Although "keto flu" symptoms are commonly experienced by people transitioning to a lower carbohydrate diet, if you ever feel unwell when following a ketogenic diet, you must pause it and see your care provider.
If you are around 30-40 grams or lower per day, you should be able to start the challenge without discomfort, however still monitor your body's response closely in the first week or two. You should NOT be feeling any discomfort or symptoms if you are hydrating with sodium, bone broth, and easing your carbs down GRADUALLY, week by week. Before going on a ketogenic diet, you should first discuss it with your doctor and make sure that it is a safe and healthy option for you. Ketogenic diets are not beneficial for everyone (see medical conditions which are contraindicated with ketogenic diets below, and do your research before trying a low carb or keto diet which is very restrictive in carbohydrates). In some cases, low blood sugar can result in adverse reactions (with diabetics in particular) so caution and proper doctor supervision and permission must be sought when making any drastic dietary changes.
If you follow these 4 quick steps, you will likely avoid any keto flu symptoms:
1. You must have a health screening and bloodwork done before going low carb or keto to rule out any health conditions such as insulin resistance or pre-diabetes, gall stones, kidney issues or any other health conditions which would make keto unpleasant & unsafe for you or unsafe without close doctor supervision. You must consult your doctor before starting a lowered carb or keto diet to make sure that it s suitable for you and that there are no contraindications for keto or low carb if you’re currently taking any medication.
2. Are you brand new to low carb and keto or are you doing low carb at the moment? What is your current carb intake? It’s important to first determine your current carb intake so that you may gradually lower it over time to avoid any Keto flu symptoms when trying a keto diet. If you are not sure of your current carb intake, you may use a food tracker such as My Fitness Pal and enter in one average day's food intake to see what your carb intake is at the moment. If your carb intake per day is over 40 g per day total, you will need to gradually move to keto, and if over 80 g per day then you will need several weeks to prepare. If you are around 30-40 grams or lower per day, you should be able to start the challenge without discomfort, however still monitor your body's response closely in the first week or two. You should NOT be feeling any discomfort or symptoms if you are hydrating with sodium, bone broth, and easing your carbs down GRADUALLY.
3. During the first phases of eating a lower carb or ketogenic diet and before starting the meal plans or 28 day challenge, you must gradually reduce your carb intake over 2-6 weeks before day 1 of the challenge in order to avoid keto flu symptoms. You may have to reduce your carbohydrate consumption slowly over a longer period of time to minimize any potential reactions, but eventually, by continuing to consume a diet lower in high carb foods you should be able to avoid any keto flu or hypoglycemic reactions.
What exactly is the “Keto flu”?
During the beginning stages of the ketogenic diet, its common to begin feeling “bogged down”. Due to ketogenic processes happening in your body, this abnormal feeling is to be expected. However, it must not be sustained due to prolonged exposure to circulating ketones.
The “keto flu” is a feeling of flu-like symptoms due to your muscles and organs not being able to function optimally due to circulating ketones generated by the ketogenic diet. It may also be related to hypoglycemia or low blood sugar (see below). Common symptoms include lightheadedness, nausea, fatigue, mental fogginess, abdominal cramps, headaches, and diarrhea.
How long does it last?
It really depends. However, Keto flu symptoms can begin to appear as early as 1-2 weeks into the ketogenic diet and will remain as long as ketosis is occurring. If symptoms become uncomfortable or interfere with daily routines, the ketogenic diet should be stopped and carbohydrates are to be reintroduced.
Hypoglycemic reactions may occur if your blood sugar drops too low too fast. In making sure that you know how to make the transition from high carb to low carb or keto without experiencing any symptoms, making the switch smooth and easy. Hypoglycemia symptoms can be experienced as the "keto flu" and may include:
- Sweating, chills and clamminess.
- Irritability or impatience.
- Confusion, including delirium.
- Rapid heartbeat.
- Hunger and nausea.
High carbohydrate intake surges blood glucose levels in the body, which increases the production of insulin to counter these elevated levels and use it as energy required for everyday functioning. A habit of high carbohydrate intake will create continuously elevated blood insulin levels. When we start the transition to a low carb diet, the body has more insulin and therefore, the glucose that is already low due to a low carb intake, further slides down and can generate hypoglycemia. Ketogenic diets in particular are VERY restrictive of carbohydrates. The dramatic reduction in cabs can cause what is know as “insulin reactions” or “insulin shock”, which are other terms for hypoglycemia and symptoms can be anything from mild to more severe.
Transient Hypoglycemia (THG)
Hypoglycemia symptoms occur when blood glucose levels fall below 70 mg/dl but some people may start to have symptoms of hypoglycemia even when their blood glucose levels are higher than 70 mg/dl. This can happen when your blood glucose levels are very high and start to go down quickly. It usually happens when you start following a strict low carb diet without acclimatizing your body to the new regimen. THG automatically vanishes when body starts adopting to alternate energy sources like fats in a ketogenic state.
Reactive hypoglycemia (RHG)
It is a stimulus-response situation as the name suggests. When you eat a very high carb meal, body produces even higher insulin to balance the blood glucose. Sometimes, the elevated insulin levels do not normalize after the meal and drive the blood glucose levels very low. This phenomenon is RHG.
Ketogenic Diets & Hypoglycemia
Ketogenic diets lower the average blood sugar and insulin levels. However, it takes some time for the body to come out of high-carb & high-insulin mode. By lowering carb intake, your body will turn to burning fat instead of carbohydrates for energy needs, once it has used up all available and store glucose from a standard high carb diet.
It takes anywhere from 2-5 weeks for the body to adjust to the lowered carb intake, and produce the enzymes needed to burn fat. During this adjustment phase, your body is still secreting more than enough insulin for the previous, higher level of carbohydrate intake. In this period you may experience occasional episodes of hypoglycemia and hence, it is important to know how to recognize it and pause low carb or see your cre provider.
Treatment of Hypoglycemia
The American Diabetic Association recommends following treatment measures if and when experiencing symptoms of hypoglycemia:
- Consume 15-20 grams of glucose or simple carbohydrates
- After 15-20 minutes, if hypoglycemia persists, repeat.
- Once blood glucose returns to normal, eat a small snack if your next planned meal or snack is more than an hour or two away.
15 grams of simple carbohydrates commonly used:
- Glucose tablets (follow package instructions)
- 1-2 servings of fruit
- 4 ounces (1/2 cup) of juice or regular soda (not diet)
- 1-tablespoon honey
- 8 ounces of nonfat or 1% milk
Ideal Transition (Making sure you avoid hypoglycemia)
The first few weeks are important when you switch to a keto diet. You are more likely to experience the side effects of changes in dietary habits. In the short term, the easiest way to avoid hypoglycemia is to eat every 3-4 hours. In the long term, a keto diet itself is the best way to eliminate any hypoglycemic symptoms caused by high sugar diets.
My personal experience taught me that it is important to go down in carbs gradually, especially if you are new to low carb lifestyle. People who are already doing low carb will do better switching to a Ketogenic diet. However, even for them, it is still important to graduate slowly from 50-200 g per day of carb down to 20-30 g. The process should take several weeks by decreasing carbs slowly by 5-10 g or so per day and not rushing the transition.
Gradually reducing carb intake over time should be beneficial in most people. In my opinion, the transition period should be anywhere between 5 to 9 weeks, depending upon individual response.
Back to the keto flu. What exactly is happening during the Keto flu?
When undergoing the ketogenic diet, your body does not have much, if any, carbohydrates in circulation. Therefore, your body uses its secondary source of energy, fat tissue. When fat tissue breaks down into useable energy, known as “ketone bodies”, and enters blood circulation, it brings along with it it’s acidic properties. Ketones are acidic in nature and will lower your blood pH. This acidic state will put strain on your organs as long as ketones are in abundant circulation.
What can I do about it?
The good thing about ketone bodies, is that they’re easily excreted through your kidneys. However, kidneys need plenty of water to do their job. If following the ketogenic diet, you will need to consume at LEAST 3 liters of water per day (4 liters if you exercise regularly).
In general, the kidney does a fantastic job at regulating electrolyte levels in the body, provided it has enough water to do its job. However, drinking excess water to flush out ketones may result in loss of important electrolytes as well.
How do I replenish the electrolytes I lost?
Easy. Simply replenish what you lost. During kidney clearance, the most important electrolytes lost will be sodium, potassium, magnesium and chloride.
By adding a high quality sodium such as sea salt to meals, your body can replenish electrolytes.
It is important to only get potassium from food sources and not take any potassium supplements unless provided by your doctor.
The following foods are a great start to replenishing potassium levels:
-Avocados contain potassium, monounsaturated fats (known to lower LDL cholesterol levels), and vitamin C. They work great in salads, eggs, and as a substitute for butter if avoiding dairy.
-Wild salmon contains potassium and Is a great source of quality protein. Additionally, it’s loaded with omega-3 fatty acids, which can lower the risk for heart disease and stroke.
-Spinach is nutritious and versatile. Not only does it contain adequate amounts of potassium, but it’s also high in vitamins and K, as well as magnesium and iron. All of these components play an integral role in bodily functions.
-Bok choy is a type of Chinese cabbage that is low in carbohydrates and contains potassium, vitamins C and K, and insoluble fiber. It is versatile and used in a range of dishes from salads to stir-frys.
Most meals you prepare will likely require some form of salt, also known as “sodium chloride”. The ketogenic diet naturally produces diuresis (kidney excretion), so no need to severely restrict salt intake as long as water consumption is appropriate. Bone broth is a great way to add sodium to your system. Not only does it contain adequate amounts of sodium, and can include magnesium, but also tastes great and can be used in a variety of dishes.
Who is the ketogenic diet NOT recommend for?
Before beginning any new diet or exercise regimen, always consult your local general practitioner.
Due to the effect of acidifying the bloodstream, anyone with the following conditions are advised NOT to follow the ketogenic diet:
-Any stage of pregnancy
-Anyone with decreased kidney function
-All type 1 diabetics (recommended for type 2 diabetics without kidney damage and under doctor supervision)
-Anyone on medications that decrease kidney or liver function (i.e. metformin). Keto must be discussed with your physician if you are on any kinds of medications or drugs to ensure there are no contraindications with keto
-Women with irregular menses
-Anyone with a current or previous eating disorder
-Anyone with chronic respiratory conditions (COPD and other restrictive lung diseases)
Those who experience the keto flu may believe they are doing something wrong. This is false. Keto flu symptoms are an indication that you are gaining independence from carbohydrates as an energy source and that ketosis is occurring. Proper hydration and electrolyte supplementation with sodium is very important to support the your organs as they flush ketone bodies out of your system and so that you are able to replenish lost electrolytes. If you experience low blood sugar symptoms, pause the ketogenic diet and consume carbohydrates using the tips above.
Although "keto flu" symptoms are commonly experienced by people transitioning to a lower carbohydrate diet, if you ever feel unwell when following a ketogenic diet, you must pause it and see your care provider. Before going on a ketogenic diet, you should first discuss it with your doctor and make sure that it is a safe and healthy option for you. Ketogenic diets are not beneficial for everyone (see medical conditions which are contraindicated with ketogenic diets below, and do your research before trying a low carb or keto diet which is very restrictive in carbohydrates). In some cases, low blood sugar can result in going unconscious in some individuals (diabetics in particular) so caution and proper doctor supervision and permission must be sought when making any drastic dietary changes.