Ketogenic Diets and Psychiatric Medications

What you need to know before you go low carb.

Posted Mar 27, 2018

Suzi Smith, used with permission
Source: Suzi Smith, used with permission

If you take psychiatric medications and are thinking about trying a low-carb or ketogenic diet for mental health reasons, please read this article first.

Public interest in ketogenic diets is skyrocketing — and with good reason. These specially formulated very-low-carbohydrate (typically less than 25 grams per day), higher-fat diets can be life-changing for people with serious health conditions, such as type-2 diabetes, obesity, and epilepsy, and has shown promise for numerous other metabolic and neurological diseases. When something works this well, word spreads like wildfire.

In June 2017, I wrote an article for Psychology Today describing how ketogenic diets affect brain chemistry and summarizing the mental health studies we have so far. After posting that article, I received many questions on social media about the real-world aspects of trying low-carb diets — especially about how to manage psychiatric medications. While you’ll often hear the standard legal warning about always consulting first with your doctor before making any lifestyle change — from starting a new walking regimen to eating more kale — warnings about starting ketogenic diets are not to be taken lightly if you take medications.

Ketogenic diets cause profound shifts in brain and body chemistry rather quickly. These changes are almost always positive and healthy, but they can have a major impact on medication levels, dosages, and side effects that require close medical supervision, particularly in the first month or two while your metabolism adjusts to your new healthy way of eating.

Below I’ve listed the most important things you need to know if you currently take any medications for depression, anxiety, mood swings, sleep, attention, or psychosis, and you are considering trying a low-carb or ketogenic diet for the first time. It is not meant to be comprehensive, and each situation is unique, so please always consult with your own health-care provider for individualized advice. Many topics will be beyond the scope of this article, so if you are a newbie to keto, I recommend this excellent article — "A Ketogenic Guide for Beginners" on DietDoctor.com — written in everyday language that explains the nuts and bolts.

Before you start a low-carb/ketogenic diet for mental health purposes:

  • Discuss the idea with the psychiatrist or psychiatric nurse who prescribes your medications first, before making any changes to your diet.
  • Ideally, your prescribing clinician will be supportive of the idea and knowledgeable about ketogenic diets, or at least open to learning. If not, you may want to consider either finding a new prescriber or asking your current prescriber if they would be willing to collaborate with an experienced nutritionist, primary care clinician, or other health professional who can help guide them in your care.
  • Have some blood tests drawn before you change your diet, ideally after a 12-hour fast (water and medicines only). Tests I recommend include:
    • Fasting Comprehensive Metabolic Panel (glucose, electrolytes, kidney function, liver function, and acid-base balance)
    • Fasting Lipid Panel (includes HDL cholesterol and triglycerides)
    • Fasting Total Insulin Level
    • Any relevant medication blood levels (Lithium and Depakote are particularly important — see below)
    • Any other tests your clinicians recommend
  • Have your blood pressure, heart rate, and weight checked, and measure your waist circumference
  • Make a plan with your clinicians for close monitoring. Ideally, you’ll want once-a-week appointments with your prescriber, your therapist (if you see someone separately for counseling/support), and any other collaborating health professionals, especially during the first four to six weeks of your new diet.

Will the ketogenic diet help my mental health?

We don’t yet have enough scientific evidence to provide good statistics about this question, so there is only one way to find out — by trying the diet for yourself. It is possible that a ketogenic diet has a greater chance of helping people with mental health concerns who also happen to have insulin resistance, which is why I suggest some of the metabolic tests above.

When can I stop my medication?

If you are excited about trying a ketogenic diet in hopes that you may be able to reduce or eliminate one or more of your medications, that’s wonderful — but please be patient. Most medications should be continued until you’ve been solidly in ketosis for at least four to six weeks, which is the minimum amount of time it takes for the body to start using ketones (fat energy molecules) efficiently for fuel. At the six-week mark, you and your clinician can discuss whether it makes sense to begin considering any reductions, but for many people, three months may be a more reasonable reflection point.

How do I stop my medication safely?

Once you’ve adapted nicely to your ketogenic diet, depending on how you’re feeling, you and your clinician may decide to work toward possible medication reductions. Never stop any medicine abruptly! Always collaborate with your clinician, taper down very slowly, and change only one medicine at a time! Many psychiatric medicines can cause uncomfortable or even potentially dangerous withdrawal effects if not tapered slowly and carefully.

If you do well tapering off one medication, keep in mind that it can take up to six weeks for the brain effects of most psychiatric medications to completely reverse themselves. For this reason, if you are taking more than one psychiatric medication, it may be wise to wait at least six weeks in between each medication taper. For example: if you finish taking an antidepressant such as Zoloft in early May, you won’t know for sure how you’re actually feeling without it until at least late June. If you start to taper a second medication during that six-week window, and your depression symptoms begin to return, you won’t know whether it is because the Zoloft benefits are wearing off, or because you’ve begun tapering a second medicine.

When will I start feeling better?

I am sorry to be the bearer of bad tidings, but your mood may actually get worse before it gets better. Irritability, low energy, mood swings, sleep changes, and cravings for sweets and starches are among the possible “withdrawal” effects, particularly if your diet was very high in refined carbohydrates, like sugar and flour, before you embarked on your ketogenic journey. In most cases the first few days are usually the hardest, but some people need more time to transition. During the first week or two, it’s best if you have good people around who know you well, who can support you through the rough patches. If you feel unsafe, out of control, or just plain miserable for too long, don’t be a hero. This diet is not for everyone, and you may want to consider other healthy lifestyle changes first — perhaps most importantly, removing all processed “foods.” My top ten (non-keto) recommendations can be found in my article: "Top Ten Tips for a Healthier Brain in 2018." 

Are some psychiatric medications more difficult to take on a ketogenic diet?

YES. Most psychiatric medications don’t pose any special problems on a ketogenic diet, but there are very important exceptions, detailed below.

Antipsychotic medications and ketogenic diets

Antipsychotic medications, such as Risperdal, Abilify, and Seroquel, can increase insulin levels in some people and contribute to insulin resistance, which can make it harder for your body to turn fat into ketones. In some cases, these medicines may eventually need to be lowered or gradually stopped before you can realize the full potential benefits of a healthy ketogenic diet. There are many medicines that fall into the “antipsychotic” category, and they are frequently prescribed for non-psychotic conditions, such as depression, bipolar disorder, or severe anxiety. New medicines are being added to this category all the time, so if you’re not sure whether your medicine is an antipsychotic, check with your prescriber.

Lithium and ketogenic diets

During the first few days of a ketogenic diet, most people will lose a few pounds of excess water weight through urination because ketogenic diets change the way the body processes fluid and salt. Water loss during the early phase of low-carb can cause lithium to become more concentrated in the blood, and lithium blood levels may rise. If you and your clinician notice lithium side effects emerging that you didn’t have before (these include excessive thirst, difficulty concentrating, sluggishness, tremors, and poor coordination) the dosage may need to be adjusted downward. It is always best to have a lithium blood level checked before embarking on a ketogenic diet and to recheck it if any side effects emerge to see if the dosage needs to be lowered. It is very important to consume plenty of salt and pay attention to electrolytes like magnesium and potassium as well, particularly during the early phase of this diet.

Anticonvulsant mood stabilizers and ketogenic diets

Many anticonvulsant medications originally designed to control epilepsy (seizures) are also prescribed by psychiatrists for mood swings, insomnia, or anxiety. The ones most likely to behave strangely when embarking on a ketogenic diet are Depakote (valproate), Zonegran (zonisamide), and Topamax (topiramate).

Depakote (valproate or valproic acid) is actually a fatty acid that can be burned by your cells for fuel! Since your body ramps up fat metabolism on a ketogenic diet, cells hungry for fat can remove Depakote molecules from your bloodstream, which can cause Depakote blood levels to fall. If this happens, you may feel as though Depakote isn’t working as well as it did before you changed your diet. In some cases, the dosage of Depakote may need to be increased temporarily as you adjust to a ketogenic diet. This is why it’s so important to have a blood test for Depakote levels before starting the diet, so that if you notice any problems along the way, the blood level can be rechecked and the dosage adjusted accordingly.

Zonegran (zonisamide) and Topamax (topiramate) are very similar anticonvulsant medicines. Both of them change the way the kidney processes certain electrolytes and cause the blood pH to become a little more acidic (metabolic acidosis), and can therefore increase risk for kidney stones. Ketogenic diets have very similar effects on kidney electrolyte processing — they also make the blood a little more acidic (ketones are acidic) and can slightly increase risk for kidney stones in some individuals, so people taking Zonegran or Topamax may be at even higher risk for kidney stones on a ketogenic diet than others are. If you take either of these medicines, it is particularly important to stay well-hydrated to reduce your risk for kidney stones. The other common recommendation for people taking Zonegran or Topamax who want to reduce kidney stone risk is to eat a low-salt diet. This may not be a good idea on a ketogenic diet, especially during the early adjustment period. Therefore, embarking on a ketogenic diet while taking one of these medicines is tricky and must be carefully considered with your health care professionals.

Blood pressure medications and ketogenic diets

Clonidine, Prazosin, and Propranolol were originally designed to treat high blood pressure, but they are also sometimes prescribed for insomnia, anxiety, nightmares, or ADHD. In the early stages of starting a ketogenic diet, blood pressure may decrease as the body lets go of excess fluid. This can be a very healthy change, particularly if you have high blood pressure. However, if you are taking a blood pressure medicine, your blood pressure could fall too low, putting you at potential risk for lightheadedness, dizziness, and fatigue, with the worst-case scenario being that you could even pass out. Many other psychiatric medications also carry a small risk of lower blood pressure, including all antipsychotic medications (Zyprexa, Latuda, Geodon, etc) and SSRI antidepressants (Zoloft, Lexapro, Prozac, etc). This is why it’s good to have your blood pressure monitored along the way when trying a ketogenic diet. Blood pressure medicines may need to be reduced or stopped on a ketogenic diet.

Constipation and psychiatric medications on ketogenic diets

Some people will experience constipation on a ketogenic diet. Many psychiatric medications can also cause constipation, so the combination of medication plus the diet can tip some people over the edge into severe constipation. Often this is temporary, and there are many ways to troubleshoot it and improve the situation, but it is important to be aware of this possibility.

Other health conditions and non-psychiatric medications

If you have any health problems or take any non-psychiatric medications, it is just as important to work closely with your primary care clinician around those issues. You can find a list of some things to be aware of in this article: "Is the Ketogenic Diet Safe for Everyone?"

Should you try a ketogenic diet?

While I am convinced of the potential benefits of a ketogenic diet and eat a ketogenic diet myself, I would encourage you to make some simpler changes to your diet first to see how much better you might feel (see: "Top Ten Tips for a Healthier Brain in 2018"). Those changes alone may allow you to reduce your need for medications without having to contend with ketosis adjustment issues at the same time. The less medication you are taking when you start a ketogenic diet, the better. If the changes recommended in the this post do not help enough, and/or if you have insulin resistance, then a ketogenic diet is well worth exploring.

The bottom line: If you take psychiatric medications, it is critically important to educate yourself, plan ahead, and work closely with your mental health providers before embarking on a ketogenic diet.       

More Posts