Here are a few of the most common side effects that I come across when people first start keto. Frequently the issues relate to dehydration or lack of micronutrients (vitamins) in the body. Make sure that you’re drinking enough water (close to a gallon a day) and eating foods with good sources of micronutrients. To read more on micronutrients, click here >
Hi, I'm Amanda. I’ve been cooking primal keto and lactopaleo recipes for over a decade, and have developed recipes for top nutrition coaches and ketogenic meal subscription boxes. I'm the author of Keto Life (a guide) and the best-selling Wicked Good Ketogenic Diet Cookbook (a cookbook). Ever heard the phrase,"never trust a skinny chef"? Well, consider me super trustworthy. I will probably never be "skinny," and that’s OK because I’m not here to teach you how to lose weight, my goal is to provide you with awesome recipes. I absolutely adore the ketogenic lifestyle, and it has helped me overcome a number of health issues. I hope my recipes help you do the same, while eatin’ good!

Yes you can lose fat on a low carb because it’s just another low calorie diet. How do I know this? I’ve done low carb, (Atkins, etc) high carb, (Slimming Word) moderate carb etc and log my food and was shocked each time to see they were all low calorie. After the initial week or so the rate of fat loss is same as any other diet. It’s calories in calories out. Simple. It’s what some call indirect deficit diet placing silly restriction, rules can eat must eat etc. and of course you lose weight but nothing to do with low carb. It works because it’s a low calorie diet.
A keto diet has shown to improve triglyceride levels and cholesterol levels most associated with arterial buildup. More specifically low-carb, high-fat diets show a dramatic increase in HDL and decrease in LDL particle concentration compared to low-fat diets.3A study in the long-term effects of a ketogenic diet shows a significant reduction in cholesterol levels, body weight, and blood glucose. Read more on keto and cholesterol >
Even in endurance sports that don’t require sprinting, ketogenic-style diets are disadvantageous according to a ketogenic diet and exercise article published in Sports Medicine[5]: “a high-fat, low-carbohydrate ketogenic diet may impair exercise performance via reducing the capacity to utilize carbohydrates, which forms a key fuel source for skeletal muscle during intense endurance-type exercise.” The article concluded, “At present there are no data available to suggest that ingestion of ketone bodies during exercise improves athletes’ performance under conditions where evidence-based nutritional strategies are applied appropriately.”
When you’re eating the foods that get you there (more on that in a minute), your body can enter a state of ketosis in one to three days, she adds. During the diet, the majority of calories you consume come from fat, with a little protein and very little carbohydrates. Ketosis also happens if you eat a very low-calorie diet — think doctor-supervised, only when medically recommended diets of 600 to 800 total calories.
When you eat less than 50 grams of carbs a day, your body eventually runs out of fuel (blood sugar) it can use quickly. This typically takes 3 to 4 days. Then you’ll start to break down protein and fat for energy, which can make you lose weight. This is called ketosis. It's important to note that the ketogenic diet is a short term diet that's focussed on weight loss rather than the pursuit of health benefits. 

So rather than giving one-size-fits-all dietary advice or weaponizing the word “balanced” it might be better if the medical community suggested that there are Individual differences that need to be considered. This might also help those lay folk who have had success with one dietary lifestyle or another also realize that what’s valid for them may not be good advice for others.
A Cochrane systematic review in 2018 found and analysed eleven randomized controlled trials of ketogenic diet in people with epilepsy for whom drugs failed to control their seizures.[2] Six of the trials compared a group assigned to a ketogenic diet with a group not assigned to one. The other trials compared types of diets or ways of introducing them to make them more tolerable.[2] In the largest trial of the ketogenic diet with a non-diet control[16], nearly 38% of the children and young people had half or fewer seizures with the diet compared 6% with the group not assigned to the diet. Two large trials of the Modified Atkins Diet compared to a non-diet control had similar results, with over 50% of children having half or fewer seizures with the diet compared to around 10% in the control group.[2]
Yancy has seen similar results in his practice. “Carbohydrate intake is the main driver of blood sugar. So if you’re able to lower blood sugar by reducing carbohydrate intake, then you may be able to reduce diabetes medication,” he says. “We’ve seen people come off of hundreds of units of insulin just by changing the way they eat, and that can happen really quickly, in just a few weeks.”
Even after irradiation (the industry standard sterilization process that also destroys any antioxidants and health benefits), spices and herbs can spoil in your home, and often harbor aggressive mold toxins. To spice up your dishes the Bulletproof way, use high-quality, fresh or recently opened herbs and spices. Spices with especially high mold toxin risk include black pepper, powdered garlic, nutmeg, and paprika. Apple cider vinegar is the only vinegar permitted in the Bulletproof diet, as other vinegars and yeasts introduce toxins, and promote yeast growth in your gut.
Even in endurance sports that don’t require sprinting, ketogenic-style diets are disadvantageous according to a ketogenic diet and exercise article published in Sports Medicine[5]: “a high-fat, low-carbohydrate ketogenic diet may impair exercise performance via reducing the capacity to utilize carbohydrates, which forms a key fuel source for skeletal muscle during intense endurance-type exercise.” The article concluded, “At present there are no data available to suggest that ingestion of ketone bodies during exercise improves athletes’ performance under conditions where evidence-based nutritional strategies are applied appropriately.”

Upon starting the diet, some patients report symptoms like fatigue, headaches, and muscle aches. However, these short-lived symptoms are, in fact, a sign that the diet is working, and the body is switching over from burning glucose as fuel to burning fat. This transition involves upregulating certain enzymes and down-regulating others; it is a profound shift for the human body that can have uncomfortable symptoms. However, these side effect usually last only 3-4 weeks. They can be ameliorated in most cases, by drinking several cups of bouillion broth during the day until the transition is completed.15
For many people, one of the more surprising side effects of starting a ketogenic diet is a bout with the “keto flu.” How so? “When you go on this diet, your kidneys don’t retain as much salt or water, which can lead to flu-like symptoms, such as fatigue and headache, or constipation,” says Laura Saslow, PhD, an assistant professor at the University of Michigan School of Nursing. “But these are typically short-lived symptoms that can be prevented or treated by increasing your salt and water intake.” However, if you have high blood pressure, speak with your doctor before adding more sodium to your diet. And know that the keto flu only lasts a week or two; symptoms typically subside once the body adjusts to the diet.
Even in endurance sports that don’t require sprinting, ketogenic-style diets are disadvantageous according to a ketogenic diet and exercise article published in Sports Medicine[5]: “a high-fat, low-carbohydrate ketogenic diet may impair exercise performance via reducing the capacity to utilize carbohydrates, which forms a key fuel source for skeletal muscle during intense endurance-type exercise.” The article concluded, “At present there are no data available to suggest that ingestion of ketone bodies during exercise improves athletes’ performance under conditions where evidence-based nutritional strategies are applied appropriately.”
No deep fryers or air fryers needed for these wings! Forget those greasy chicken wings you’d order at a restaurant and opt-in for these homemade guiltless garlic parmesan wings. You won’t find rancid vegetable oil, gluten or a deep frier here — just avocado oil, healthy pecorino romano and free-range, organic chicken for a twist on an otherwise unhealthy classic.

I actually clicked on the story just to see if they included anything about it’s use in managing chronic migraine. I have chronic migraine, basically intractable. Nothing has helped. I’ve tried medications, meditations, and everything in between including a bunch of dietary changes. Keto is my next consideration. I’m happy to hear it helped you! Thanks for sharing
The ketone bodies are possibly anticonvulsant; in animal models, acetoacetate and acetone protect against seizures. The ketogenic diet results in adaptive changes to brain energy metabolism that increase the energy reserves; ketone bodies are a more efficient fuel than glucose, and the number of mitochondria is increased. This may help the neurons to remain stable in the face of increased energy demand during a seizure, and may confer a neuroprotective effect.[56]
Early studies reported high success rates; in one study in 1925, 60% of patients became seizure-free, and another 35% of patients had a 50% reduction in seizure frequency. These studies generally examined a cohort of patients recently treated by the physician (a retrospective study) and selected patients who had successfully maintained the dietary restrictions. However, these studies are difficult to compare to modern trials. One reason is that these older trials suffered from selection bias, as they excluded patients who were unable to start or maintain the diet and thereby selected from patients who would generate better results. In an attempt to control for this bias, modern study design prefers a prospective cohort (the patients in the study are chosen before therapy begins) in which the results are presented for all patients regardless of whether they started or completed the treatment (known as intent-to-treat analysis).[19]
When you eat tons of carbs, your blood sugar is consistently elevated, and then so is insulin. Insulin is a hormone that keeps your blood sugar in check by shuttling the glucose into cells, but when there’s a consistently high amount of insulin, your cells become resistant. This insulin resistance makes it easier to store fat, and chronically high levels of insulin also cause excessive inflammation in the body, which contributes to heart disease, high blood pressure, and potentially type 2 diabetes.
The original therapeutic diet for paediatric epilepsy provides just enough protein for body growth and repair, and sufficient calories[Note 1] to maintain the correct weight for age and height. The classic therapeutic ketogenic diet was developed for treatment of paediatric epilepsy in the 1920s and was widely used into the next decade, but its popularity waned with the introduction of effective anticonvulsant medications. This classic ketogenic diet contains a 4:1 ratio by weight of fat to combined protein and carbohydrate. This is achieved by excluding high-carbohydrate foods such as starchy fruits and vegetables, bread, pasta, grains, and sugar, while increasing the consumption of foods high in fat such as nuts, cream, and butter.[1] Most dietary fat is made of molecules called long-chain triglycerides (LCTs). However, medium-chain triglycerides (MCTs)—made from fatty acids with shorter carbon chains than LCTs—are more ketogenic. A variant of the classic diet known as the MCT ketogenic diet uses a form of coconut oil, which is rich in MCTs, to provide around half the calories. As less overall fat is needed in this variant of the diet, a greater proportion of carbohydrate and protein can be consumed, allowing a greater variety of food choices.[4][5]
Epilepsy is one of the most common neurological disorders after stroke,[7] and affects around 50 million people worldwide.[8] It is diagnosed in a person having recurrent, unprovoked seizures. These occur when cortical neurons fire excessively, hypersynchronously, or both, leading to temporary disruption of normal brain function. This might affect, for example, the muscles, the senses, consciousness, or a combination. A seizure can be focal (confined to one part of the brain) or generalised (spread widely throughout the brain and leading to a loss of consciousness). Epilepsy can occur for a variety of reasons; some forms have been classified into epileptic syndromes, most of which begin in childhood. Epilepsy is considered refractory (not yielding to treatment) when two or three anticonvulsant drugs have failed to control it. About 60% of patients achieve control of their epilepsy with the first drug they use, whereas around 30% do not achieve control with drugs. When drugs fail, other options include epilepsy surgery, vagus nerve stimulation, and the ketogenic diet.[7]
All of our diets are developed with each individual child in mind. We focus on what the child likes to eat and try as much as possible to incorporate their favorite foods into their diets, and many children actually enjoy their keto food. Even if your child is already on a special diet due to allergies or food intolerances, our team can still incorporate these special needs into your child's ketogenic diet.
Note: Are you a vegetarian or vegan and want to go on a ketogenic diet? It’s still possible! Just keep in mind that the dietary restrictions can sometimes be a little bit intense. Make sure to plan ahead and prepare to aid your success. To help out, we’ve published articles (with 7 day meal plans included) for both the vegetarian ketogenic diet and the vegan ketogenic diet.
Dehydration. With fewer water-binding carbohydrates in the diet, the body is less able to hold onto fluids, which can lead to dehydration. Eating more salt can help offset this, but it can also raise blood pressure, creating a whole new set of issues. If you plan to follow a keto diet, hydration is key. To know how many ounces of fluid you need each day, Yancy recommends dividing your body weight in half. Then think of the resulting number as your daily fluid goal in ounces. So if you weigh 200 pounds, strive for 100 ounces of water a day.
Look, the good doctor is right – he only forgot to stress “portion control” which is why many fanatical dieters are so kee-jerk reactive to any discussion – odds are you over ate like a hog before your keto diet, and are weak and insecure in your diet plans. Eat EVERYTHING in small amounts, and you will live long and prosper. The only thing to avoid are processed foods. Cook your meals from scratch using quality ingredients.
The only issue with keto, is really that I’m afraid that it might be hard to up my calories to a maintenance weight now that I’ve gotten a taste preference for the rich assortment of foods with no carbs in them. I’m satisfied with less calories than I will need after my excess fat is burned off… but , maybe I bet my body will send more hunger signs once there isn’t anymore body fat in the cupboard to use instead of what goes down my throat.

A Cochrane systematic review in 2018 found and analysed eleven randomized controlled trials of ketogenic diet in people with epilepsy for whom drugs failed to control their seizures.[2] Six of the trials compared a group assigned to a ketogenic diet with a group not assigned to one. The other trials compared types of diets or ways of introducing them to make them more tolerable.[2] In the largest trial of the ketogenic diet with a non-diet control[16], nearly 38% of the children and young people had half or fewer seizures with the diet compared 6% with the group not assigned to the diet. Two large trials of the Modified Atkins Diet compared to a non-diet control had similar results, with over 50% of children having half or fewer seizures with the diet compared to around 10% in the control group.[2]
Upon starting the diet, some patients report symptoms like fatigue, headaches, and muscle aches. However, these short-lived symptoms are, in fact, a sign that the diet is working, and the body is switching over from burning glucose as fuel to burning fat. This transition involves upregulating certain enzymes and down-regulating others; it is a profound shift for the human body that can have uncomfortable symptoms. However, these side effect usually last only 3-4 weeks. They can be ameliorated in most cases, by drinking several cups of bouillion broth during the day until the transition is completed.15

When your body burns its stores of fat, it can be hard on your kidneys. And starting a ketogenic diet -- or going back to a normal diet afterward -- can be tricky if you’re obese because of other health issues you’re likely to have, like diabetes, a heart condition, or high blood pressure. If you have any of these conditions, make diet changes slowly and only with the guidance of your doctor.
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