There’s also some evidence that it might help with type 2 diabetes. “An emerging body of research is finding that a keto plan may have some real benefits thanks to its ability to improve the body’s ability to use insulin and also help control appetite, which can result in easier weight loss,” says Karen Ansel, R.D.N., co-author of Healthy in a Hurry.
Fascinating stuff and I am quite curious how we know for certain one is actually in ketosis i.e. using ketones as primary fuel source BECAUSE we do know that glucose has a shorter metabolic pathway to burn and under most conditions, given the presence of glucose, that is what the body will default to which is why high fat and high sugar together in diet is so detrimental. So if we use one or more of the above “boosters” and show high levels of blood ketones but also highish levels of glucose (during initial transition) will be mostly burning ketones or still defaulting to glucose?

I just discovered your site and have been thoroughly enjoying many of the articles and appreciate that you get so in depth in your explanations. I’m in my late 40’s and, while not an extreme endurance athlete, I am moderately active with 18-20 mile rides 3x a week as well as some boxing and body weight resistance (push up, pull up, etc) mixed in. I’ve generally been paleo and stick to quality macros for the most part (grass fed meats/dairy, organic veg and oils) and zero supplements. I recently started following keto (after reading this article) about 10 days ago and things seem good thus far. I do, however, want to avoid any of the negative side effects you mention and also not lose any lean muscle. I’m currently about 174 lbs, 5’8″ and about 19% bodyfat – I’m taking in about 95g protein, 130g fat and <20g net carbs. I'm eating all quality – wild salmon, grass fed beef, pastured eggs, coconut oil, Brain Octane and Grass fed butter in coffee, sardines, etc. With a smattering of organic veg, but it seems real easy to bust through the carb barrier. *I'M ALSO TAKING KETOCANA PRE-WORKOUT* and I notice this is keeping me going throughout a ride or the gym.

-Cancer: Numerous studies have found that the risk for cancer increases with high blood sugar, which makes sense, since cancer cells feed primarily on glucose. This includes cancers of the endometrium, pancreas, and colon and colorectal tumors. Tim Ferriss recently hosted a fantastic article by Peter Attia about this very issue, and how ketosis may indeed be a potential cancer cure.
“Given that there is no known detriment to consumption of a high-carbohydrate diet (other than body weight gain due to water retention) and some research reports a benefit, it is recommended that all athletes consume a high-carbohydrate training diet, i.e., at least 60-70% of energy as carbohydrate (7-10 g/kg), and increase this to 65-85% for the few days before competition. Use of a carbohydrate supplement before and during exercise will likely improve performance of intermittent, high-intensity sprints.”
Although you'll be cutting way back on carbohydrates and sugar, some fruits are still okay to eat on the keto diet (though you'll still want to be mindful about quantity in order to remain in ketosis). The fruits that make the cut contain far fewer carbs than their off-limits cousins such as apples, pears, bananas, pineapples, papayas, grapes, and fruit juices in general.

On the ketogenic diet, carbohydrates are restricted and so cannot provide for all the metabolic needs of the body. Instead, fatty acids are used as the major source of fuel. These are used through fatty-acid oxidation in the cell's mitochondria (the energy-producing parts of the cell). Humans can convert some amino acids into glucose by a process called gluconeogenesis, but cannot do this by using fatty acids.[57] Since amino acids are needed to make proteins, which are essential for growth and repair of body tissues, these cannot be used only to produce glucose. This could pose a problem for the brain, since it is normally fuelled solely by glucose, and most fatty acids do not cross the blood–brain barrier. However, the liver can use long-chain fatty acids to synthesise the three ketone bodies β-hydroxybutyrate, acetoacetate and acetone. These ketone bodies enter the brain and partially substitute for blood glucose as a source of energy.[56]
The bottom line is that there have not been enough scientific studies, especially longer term ones, to really determine all the potential risks and benefits of the keto diet. Many of the claims out there on the Internet, social media, or television in either direction are anecdotal, meaning that they are individuals telling stories about what has supposedly been their experiences. Take everything you hear that is not supported by scientific evidence with a grain of salt (but not too much salt because too much can be bad for you.) 

The Gatorade Sports Science Institute (GSSI) is widely considered one of the world’s top go-to resources for cutting-edge exercise and nutrition science advice – which is probably why Gatorade vending machines dot the campus here, and the majority of the kids seem to be walking around campus with a never-ending big gulp-sized cup full of sports drink.
I’m brand new to the Keto scene. Just started the diet on tuesday. There are so many supplements listed here. Is there a place to start? Like only starting with a couple? What about blood testing, do you recommend it it and how often and should i even be testing in the first month. Any help is greatly appreciated. You have the most informative articles I’ve been able to find.
Lots of apps and websites offer keto diet challenges—basically, a blueprint for the keto diet with a fixed starting and ending point (they typically last for a week to a month, though some may be longer). Speaking of apps, plenty of keto-centric ones are right at your fingertips (a.k.a., your smartphone), like the KetoDiet app, which can help you calculate your macros and track your keto diet effectively.
Keep in mind that if your crotch begins to have a very unusual smell, whether or not you are on the keto diet, you may want to see your doctor. Don't just tell everyone on Reddit about how much your crotch smells. Regardless of your gender, an unusual smell could be a sign of an infection or some other condition that needs proper medical attention. Even if you don't have a medical problem, your doctor can tell you what kinds of smells are normal and not normal. In other words, he or she could lower your concerns about what's going on in the lower part of your body.
What is the link between ketones and diabetes? Ketone is a chemical produced by the body when fats are broken down for energy. Ketone testing is important for people with diabetes, because high levels can lead to diabetic ketoacidosis (DKA), when acid levels become too high in the blood and the person loses consciousness. Find out when and why to do ketone testing. Read now

To understand exogenous ketones, you should know that there are three types of ketones: beta-hydroxybutyrate (BHB), acetoacetate (ACA) and acetone, and all three are the normal by-products of fat breakdown by your body. In much the same way as glucose, ketones can be used by your tissues, especially your brain, diaphragm and heart and are actually a far more efficient fuel source than glucose.
Our bodies are incredibly adaptive to what you put into it – when you overload it with fats and take away carbohydrates, it will begin to burn ketones as the primary energy source. Optimal ketone levels offer many health, weight loss, physical and mental performance benefits.1There are scientifically-backed studies that show the advantage of a low-carb, ketogenic diet over a low-fat diet. One meta-analysis of low-carbohydrate diets showed a large advantage in weight loss. The New England Journal of Medicine study resulted in almost double the weight loss in a long-term study on ketone inducing diets.
Amazing article – gonna have to print it and read it again. To much to break down in one sitting. Thanks Ben – you’ve pulled together so much insight and references that’s given me greater confidence and conviction. I’m 50 and use to be super active and a seasoned athlete but after a few ‘mid life surgical interventions’ I had to find a better way… Ketogenics has been that for me… no more inflammation… I can’t tell you how great it’s been to be pain free! Keep leading from the front.

Carbohydrates have been linked to this skin condition, so cutting down on them may help. And the drop in insulin that a ketogenic diet can trigger may also help stop acne breakouts. (Insulin can cause your body to make other hormones that bring on outbreaks.) Still, more research is needed to determine exactly how much effect, if any, the diet actually has on acne. 
I’ve been experimenting with MCT Oil Brain Octane. I have one questions. I’ve been eating about 20 – 25 gr. of carbs per day on a high fat, medium protein diet. I’m measuring ketones in the morning before taking the MCT and after. I’ve been taking btw. 1-2 tbsp of MCT Brain Octane with butter (Bulletproof coffee) – I measure again after 30 min., 1hr, 2 hrs. and don’t see a raise in my blood ketones. Anything I’m missing, would love to hear your thoughts, Ben. – Thx I’m measuring with Precision Xtra and Ketonix Red.
I talk about that quite a bit here :https://bengreenfieldfitness.com/2015/09/things-your-pee-can-tell-you-about-your-body/
When glucose levels are low, especially over time, most cells will switch to using ketone bodies for fuel. Ketones allow cells to be metabolically flexible, so to speak. Even the brain and nerve cells, which are heavily dependent on glucose can utilize ketone bodies for fuel. This ability of most normal cells to use ketones when glucose is unavailable indicates that their cellular mitochondria are healthy and functioning properly. 
Thank you for this article as it cleared up a bunch of stuff for me. I started trying to get into ketosis back in August and lost 20lbs in about 6 weeks. Then it all stopped but had another 20lbs I wanted to loose. I had a hard time staying in ketosis and gave up about a week ago with the holidays approaching. Anyways I glazed over all the technical and science facts as it makes my head spin and might of missed it but my only question is what is the food portion of the diet like? The drinks are the easy part, do you have a diet plan that is good for someone that hits the gym hard 4-5 days a week for and hour and half. 45 min weights and 30-45 min cardio? It’s what I struggle with most the food and what attracted me to a ketogenic diet in the first place is eating 1 or 2 meals a day and being satisfied.

In addition to adding in precious electrolytes such as potassium, magnesium, sodium, chloride, and calcium for supporting nerve impulses and muscle contraction, the Gaspari Nutrition R&D Team have also build their Osm Technology into this product. This “new way” of looking at carbohydrate drinks utilizes a proprietary method of tuning the electrolytes in solution with pure cyclic dextrin to get an optimal osmolality (mOsm). In a nutshell, this results in lower osmolality, and lower osmolality results in faster gastric clearance, and a clean, easy burn of your fuel.


Hi Ben – Great article. I had trouble at the end figuring out if you were now eating high fat (60-80% of calories), or if you went back to something closer to 50% fat calories and higher carbs and are using exogenous ketones to get int ketosis when needed. Are you doing any carbs at night or a refeed, or just having higher carbs on most days? Thanks
And it all culminated with me stepping into Dr. Jeff Volek’s world famous laboratory at University of Connecitut to subject myself to extensive blood testing, chunks of muscle removed from my legs, fat sucked out of my butt-cheeks, urine, stool and gut microbiome testing, oxygen and carbon dioxide testing and countless hours of treadmill running to discover what a full twelve months of eating a ketotic diet had actually done to my body.
You also get incredible gains in metabolic efficiency when you use fat as a primary source of fuel – especially when doing high-intensity interval training – with this one-two combo causing potent 3–5 percent decreases in the oxygen cost of exercise, which is extremely significant. Translated into real- world numbers, this increased fat utilization from carbohydrate restriction and high-intensity interval training would allow you to pedal a bicycle at a threshold of 315 watts, whereas a high-carbohydrate, aerobic-only program (the way most people train) would allow for only 300 watts. Talk to any cyclist and you’ll find out that an 15 extra watts of power is huge in a sport like cycling, and something most cyclists train years and years to achieve.
Keto, or Ketogenic diets, limit the amount of carbohydrates you eat and increase the amount of fat you eat in order to get your metabolism into a state of Ketosis. In Ketosis, your body burns fat for fuel instead of carbohydrates (it’s preferred fuel). The Ketogenic diet is known as a way to lose weight because as you provide less carbohydrates, your body will burn the fat you eat and have stored as fuel. But Ketogenic diets are also known for their multiple health benefits. To read more, check out our blog post on Ketogenic diets here.
Ketone bodies are acidic, but acid-base homeostasis in the blood is normally maintained through bicarbonate buffering, respiratory compensation to vary the amount of CO2 in the bloodstream, hydrogen ion absorption by tissue proteins and bone, and renal compensation through increased excretion of dihydrogen phosphate and ammonium ions.[9] Prolonged excess of ketone bodies can overwhelm normal compensatory mechanisms, defined as acidosis if blood pH falls below 7.35.

I've tried that before(enzymedica digest gold for example) but it didn't seem to help much. It seems from testing that I have some heavy metal stuff going on and there might have been a chronic mold exposure in the past that is still reeking havoc and I imagine that might be affecting this pretty heavily. I will definitely be sticking to the avocadoes and coconut and 100% dark chocolate because I can't tolerate dairy. The hard part is figuring out what is the bare minimum of starch to make my gut feel good and be regular and at the same time become fat adapted and get those increased cognition and longevity benefits!!
Long-term disruption of menstruation can bring on serious side effects, including low bone density. “This is because estrogen is very important to bone health,” says Yawitz. “Studies have also found prolonged menstrual irregularity to increase risk for cardiovascular disease, depression, anxiety, and sexual dysfunction. It’s important to contact your ob-gyn if your cycles become irregular or if you stop having periods.” 

To encourage ketone production, the amount of insulin in your bloodstream must be low. The lower your insulin, the higher your ketone production. And when you have a well-controlled, sufficiently large amount of ketones in your blood, it’s basically proof that your insulin is very low – and therefore, that you’re enjoying the maximum effect of your low-carbohydrate diet. That’s what’s called optimal ketosis.
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