How long is it safe to be in ketosis?

This is a question that may come up when people find out you’re following a ketogenic diet, or maybe you’ve even wondered about it yourself. It’s hard to deny that keto is great for weight loss and reversing conditions like type 2 diabetes, metabolic syndrome, and more. But that doesn’t automatically imply that it’s safe to eat this way for the long term.

If you’re of a certain age, you’ll remember from back in the heydays of the Atkins diet that the prevailing opinion was, “Sure, you’ll lose weight, but you’ll just make a thinner corpse when you die from a heart attack!” 

But is this true? Is it safe to follow a keto diet for an extended period of time?

Asking the wrong question

Isn’t it funny that no one ever asks how long it’s “safe” to live with type 2 diabetes or a liver overloaded with fat? Or how long it’s safe to consume upwards of 80 grams of carbohydrate every morning in the form of cereal, juice, toast with jam, or a fruit smoothie?

Yet, remove sugar and starch from your diet and suddenly you or your loved ones start to wonder if what you’re doing is safe. We ask if it’s safe to eat very little carbohydrate without asking if it’s safe to eat a ton of it.

Remember: the type of safe, benign, beneficial nutritional ketosis induced by a ketogenic diet is a world apart from the dangerous state of ketoacidosis. Just because these both have “keto” in their names doesn’t mean they’re anything alike. (See this article on the critical differences between nutritional ketosis and ketoacidosis.)

Are you even in ketosis?

I hate to burst your bubble, but depending on what you typically eat, you might not even be in ketosis on your “keto” diet. For most people, carbohydrate intake needs to be very low in order to induce the state of ketosis.

If your diet includes substantial amounts of vegetables or products made with sugar alcohols, there’s a good chance that while your diet is low-carb, it might not be ketogenic. So you might be worrying about something that’s not even relevant for you.

(But that’s okay! Not everyone needs a strict ketogenic diet. If you’re happy with how you look and feel—including your physical and mental health—then whatever you’re doing now is working well for you and you don’t require an ultra-strict medical-type ketogenic diet. Like our friends at KetoGains say, “Chase results, not ketones.”)

Everyone differs in the amount of carbohydrate they can consume and still maintain a ketogenic state. As a general rule, most people need to keep carbs super low, especially if they’re a bit older and not very physically active. If you regularly include packaged foods like keto ice cream, cereal, cookies, and bars in your diet, then your carb intake is probably a lot higher than you think it is and you’re probably not in ketosis most of the time. 

Is ketosis unsafe?

Let’s say you are in ketosis most of the time. Why would someone think this isn’t safe to do for an extended period of time?

In the early days of therapeutic ketogenic diets when it was used primarily for children with epilepsy, it wasn’t just carbohydrates that were limited. Children following ketogenic diets were also instructed to limit their protein intake and also limit fluid intake.

These other restrictions resulted in problems such as kidney stones and growth stunting, but it’s important to understand that these were not caused by a very low carbohydrate intake. They were caused by the restrictions on protein and fluid intake. These limitations would likely result in growth stunting and kidney stones on any diet, not just keto.

So it wasn’t ketosis that was problematic; it was the way ketogenic diets were implemented. 

Fortunately, the research has come a long way in the more than a century since the advent of the ketogenic diet for epilepsy, and fluid restriction is no longer advised. Protein restriction also isn’t typically part of the “prescription,” although people who need the strictest form of keto in order to control an otherwise intractable medical condition may need to be meticulous about their “macros,” or getting specific amounts of protein and carbohydrate in their diet relative to the quantity of fat they eat.

Potential concerns

Just because a certain way of eating is beneficial for so many issues doesn’t automatically mean it’s perfect in all ways and that there’s no risk of adverse effects. There are some potential issues to be aware of if you follow a strict ketogenic diet for the long term. Past articles have covered the critical importance of getting enough electrolytes, dealing with keto flu, and what to do if you experience constipation or diarrhea on keto.

Beyond those basics, what about micronutrients? Will a strict ketogenic diet give you everything you need in terms of vitamins and minerals? Supplements are a touchy subject. Some folks who follow a strict carnivore diet claim that eating nothing but red meat and salt will result in excellent health and not lead to any inadequacies or deficiencies.

This may be true for some, but erring on the side of caution, don’t assume that keto (or carnivore) will give you everything you need. Consider taking a daily multivitamin/mineral complex, and if you’re experiencing any unpleasant issues, work with your doctor or a qualified nutrition professional to assess your diet and see if a micronutrient shortfall might be causing them.

If keto makes you feel mostly your best but there’s still a bit of room for improvement, don’t assume that you need to be stricter and cut out even more foods. It’s possible you need to add something—like vitamin C, magnesium, a B-complex, or even iron. (Yes, it’s possible to eat red meat and other iron-rich foods and still have a deficiency.)

Bottom line

How long is it safe to be in ketosis? For as long as you like, as long as you feel well and are satisfied with your state of health. Rather than asking how long it’s safe to follow a keto diet, people should be asking how long it’s safe to eat foods that skyrocket your blood sugar and insulin and keep you tethered to ceaseless hunger, sugar cravings, and intrusive thoughts of food all day.

For most people, keto makes these disappear or at least get much quieter. If you have concerns about your specific personal situation on a keto diet, there are listings where you can search for keto-friendly medical and nutrition professionals. Don’t go it alone when expert help is available.

Need a low-carb meal to keep you in ketosis?

Then check out Keto Chow! Keto Chow is a keto meal shake with 1/3 of your daily nutrients. It comes in 30+ different flavors and only takes seconds to make.