All the reasons you should and shouldn’t try the keto diet, according to experts

Does it feel like the whole world has gone keto? Yeah, we hear you. From social media posts to news coverage to celeb testimonials, the keto diet is the trendiest trend of 2019. There are plenty of reasons to try keto, but there are just as many (or more) reasons to skip it. If you’re lost in a sea of carbohydrate confusion and don’t know what would be best for you, we spoke with experts about all the reasons you should and shouldn’t do keto.

The basic principles of the keto diet are simple enough—eat more fat (like meat and nuts) and very few carbohydrates. But the science behind it is actually pretty complex. Eating this way leads your body to go into a state of ketosis, which makes you burn fat instead of carbohydrates. This is one of the reasons the diet is often praised as a weight-loss solution.

However, losing weight isn’t the only reason people try keto. At the same time, just because you may want to lose some pounds, that doesn’t mean keto is necessarily the right fit for you.

As you’ll see below, there are varying opinions on the benefits and downsides to keto. And this article is absolutely no substitute for medical advice. Readers should always consult a doctor before drastically altering their eating habits. But if you’re curious about why some specialists suggest or don’t suggest keto, here are some of the main reasons.

Reasons you may want to try keto

You have epilepsy

“The ketogenic diet has been successfully used in the treatment of patients with epilepsy, both children and adults, for nearly a century,” said Dr. Tanya J. W. McDonald of Johns Hopkins University School of Medicine. In fact, the diet started as a “medical therapy” to treat epilepsy. Dr. McDonald said physicians think it has an impact on seizures because it impacts things like metabolic regulation, neurotransmission, oxidative stress, inflammation, and genomic expression.

You have a progressive neurological disorder

Dr. Terry Wahls noted that, in some cases, a low-carb diet such as keto can ease symptoms of progressive neurological disorders, including multiple sclerosis (MS) and Parkinson’s, by helping with fatigue, cognitive decline, and loss of brain volume. She noted that one small pilot study showed that the keto diet improved the quality of life for patients with relapsing-remitting MS.

You like the food that’s part of the keto diet

“If eating foods high in fat and very low in carb—like avocado, ribeye steak, and olive oil—sounds good to you, then keto may be a great fit,” said Pam Nisevich Bede, registered dietitian and keto expert with nutrition product manufacturer Abbott. Because, as she noted, one of the most important aspects of trying a diet is whether or not it’s something you will actually stick to long-term. So review the allowed foods and see if it’s something you’d be into.

You have polycystic ovary syndrome (PCOS)

Licensed nutritionist and director of education for Designs for Health Jason Bosley-Smith told HG about a small pilot study at the Cleveland Clinic that used keto to help women with irregular periods and PCOS. A group of women, who all had irregular periods before starting the diet, tried keto for six months. Besides losing weight, “each participant resumed regular menstruation and reduced PCOS symptoms” within a month to two months. 

You have a history of obesity

One of the biggest reported benefits of the keto diet is weight loss, since your body is burning fat instead of carbs. Internal medicine physician Dr. Kyle Varner said, “The standard American diet over the past decades has seen an astronomical increase in refined carbohydrates and sugars being consumed,” and that can lead to increased body fat. The keto diet mimics how we believe our ancient ancestors ate—high fat, low carb—and has proven to help with weight loss, sometimes very dramatically.

You have type II diabetes

Halle Berry has claimed that the keto diet has helped her diabetes, and there is some science to back this up. The CEO of Perfect Keto, Dr. Anthony Gustin, said that type II diabetes is usually characterized by insulin resistance, “which means the body no longer effectively utilizes carbohydrates.” He said, “A ketogenic diet is a great way to provide an alternative energy source to replace carbohydrates and lower common markers of diabetes.”

You have a history of Alzheimer’s disease in your family

Scientists are still trying to figure out the causes of Alzheimer’s, but multiple specialists we spoke to said there is some research to show that a ketogenic diet may help with Alzheimer’s. Dr. Jacob Wilson said that recent research indicates that Alzheimer’s is “associated with a decrease in blood glucose uptake in the brain” and that “this has important implications for Alzheimer’s disease because landmark studies have confirmed that, unlike glucose, ketone uptake and utilization in the brain are not impaired in individuals with Alzheimer’s.” Because of this, he said, “It is plausible that a ketogenic diet may stave off and slow the progression of Alzheimer’s.” But this is still very far from a sure thing.

Reasons you may NOT want to try keto

You have issues with your blood pressure

Dietitian and spokesperson for the Academy of Nutrition and Dietetics Ginger Hultin said, “When you drastically alter your diet, blood pressure can be affected and there’s a risk of going too low or too high.” So if you’re on medication to regulate your blood pressure, you might want to think twice before trying keto (or any extreme diet).

You’re a woman

Sorry, y’all. But certified holistic nutrition consultant Rachel Fiske, who serves on the advisory board for Smart Healthy Living, said you should think twice about this diet if you’re a woman. “Many women end up experiencing female hormone imbalances and other hormonal problems” when doing the keto diet long-term, Fiske said. “So while a keto diet might be an effective way to kick-start weight loss, curb sugar cravings, and teach your body how to burn fat for fuel, it might not be best for women in the long run.”

You don’t often have control over what or when you’re eating

Still live at home and your parents do the cooking? Travel a lot? Don’t have access to a full kitchen? Hultin pointed out that “being on a true ketogenic diet requires planning, tracking, and calculations.” So if you don’t have the time or space to do it right, you probably shouldn’t do it at all.

You have a history with eating disorders or other mental health conditions

Licensed mental health counselor Molly Bahr said that because keto is an extremely restrictive diet, it can lead to disordered eating. She said, “Keto comes with too many risks, including increased anxiety, food fears, body dissatisfaction, isolation, insomnia, and depressed mood.” Bahr said it is much better for your mental health to practice intuitive eating, especially since people with a history of eating disorders, disordered eating, or anxiety could quickly relapse when doing keto. “If the way you are eating is causing anxiety around certain foods or groups of foods like carbohydrates, experiencing guilt when the food is eaten or when eating past comfortable fullness, or you’re spending a significant amount of time thinking about food, weight, and your body, these are clues that a diet may not be helpful and causing more harm than good,” she added.

You often get constipated

Talking about bowel movements is never the most fun conversation to have. But you know what’s less fun? Not being able to go at all. Hultin said a side effect of keto can be severe constipation. So if you already struggle with BMs, keto could make it worse.

You’re pregnant, trying to get pregnant, or breastfeeding

Fiske said pregnant women and women who are breastfeeding shouldn’t eat a low-carb diet since “their nutritional needs are far greater during these stages of life.” Same goes for children. And Dr. Wahls noted that the keto diet can suppress sex hormones, so there’s that to consider, too. Bosley-Smith said that pregnant women should “consult with their physicians and adopt a well-rounded, nutritionally dense diet that supports their health and specific needs during pre- and peri-natal times.”

You don’t like to exercise 

Dietitian Meg O’Rourke is no supporter of “diets.” But she did say that people who are willing to do some serious exercise—as in an hour or more five to six times a week—could benefit from keto. Otherwise, she thinks keto is a “bad idea.”

“The result would be that you would lose all the weight, only to gain it all back again,” O’Rourke said about not exercising on keto. “Dieting alone will create fat loss, but also muscle loss. When you are done with the diet, you will have less muscle and a slower metabolism than when you started.” And because more muscle means a faster metabolism, you’d have to do weight bearing and weight resistance exercises to build up your muscle mass.

You don’t have a doctor

Pretty much every expert we spoke to mentioned the importance of working with a doctor while on keto—and that’s not just for people who have serious health diagnoses. “If you start keto, you need to be working with a doctor and dietitian,” Hultin said. “You should get baseline labs drawn and then monitor them closely as you continue on the diet.” Bottom line: No doctor, no keto.

Besides temporarily annoying symptoms like keto breath, there are significant reasons you should think twice about doing keto. But whatever you decide to do with your diet, make sure you do it with the support of an expert.