
Normally your body runs on different fuel sources, including glucose from carbs. But when your carbs drop down to about 20 to 50 g a day, and you bump up your fat to 78% of your calories, your liver starts breaking down fatty acids into ketone bodies, a state called nutritional ketosis. On this diet, protein stays moderate, around 15 to 20%. Hey everyone, welcome back to the channel. Today we're tackling the ketogenic diet. What it is, what to eat and to avoid, what it's been studied for, potential side effects, and nutrients you probably need to supplement if you're on this diet. Well, let's get into it. The ketogenic diet, what is it really? Well, it's a high-fat, very low-carbohydrate eating pattern that changes how your body produces and uses energy. Normally your body runs on different fuel sources, including glucose from carbs. But when your carbs drop down to about 20 to 50 g a day, and you bump up your fat to 78% of your calories, your liver starts breaking down fatty acids into ketone bodies, a state called nutritional ketosis. On this diet, protein stays moderate, around 15 to 20%. Since excess protein can convert into glucose and kick you out of ketosis. This isn't a new fad, it was first used in the 1920s for the treatment of epilepsy, but now it's one of the most well-studied diets in medicine. Let's review what foods you can eat. On the ketogenic diet, you're eating foods that are naturally rich in fat and very low in carbs. That includes meats and poultry, fatty fish and seafood like salmon, sardines, tuna, eggs, and full-fat dairy. Dairy products such as cheese, butter, heavy cream, and plain Greek yogurt used in moderation. For vegetables, stick with non-starchy options like leafy greens, broccoli, cauliflower, zucchini, also asparagus, peppers, and cucumbers. Nuts and seeds like almonds, walnuts, and chia seeds are great, too, along with healthy fats like olive oil, coconut oil, avocado oil, and of course avocados. For drinks, stick with water, plain coffee, unsweetened tea, and sparkling water. The big theme is whole, minimally processed foods that keep you full without pushing your carbs too high. Now, let's talk about the foods to avoid. On the flip side, foods that you need to limit or cut out, since even small amounts of carbs can knock you out of ketosis. This includes grains and starches. For example, you know the breads, pastas, rice, oats, cereal. Sugary foods and sweets obviously have to go, too. And here's one that surprises people. Most fruits on this diet are off the table, since bananas, apples, oranges, and grapes are too high in natural sugar. Some people allow a small portion of berries here and there, but that's about it. Starchy vegetables like potatoes, corn, peas, they're out, along with legumes like beans and lentils. Also, watch out for low-fat or diet products, too, since manufacturers often add sugar to make up for the missing fat. Sugary drinks and alcohol, especially beer and sweet mixed drinks, are also off the table. My advice, read labels carefully. Carbs hide in a lot of packaged foods that don't even taste sweet. So, what conditions has the ketogenic diet been studied for? Let's get into the research. The ketogenic diet has been studied for several medical conditions, with evidence ranging from really solid to still emerging. First, epilepsy. The strongest evidence we have is for epilepsy. A landmark trial in the Lancet Neurology journal found that after 3 months, 30% of children on the ketogenic diet had more than a 50% reduction in seizures compared to just 6% in the control group. That's pretty outstanding. Updated clinical guidelines still recommend as a well-validated option for drug-resistant epilepsy. Next is type 2 diabetes and for blood sugar control. A randomized crossover study in the American Journal Clinical Nutrition followed 40 adults with prediabetes or type 2 diabetes through both a ketogenic diet and a Mediterranean style diet, 12 weeks of each. Both improved blood sugar, but the keto diet showed more consistent gains in fasting insulin and triglycerides or fats in the blood. And a 2024 meta-analysis of 29 trials found significant reductions in fasting glucose, A1C, insulin resistance, and triglycerides again with a ketogenic approach. Now, let's talk about obesity and weight management, which also ties into blood sugar control. A randomized controlled trial in the journal Nutrients compared a healthy ketogenic diet to a standard calorie restricted diet in 80 adults with obesity over 6 months. And the ketogenic group had greater reductions in weight, body mass index, and visceral fat. A 2022 meta-analysis backed this up, showing better improvements in weight, blood sugar, and cholesterol for overweight people with type 2 diabetes. Hey everybody, I want to take just a quick moment and invite you to my website drstengler.com. Here we have the supplements that we've been using with our patients for many, many years. High-quality and high-potency supplements, very pure. So, if you're looking for high-quality supplements where you can notice a difference both in how you feel on your lab tests, go to our website at drstengler.com. Now, one that doesn't get talked about enough is non-alcoholic fatty liver disease, abbreviated NAFLD, now sometimes called or abbreviated MASLD. And it affects around 30 to 38% of the global population. A study in the Proceedings of the National Academy of Sciences found that just 6 days, only 6 days of a ketogenic diet reduced liver fat by 31% and cut down liver insulin resistance by 58% despite only a 3% drop in body weight. And other studies have shown that a low-carb ketogenic diet is also good for fatty liver, improving liver fat, inflammation, and even a trend towards less scar tissue of the liver. A 2024 review summed up well that the ketogenic diet seems to hit multiple drivers of fatty liver all at once. Then there's also research into neurological conditions like Alzheimer's, Parkinson's, and traumatic brain injury based on idea that the brain can use ketones for fuel when it struggles with glucose. One randomized double-blind trial found that a ketogenic medical food improved cognitive function in some Alzheimer's patients, especially those without a genetic variant called apoE4. And finally, cancer. Many cancer cells rely heavily on glucose known as the Warburg effect. So the theory is that ketosis might put them at a metabolic disadvantage, that is, the cancer cells. A 2025 meta-analysis pulled multiple trials of cancer patients and found that a ketogenic diet significantly reduced fat mass, visceral fat, insulin, blood glucose, fatigue, and insomnia while improving cholesterol markers, thyroid markers, and emotional well-being. The effect on actual tumor progression was inconsistent. So this is still something you would need to have your oncology team monitor. Now let's talk about the potential downsides of the ketogenic diet because no diet is perfect. The most common side effect is known as the keto flu. In the first one to two weeks as your body switches from burning glucose to burning fat, you might get headaches, fatigue, brain fog, irritability, nausea, and muscle cramps. This comes mostly from rapid fluid and electrolyte loss as insulin levels drop. So it's important to drink enough fluids and get enough electrolytes because these get depleted so quickly. Other things to watch out for on this diet, constipation since you're cutting out a lot of fiber sources. Some people also see their LDL cholesterol levels rise. This can be monitored. Kidney stones could be a concern, especially in kids using this diet for epilepsy, and in rare cases, especially with certain underlying conditions, there's a risk of diabetic ketoacidosis, which is different from the nutritional ketosis we're talking about for the average person. And because you're cutting out whole food groups, micronutrient deficiencies are also a real risk if you're not careful. This diet may not be appropriate if you have pancreatitis, advanced liver disease, or you have certain genetic fat metabolism disorder. So, check with your integrative doctor on this. And here's one thing that doesn't get addressed enough, and that's your gallbladder. Because this diet is so high in fat, your gallbladder has to release more bile to digest it. And combined with rapid early weight loss, this can increase your risk of gallstones or trigger symptoms if you're already having gallstones. So, you have to be aware of upper right abdominal pain, nausea, digested discomfort. So, if you have a history of gallstones, then this is something you need to talk to your integrative doctor about before starting. What about the nutrients that you may need to supplement? Cuz this is so important that we don't want to end up with nutritional deficiencies, which causes a bunch of symptoms. I talked about electrolytes, sodium, potassium, and especially magnesium. They get flushed out fast in early ketosis, and low magnesium can cause cramps, poor sleep, and fatigue. Many doctors like myself recommend 300 to 500 mg of mag- nesium glycinate daily, plus enough sodium potassium-rich foods like avocado and leafy greens to bump up these minerals. Second, vitamin D. Most people are are low in vitamin D already, so it's worth checking your levels. Most of my patients need between 2,000 to 5,000 units daily. Also, omega-3 fatty acids like EPA and DHA. If you're not eating enough fatty fish regularly, especially on this diet, then you may want to supplement omega-3s to keep your omega-6 to omega-3 ratio balanced. Also, B vitamins, especially vitamin B1, thiamine. Uh, it's important for energy metabolism, and it can get low on a low-carb restricted diet. A B complex is really the best way to replace your B's. Then, fiber. Something like psyllium husks can help, since you're cutting out a lot of foods that normally help keep things moving, and you need more fiber. Also, consider calcium, especially if you're limiting dairy in your keto diet, even though you can have it. Around 500 to 1,000 mg a day might be needed depending on how your diet is. So, that's the ketogenic diet in a nutshell. What it is, what to eat, what to avoid, what it's been studied for, the side effects to watch for, and the nutrients you might want to supplement. It's a powerful dietary tool, but not a one-size-fits-all. So, always recommend working with a healthcare provider trained in nutrition, especially if you have chronic health conditions and you're going to make big changes in your diet. Well, if you found this helpful, give it a thumbs up. Subscribe if you haven't already, and drop any questions you have down in the comments. I'm going to really focus on reading and answering each one of them. Thanks so much for watching, and I'll see you in the next video.
MEDICAL DISCLAIMER: This video is for general information and educational purposes only and does not constitute the practice of medicine, the giving of medical advice, or the establishment of a doctor-patient relationship. The information provided is NOT intended to be a substitute for professional medical advice, diagnosis, or treatment, and is NOT intended to treat, diagnose, cure, or prevent any disease or medical condition. Always seek the guidance of your physician or qualified healthcare provider with any questions you may have regarding a medical condition. Do not delay or disregard seeking professional medical advice based on anything contained in this video. Do not make any changes to your health regimen, medications, or supplements without first consulting your physician or healthcare provider. Dr. Mark Stengler assumes no liability for any direct or indirect losses, damages, or adverse outcomes that may result from use of the information in this video. All content is provided for educational purposes only and is subject to change without notice.