Is the Keto Diet Safe? What You Need to Know Before Starting

The widely popularized keto diet has been successful in helping people lose weight, but it's not everyone.
Updated 23 December 2021
Is the Keto Diet Safe? What You Need to Know Before Starting

The keto diet is safe.


The keto diet is safe for some, even beneficial. However, it may be extremely harmful to those with certain health risks and conditions. In addition, the keto diet is dangerous when followed long term.

As a weight loss diet, keto can be effective. However, it is not a long-term solution as it can lead to nutritional deficiencies, kidney problems, liver failure, and other health conditions.

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Sections on this page
  1. How the Keto Diet Works
  2. Effects of the Keto Diet
  3. Keto Diet for Weight Loss
  4. Is the Keto Diet Safe?
  5. Who Should Not Follow a Keto Diet?

The ketogenic (keto) diet has been around for a while, gaining popularity within the last five or so years. Although the diet was created to help treat children with epilepsy, adults now follow the diet to lose weight quickly. But is the keto diet safe?

How the Keto Diet Works

Similar to other low-carb diets, such as the Atkins diet, the keto diet limits your daily carbohydrate intake drastically. You replace your carbohydrates with fat, with the primary goal of putting your body into a state of ketosis, which has been found to help with weight loss. Basically, starving your body of carbohydrates means you’ll be burning fat for energy. 

Technically, a keto diet should consist of:

  • Maximum of 20-50 grams of carbohydrates per day (mainly from non-starchy vegetables)
  • Around 1 gram of protein per 1 kilogram (~2.2 pounds) of your body weight
  • 75%+ of total calories from fat

Many people do the keto diet for 28 days only to lose weight quickly. However, several different versions of the keto diet have different “rules.”

Effects of the Keto Diet

Many people decide to follow the keto diet as a quick way to lose weight. However, there are other health benefits, including:

  • Reducing the risk of heart disease
  • Treating children with epilepsy (helping to reduce seizures)
  • Slowing tumor growth (used as an additional treatment for cancer)
  • Reducing symptoms of and slowing the progression of Alzheimer’s disease
  • Treating brain injuries
  • Helping reduce insulin levels

However, as with many diets, there are some adverse effects of following the diet, especially long term. These include:

  • Kidney stones
  • Additional fat in the liver, which can cause liver inflammation and failure
  • Low levels of protein in the blood, which can cause mild to severe symptoms
  • Nutrient deficiencies

Keto Diet for Weight Loss

Studies suggest the keto diet is a better option for weight loss than a low-fat diet, with one study showing those on a keto diet lose more than twice as much weight than those on a low fat/calorie diet. 

According to a U.S. News & World Report survey in conjunction with America’s Test Kitchen, 80% of respondents would recommend the keto diet, with 94% experiencing positive health changes. 

Is the Keto Diet Safe?

The keto diet can be safe for some, even beneficial. However, it’s not recommended for long-term use or a complete lifestyle change. The keto diet may be safe for 3-6 months maximum, but any longer than that, it can cause serious health issues, including malnutrition and liver failure. 

The Keto Diet Is Not a Long-Term Weight Loss Solution

Since the keto diet is not considered safe for long-term use, many question its effectiveness for healthy weight loss. While you may lose weight initially, since the diet (like all fad diets) is not a lifestyle change, you may find you put the weight back on once you’re no longer on keto.

Before starting any diet, you must talk to your doctor first. Although the keto diet is considered safe for some, it may not be safe for you. For example, you may have underlying conditions that make the keto diet dangerous, or you may be on medications that do not interact well with a keto diet. 

Is Keto Safe as a Long-Term Diet Plan?

Dietitians recommend those on the keto diet only do it short-term, as a long-term change can lead to serious health risks and nutrient deficiencies. The most common length for a keto diet is 28 days, which is generally considered safe. However, if you want to stay on the keto diet for longer, it’s recommended that you only do it for 3-6 months maximum. 

Always speak to your doctor before starting a keto diet, no matter the length. Each person is different—what is recommended for one person may not be the best option.

One study found that long-term keto dieting (specifically two years on the diet) did not cause any significant negative side effects in obese people. However, it did help them lose weight and improve their cholesterol levels. 

Is the keto diet safe long term? No.

Is Keto Safe for Pregnancy?

There are mixed opinions on whether or not the keto diet is safe for pregnant women. However, most dieticians and doctors do not recommend it. The reason why it’s generally not recommended for pregnant women is because it restricts the amount of carbs you can eat, including certain fruits and vegetables that provide the necessary vitamins and minerals that a growing fetus needs. 

Specifically, you could be depriving your unborn baby of the following vital nutrients:

  • Vitamin D
  • Vitamin B-12
  • Vitamin E
  • Folic acid

These vitamins are responsible for things like spinal cord and nerve development and healthy teeth, bones, and muscles. Folic acid can also help prevent spina bifida in babies. 

Is the keto diet safe during pregnancy? No.

Is the Keto Diet Safe for Diabetics?

While the keto diet has been found to help reduce blood sugar levels in those with type 2 diabetes, it’s important to remember that you should only follow the keto diet short term. It’s usually ok to follow the diet to trim down and reduce the need for insulin, but it’s not a miracle cure or long-term solution for diabetes. 

As for type 1 diabetes, the keto diet may lead to unsafe weight loss, as not everyone with this type of diabetes needs to lose weight. 

Additionally, being on the keto diet when you have diabetes puts you at risk of diabetic ketoacidosis, when your insulin levels are so low that your blood glucose levels end up being too high. This is especially risky for those with type 1 diabetes. Diabetic ketoacidosis is a medical emergency that can result in a coma. 

Is keto safe for people with diabetes? Your doctor can let you know if it’s safe for you.

Is One Shot Keto Safe?

One Shot Keto is a weight loss supplement that works like the diet (putting your body into ketosis) but eliminates the need for actual dieting. Taken in pill form, One Shot Keto puts your body into ketosis, but instead of doing this through eliminating carbs, the pill uses beta-hydroxybutyrate (BHB). 

One Shot Keto

BHB puts your body into ketosis without the hassle of dieting, helping you rid your body of extra glucose so you can start burning fat faster. Other ingredients in One Shot Keto help:

  • Your body stay in ketosis
  • Accelerate weight loss
  • Support your metabolism
  • Support your energy levels

It has been claimed that One Shot Keto helps with long-term weight loss, compared to other fad diets (including the keto diet), which are just a short-term solution. 

However, there is little research or information out there on the health risks of taking One Shot Keto. Before taking this diet supplement, talk to your doctor and confirm that it’s safe for you. Products like these can be extremely harmful to certain people. 

Who Should Not Follow a Keto Diet?

  • Those with kidney damage
  • Those who are at risk of heart disease
  • Those with heart conditions
  • Those with pre-existing liver or pancreatic conditions
  • Those with type 1 diabetes
  • Those who have had their gallbladder removed
  • Those with a history of eating disorders
  • Underweight people
  • Children under 18 years old (unless prescribed by a doctor)

Of course, everyone is different. How the keto diet affects you can be drastically different from how it affects someone else. Do not start the keto diet before talking to your doctor and/or dietitian.