This year's hottest dieting trends (and which ones really work)

Every year, new diets come and go. After all, they're called fad diets for a reason. At the top of the list for 2019 are the Ketogenic diet (often known as the Keto diet), the Paleo diet and the newest craze – intermittent fasting.

For anyone looking to lose weight this year, here's what you need to know about these trends, and which strategies actually work for long-term weight loss.

The Ketogenic Diet, often known as the "Keto diet" is a very high fat, low carb, low protein diet that puts your body into a state of "ketosis."

Ketosis occurs when your body doesn't have enough carbs to burn for energy, so it instead burns fat. It usually kicks in three or four days after eating less than 50 grams of carbohydrates per day.

Touted by celebrities like Halle Berry, Tim Tebow and the Kardashians, the keto diet has been reported to help improve memory and focus, and to help improve symptoms for a number of diseases and conditions.

"Diets like these may be high in certain macronutrients, but are limiting in others – which can cause imbalance and may also limit a person's vitamin and mineral intake," explained Kayla Steffen, Aramark registered dietitian with Cape Fear Valley Health. "On top of that, a diet like this can be really hard to adhere to for an extended period of time. This can cause yo-yo dieting, which isn't healthy either."

The Paleo Diet, also known as the Caveman Diet, is a higher protein, lower carbohydrate, moderate fat diet that emphasizes eating the way a Paleolithic hunter-gatherer may have eaten more than 10,000 years ago. It encourages the limiting of dairy, sugar, grains and legumes, which are foods that came later as the result of more modern farming practices.

Celebrities who swear by the Paleo diet include Jessica Biel, Matthew McConaughey, Miley Cyrus and Uma Thurman.

"This diet is not well-balanced and it restricts some very good nutrients that come from whole grains and legumes – like your fiber intake," Steffen related. "In addition, research has proven that low-carb diets can cut years off your life."

Explaining this diet is a little more challenging, since there are many methods of intermittent fasting. Generally speaking, this diet allows you to eat what you want, but only during certain windows of time, while fasting during the remaining hours of the day.

The two most common approaches of intermittent fasting are:

Beyonce, Hugh Jackman, Liv Tyler and Christy Turlington have all been reported as using some type of intermittent fasting diets.

"The research is really mixed on intermittent fasting, so I have mixed feelings about it, too," Steffen explained. "For my patients who have a real problem with nighttime snacking, this can be a reasonable strategy. However, I usually encourage patients to try extending the window to 10 to 12 hours per day to allow them more time to cook and prepare healthy foods, while also preventing late-night snacking habits."

Steffen said there are two "fad" diets that have proven to be successful long-term for losing weight.

"The Mediterranean Diet and the DASH Diet are both relatively easy-to-follow and are higher in vitamins, minerals, fruits and vegetables than many of the current hottest trends," she said. "These diets also recognize that we're all human and like to enjoy treats or a drink every now and then, which I think is helpful for a person's ability to stick to it for the long-term."

For those looking to lose weight and stay healthy, consulting with either a registered dietitian or your physician is a great start. Either can provide sound, professional advice based on evidence-based recommendations that have stood the test of time.