There are a lot of interesting diet trends right now that celebrities swear by to lose weight and feel better. However, are these eating habits — like keto, intermittent fasting, juicing and more — actually healthy for you? Life & Style exclusively spoke with three registered dietitians — Sharon Palmer, MSFS, RDN, Sammi Haber Brondo, MS, RD and Dr. Rachel Paul, PhD, RD — about some of the hottest diet trends of the moment and got their (degree-backed) opinions on how beneficial they can be to your overall wellness.

Ketogenic Diet

The very popular keto diet is a low-carb and high-fat diet eating plan that everyone from Kourtney Kardashian to Halle Berry has touted the benefits of. Basically, the majority of your carbohydrates being replaced with fat kicks your body into the metabolic state of ketosis. Your body is then forced to burn fat for energy. While that sounds ideal, it’s probably not a great longterm plan.

Kourtney Kardashian Takes Sexy Bikini Selfie
Courtesy of Kourtney Kardashian/Instagram

SP: “It is definitely not healthful for the longterm. It eliminates many essential, healthful foods from your diet — such as many fruits, vegetables, whole grains … and foods that are linked with optimal health and longevity,” Palmer, who’s known as The Plant-Powered Dietitian, explained. “Not to mention the quality of life associated with this diet, you can’t eat out or socialize around foods very easily … It can promote poor eating behaviors and psychology around the enjoyment of foods and meals.”

SHB: “The keto diet is not a longterm diet or a sustainable lifestyle. Our brain alone needs 130 grams of carbs per day to function,” Brondo noted about keto, which generally advises about 20 to 50 grams of carbs per day, depending on the individual. “Our brain can manage if it has to, but still, our red blood cells need those 130 grams of carbs per day for them to function. The keto diet isn’t safe and also is not sustainable. Following such a low-carb diet for a long period of time leaves no room to also enjoy life.”

RP: “The main benefit I see from the keto diet is that the person is full (i.e. not hungry) compared to other diet approaches,” Dr. Paul said. “However, there aren’t enough long term studies to determine whether Keto is safe for the longterm. Nutrition is the newest science, we’re still discovering new vitamins and nutrients, and it’s safest to eat a variety of foods rather than cut out certain food groups completely.”

Dr. Paul broke down a few health concerns that she sees in some people such as “raised cholesterol” from “super low-carb diets.” She added, “In addition, without (hardly) any carbohydrates, the person will miss out on some key vitamins and minerals and may negatively alter their gut microbiota … Any diet for a short period of time is likely fine (of course talk to your doctor first before starting anything new), but for the long term, I wouldn’t recommend something so strict.”

Summary: Keto as a short-term dieting option is most likely not harmful, but it is not something that should be maintained for long periods of time. Carbs are not the enemy, they are part of a well-balanced diet.

Intermittent Fasting

Intermittent fasting is very popular among fitness trainers right now. It’s a pattern where you cycle through periods of eating and fasting. For example, your eight-hour window for eating throughout the day might be from 10 a.m. to 6 p.m. and then the next 16-hours is spent fasting (a.k.a. not consuming foods). This is a favorite among Vanessa Hudgens, who credits the eating style for making her feel her physical best.

SP: Palmer explained that “research hasn’t consistently supported” the idea that intermittent fasting gives your metabolism a boost. It has been “shown to cause weight loss” — but not for the reason you might think. “It makes sense that you would lose weight because you reduce the number of meals and calories you consume,” she said.

The biggest issue Palmer sees with intermittent fasting is that it could affect your relationship with food. “There are some concerns that it might create unhealthful eating behaviors, with binging on the non-fast days and hunger and deprivation on the fasting days, as well as lower intake of key nutrients. It is not the healthiest way to lose weight. But it seems to work for some people and there is a history of fasting patterns in traditional diets,” she added.

SHB: Not fasting properly may even have a negative effect on your metabolism, according to Brondo. “Intermittent fasting actually has the opposite effect on your metabolism, as going too long without eating can slow the metabolism,” she said. “It’s not an effective weight-loss tool or a sustainable diet. Being overly hungry makes it easier to overeat at your next meal.” The dietitian added, “Even if you get used to the hunger, it means often declining social events and living life based on your intermittent fasting schedule. It’s not a healthy (or particularly fun) way to live.”

RP: On the other hand, Dr. Paul noted that it could help add discipline to a person’s daily food routine. “I find the benefits of intermittent fasting more psychological than anything. If having set hours of eating helps you not eat breakfast if you’re not already a breakfast person, and not eat ice cream late at night (because we’re not eating broccoli at midnight, usually!), then intermittent fasting may be for you.” She explained, “What’s more important is what realistically works for the individual person. If you always get hungry for breakfast, for example, please eat breakfast!”

Summary: Know your body and don’t starve yourself. Intermittent fasting may or may not make you lose weight but be cautious if you’re the type of person who psychologically doesn’t respond well to strictly regimenting your meals.

Juicing

Jenna Dewan Drinking Celery Juice
Courtesy of Jenna Dewan Instagram

People often turn to “juicing” when they want to “detox” their body. It usually refers to doing a juice cleanse, where you primarily consume fruit and vegetable juices while avoiding solid foods. The period of time recommended can be anywhere from one to ten days. All three of the experts confirmed that your body naturally detoxes itself so there’s no scientific backing that says you need to do more. “Your liver is a natural detox. You don’t need anything else!” Dr. Paul said.

SP: Keeping your diet filled with healthful food and staying hydrated will do the trick, Palmer said. “There are some diet strategies that support your body’s natural detox system — including plenty of water, fruits and vegetable consumption, dietary fiber, cruciferous veggies, healthful protein sources and adequate micronutrient intake.”

SHB: But, juicing makes you feel great? Brondo explained that sensation by adding, “If you’re doing a juice cleanse and only drinking juice, you might feel the illusion a ‘detox’ because there’s literally no other food going into your body. There’s nothing inherent about a juice that detoxes the body. Juices have beneficial vitamins, minerals and fiber, but don’t have magic powers.”

Summary: Juicing is an easy way to add more fruits and veggies to your daily diet, but it will not “detox” your body more than it already naturally does.

Adaptogen Diet

“This is the idea that you can use herbs to restore balance among stress in lifestyle. Certain herbs are thought to help with this purpose by mediating the adaptive stress response in the body.,” Palmer explained while adding, “There are about 70 herbal plants that have documented adaptogenic properties.” However, she noted that this topic is still fairly unresearched. “More studies are needed to understand how they work and if they really do indeed help,” she said. It’s now easy to find some of these popular items like ashwagandha, reishi mushroom and maca in capsule form at your local grocery store, but Palmer and Brondo both recommend adding the ingredient to your daily diet.

SP: “It’s always a good idea to include whole foods in your diet for benefits, as you can’t take in too much via the diet — when you take supplements you can be consuming large amounts of compounds,” Palmer explained. “However, some herbs and botanicals have been found to have benefits at higher levels in research, without toxicity concerns. It’s important to look for documented benefits and safety levels in research before trying a herb/botanical regimen. Check with your health care provider before you start a new supplement regimen.”

SHB: “Most research has only been done on animals, not humans. If you’re interested in trying them though, there’s no harm to them,” Brondo said. “While they’re not 100 [percent] proven to work, they also can’t hurt. I recommend adding them to food.”

Summary: Adaptogens may not be magical, but they most likely won’t hurt. If you’re going to start consuming new ingredients via pill, check with your healthcare provider.

“Impossible” Meats

The Impossible Burger — a plant-based meat substitute that is astoundingly similar to real red meat — is sweeping the nation. Jay-Z, Katy Perry and Serena Williams are just a few of the high-profile investors in the company. The concoction has 21 ingredients, which Brondo noted are “Soy protein, coconut oil, sunflower oil and ‘natural flavors.’ The other ingredients in it are in trace amounts.” Palmer added that it is “a highly processed food, but the ingredients are generally safe.” Should you give up beef for this new product altogether? Adding more meat-free days to your diet are beneficial but Impossible Meats may not be your holy grail.

Katy Perry Burger Costume by Moschino
ANDREW MORALES/WWD/Shutterstock

SP: “The concern I have is the high amount of saturated fat, which has been linked with heart health concerns,” Palmer said. “There are certainly more healthful plant foods you can include in your diet, such as lentils, beans, quinoa and tofu. Simple, minimally processed plant foods are better for overall health. But I don’t think there is anything wrong with including an [Impossible Burger] in the diet once or twice a week and it can help people move to a more plant-based diet, which has health benefits. Plus these products have a significantly lower eco-footprint than animal foods.”

As far as opting for a more plant-focused diet overall, Palmer added, “There are benefits for eating primarily plant-based diets over animal-rich diets, based on research. These are heart health, reduced cancer risk and lower risk of obesity.”

SHB: “People often wonder about the soy leghemoglobin, or heme, in the Impossible Burger. This heme is genetically engineered (a.k.a. GMO) to make the burger taste and ‘bleed’ like beef,” Brondo explained. “It’s Generally Recognized as Safe — or GRAS — by the FDA. Although there are definitely more whole food ways to get protein … there’s nothing to be worried about in the ingredient list.”

RP: Dr. Paul recognized that “there are huge environmental benefits of lowering meat consumption,” but her vote is to go with what you know. “I personally trust the animal more than I trust the scientist in the lab. The fewer ingredients, and especially all ingredients that you, your mom and your grandmother could identify, the better,” she said. “Try using nuts, seeds, cheese, yogurt, tofu, edamame in place of meat once in a while.”

Summary: The Impossible Burger isn’t necessarily the answer to all your plant-based prayers, but trying “Meatless Monday” or incorporating more vegan and vegetarian meals into your weekly diet is beneficial for your health and the environment.

When it comes to dieting, there is no such thing as a quick fix. Be smart, treat your body well and if a fad sounds too good to be true … it probably is.