't have healthy foods within each group," Blake said.
For example, a serving of broccoli isn't healthy if it's slathered in butter. Blake recommends using the dietary patterns in the guidelines as a starting place and going to the USDA My Plate site (http://www.choosemyplate.gov/) to explore the best ways to satisfy the recommendations for different food groups.
Although all the diets deliver the recommended daily amounts of a slew of nutrients, including protein, fiber, calcium, and vitamins A and C, they fall short in potassium and vitamin E, Blake said. These nutrients, which are important for the heart, muscles and nerves, are notoriously difficult to get, she said. Make sure you eat enough potatoes, tomatoes, bananas and other foods that are rich in potassium. Almonds, sunflower seeds and spinach are good sources of vitamin E.
Talking with a registered dietitian or nutritionist can help you make sure to follow your diet of choice in the healthiest way, said Blake, noting that many insurance plans cover consultation visits.
The healthy American diet
The healthy American diet captures what Americans would eat in a perfect world. As the new guidelines state, it is based on what people in the United States typically consume -- except it includes nutrient-dense forms of these foods and appropriate portion sizes.
"All of The guidelines tailor the number of calories in the healthy American diet (as well as the other two diets) based on age, gender and activity level. For example, a woman in her 30s who does moderate exercise should consume 2,000 calories a day, whereas one who is sedentary should get 1,800 calories.
Based on a 2,000-calorie diet, people following the healthy American eating pattern should consume 2.5 cups of vegetables a day, 2 cups of fruit, 6 ounces of grain, 3 cups of dairy and 5.5 ounces of protein.
For certain food groups, the guidelines prescribe amounts of different food items. In the case of vegetables, they recommend weekly consumption of 5 cups of starchy vegetables such as potatoes and peas, 5.5 cups of red and orange vegetables such as tomatoes and carrots, and 1.5 cups of dark green vegetables. At least half of grains should be whole, such as whole-wheat bread instead of white bread or brown rice instead of white rice. Most dairy products should be reduced fat or fat-free, according to the guidelines. In most cases, the breakdown of food items within a food group is the same for the healthy American, Mediterranean and vegetarian diets, but there are differences between the diets in the amounts of each food group.
The Mediterranean diet
Compared with the healthy American diet, the Mediterranean diet is heavy on protein and fruits and light on dairy. The USDA guidelines recommend people who consume 2,000 calories a day get 6.5 ounces of protein, 2.5 cups of fruit and 2 cups of dairy compared with the 5.5 ounces of protein, 2 cups of fruit and 3 cups of dairy in the healthy American diet. The Mediterranean and American diets both suggest 2.5 cups of vegetables and 6 ounces of grain per day.
The larger serving of fruits in the Mediterranean diet makes it even more important to choose your fruits wisely. Blake recommends consulting My Plate to see what counts as a serving of fruit. Spoiler alert: Whole fruits are best and juices should be 100% fruit.
"We would rather you have more whole fruit so you get more fiber and not just 2.5 cups of juice," Blake said.
Another potential challenge of going Mediterranean is getting enough calcium. The guidelines recommend 2 cups of dairy per day, but that only delivers about 600 milligrams of calcium, and adults between 19 and 50 years old are supposed to get 1,000. Following the American diet gets you closer, about 900 milligrams.
"It's not a fault of the recommendations, that's the just the (Mediterranean) pattern," Blake said. Research has shown that the diet is healthy, but it is important to make sure you get enough calcium as well as vitamin D from other food groups, Blake said. Foods such as spinach, broccoli, tofu and calcium-fortified orange juice all pack in the calcium. Salmon, canned tuna and egg yolks are good sources of vitamin D.
The vegetarian diet
It is no surprise that the vegetarian diet has lower levels of protein than the other two diets. It only recommends 3.5 ounces a day for a 2,000-calorie diet, which still meets the recommended daily amount, compared with 5.5 and 6.5 ounces in the American and Mediterranean diets. In the place of meat and seafood, it prescribes more nuts, seeds, tofu and other soy products -- 7 ounces a week of nuts and seeds and 8 ounces of soy, compared with 4 ounces of nuts and seeds and 0.5 ounces of soy in the other two diets.
There is, however, life for vegetarians beyond nuts and soy. They can also get a lot of protein from items in other food groups, such as beans and peas in the vegetable group, and milk. Blake recommends checking out My Plate for tips on a vegetarian diet. But avoid double dipping. If you count beans as your protein, you should avoid making them your vegetable too. "We want variety within each food group. ... You still want dark green and red and orange vegetables like peppers, sweet potatoes and tomatoes," Blake said.
The vegetarian diet also stands out for featuring more grain -- 6.5 ounces a day compared with 6 ounces in the American and Mediterranean diet.
The same rule stands: Make at least half your grains whole, instead of refined. This recommendation seems to be working, Blake said.
"The public has really heeded that advice, the consumption of whole grains has gone up ... and food companies have reformulated a lot of their products to be whole grain," she said.
The vegetarian diet also recommends 2.5 cups of vegetables and 2 cups of fruit per day.