At times, starting a temporary or fad diet can be a monolithic concept with many questions attached. Where do I start? Which diet is best for me? Why try something new when everything else has failed? Local dietitians weigh in on popular diets on the market today and explain the pros and cons of each.

"I think you can find basically any kind of fad diet you want, which is convenient for a lot of people, but unfortunately those are sometimes just fads or they are simply targeted at weight loss," says Janet Anders, a registered dietitian at Saint Francis Medical Center in Cape Girardeau.

Anders says although people should be considering weight management when they choose diets, they also should consider disease prevention.

"Really look at that whole big picture; what is this going to do for me short term as well as long term," she says.

Raina Childers, a registered dietitian at HealthPoint Fitness in Cape Girardeau, says she thinks there are many diets floating around right now that are sustainable and beneficial for a short period of time, but issues arise when the people on the diets can't make the successful transition of adapting said diet to their normal routine and lifestyle.

"The fear is that they start something dramatic, they can't maintain that, they gain weight back, they get frustrated and we perpetuate sort of that yo-yo dieting thing," she says. "You need a plan to transition to something you can maintain."

When weighing diet options, Childers says people should consider different variables in their life, like their work schedule, any dietary restrictions and their medical history.

"Things come and go, they all have parts of them that are OK; the challenge for most people is that whatever's hot is only hot for a little while, and so we want to help them break that yo-yo diet cycle and try to get help for the long term," Childers says.

Several current popular diets are 21 Day Fix, The Whole30, the DASH Diet, the Mediterranean Diet and others.

21 DAY FIX

Side profile of the legs of a woman standing on a weighing scale

Childers says this diet is based around Shakeology shakes, very structured meal planning with color-coded containers and one 30-minute workout per day.

She says the diet can be beneficial because of its emphasis on whole food consumption and exercise, but its restrictive nature may not be easy to sustain because it isn't cohesive with social dining or dining out.

Anders says research has shown developing habits can take anywhere from 21 to 24 days.

Although it may be possible to form a habit in that amount of time, Anders says dieters should be wary of the idea that one 21-day stint on the diet will "fix you."

"Someone who is kind of a newbie to stuff, too, while you're having such a hard focus on nutrition and then you're doing the fitness with it, I think that can sometimes be complicated," she says.

She says the main thing she likes about 21 Day Fix is that it's one of the only diets that mixes nutrition and exercise in its plan.

"When you start doing these fad diets and they tell you not to exercise while you're doing them, that's like a huge red flag that if you don't have enough energy, it's not going to be something you're doing long term, it's not going to be healthy for your body; you should be able to do physical activity and it needs to be part of a healthy lifestyle when they do that," Anders says.

THE WHOLE30

Childers says The Whole30 promotes consumption of whole foods but also cuts out certain aspects of the diet, like dairy and wheat products.

She says the fruits and vegetables, lean protein and healthy fats are good components of the diet, but it also encourages the cutting of certain dietary aspects that have been proven to have health benefits.

Anders says cutting out food groups can be nerve-wracking and there can be nutrition complications as well. She says to consider how nutritional needs will be met when cutting out entire food groups.

"As registered dietitians, we typically believe in a balanced, moderate eating style, again, something you can maintain," Childers says. "Anything is good for a little while as long as there's a plan on how to transition it to a lifestyle thing that can be maintained."

Anders says when some people take on diets that are restrictive and don't pay attention to other outside factors, like medical history or other issues, the diet could be detrimental to their health. People should consult a physician if they plan to adapt a diet that cuts out certain components of any regular diet.

"We encourage that you look at all food groups and find what works for you in a healthy way," she says. "A lot of times when you are excluding food groups you can cut back on nutrients that are essential, and then if you're not seeing a physician or you're not meeting with a dietitian to help you supplement that part of your diet, you can see complications from that."

OTHER DIETS

Childers says the 5:2 Fasting Diet consists of one fasting day (only consuming 500 calories) per week.

She says the diet may work efficiently when those fasting go through their fasting day and then don't go overboard on the remaining days of the week, but continue to be conscious about what they eat and keep their portion sizes reduced.

Ultimately, Childers recommends consulting a physician before committing to any sort of fasting diet if there are any outside health conditions such as diabetes, pregnancy, blood pressure issues or other problems.

Childers says souping is a new trend replacing juicing, where dieters eat plant-based or broth-based soup for one day a week and then supplement soup for one meal a day during the rest of the week.

Other diets Anders mentions are the DASH, TLC Diet and MIND Diet (ranked No. 1 and tied for No. 2, respectively, on the U.S. News yearly ranking for best diets overall) and the Mediterranean Diet (tied for No. 4). The MIND Diet is a combination of the DASH and Mediterranean diets.

THE BOTTOM LINE

Anders says first and foremost, diets should be considered nutritionally sound and help improve a person's health. Weight loss should be a secondary thought or added benefit.

"I would want to be able to recommend [the diet] to my grandma and my kid," she says.

Anders says people shouldn't consider temporary diets as temporary, and they should try to adapt it to become a lasting healthy lifestyle. Overall, every person is different and requires a diet that suits them best.

"Some people need a lot of structure. You do need to pick something that's going to be the most supportive for what you need, and it's not going to be the same," she says. "No one fits into a singular mold with diets, which is something we've learned over the years."

Anders recommends looking at the U.S. News yearly rankings for best diets overall, because it comes from an expert panel and gives the pros and cons to each diet, making it easier for a person to choose which diet suits them best. The 2016 listing can be found at health.usnews.com/best-diet/best-overall-diets.