Dec. 17, 2019—The ketogenic diet may sound like the latest thing, but it's been around for a long time. In the 1920s, this diet was found to help control epilepsy. Today, however, most people with epilepsy opt for medication—in part because the keto diet is so hard to follow.
It's high in fat and very low in carbohydrates. That includes carbs that come from fruits and vegetables, the usual mainstay of most recommended diets.
Besides epilepsy, it's often used to help manage diabetes and is increasingly used for weight loss. But is it safe?
How the keto diet works
According to the American Diabetes Association (ADA), the hallmark of the keto diet is its unusually high fat content. Fat makes up 65% to 80% of its daily calories, in fact. Protein makes up 15% to 25% of calories. And carbs are limited to just 5% to 15% of calories.
That's achieved by eating foods like eggs, meats, fish, avocados, nuts, butters, cheese, seeds, oils, berries and some low-carb green vegetables. The diet cuts out most other fruits and vegetables, grains, beans, milk, sweets and alcohol.
Typically the body runs on glucose (blood sugar) for energy. However, fewer carbs mean less glucose as fuel. Instead, the body converts fat to substances called ketones—and uses them for energy. This results in a state known as ketosis, which burns fat. To the body, it's essentially a partial fast, says the Academy of Nutrition and Dietetics.
According to the ADA, research suggests there are short-term benefits of the keto diet for people with type 2 diabetes. (Studies on type 1 diabetes are more limited.) It can lower A1C dramatically. People who practice the keto diet are often able to reduce their insulin intake significantly.
But not a lot is known about the long-term risks. And in the short term, the diet raises the risk for excessively low blood sugar, or hypoglycemia. That makes it critical for people with diabetes to check their blood sugar regularly, especially when they first start the keto diet.
Worth the risk?
Even if you don't have epilepsy or diabetes and are considering the keto diet for other reasons, such as weight loss, there are drawbacks to be aware of:
Missing nutrients. Without milk, for example, it can be hard to get your daily calcium and vitamin D. Take away whole grains, fruits, beans and potatoes, and it's tough to get enough fiber to stay regular. Unless you're eating lots of low-carb leafy green vegetables, you'll miss out on vitamins A, C, K and folate too.
Cost. You'll be trading inexpensive grains and produce for pricier beef, fish, poultry and cheese. Plus, chronic constipation may require you to buy fiber supplements.
Health complications. Most health experts agree that the keto diet isn't recommended for anyone with chronic kidney disease. And there are concerns about the long-term effects of a high-fat diet on heart health. It's also not right for people with pancreatic disease, liver conditions, thyroid problems, gallbladder disease or a history of eating disorders.
Dehydration. Carbs help the body hold on to water. By eating fewer of them, you may be more prone to dehydration.
Difficulty. The keto diet is very restrictive. According to the ADA, many health experts question how long a person can realistically give up carbs. So it may be impractical to maintain. And people who lose weight on the keto diet may gain it back when they stop.
If you're considering trying the keto diet, talk about the pros and cons with your doctor first. Your doctor may also be able to refer you to a dietitian, who can help you find an eating plan that's right for you.
You can learn more about how the keto diet is used by people with epilepsy in this quick quiz.