Ketones are also a cleaner-burning fuel than carbs. They’re burned for energy in the mitochondria, and fewer free radicals (a highly-reactive, short-lived uncharged molecule) are generated when compared to burning glucose.15 What’s more, ketone molecules themselves cause a decrease in production of free radicals,21,22 while also increasing glutathione–a powerful antioxidant protecting against mitochondrial damage induced by free radicals.23
Because some fruits have more carbs than others, knowing which to avoid is key for accelerating weight loss and reaping other possible benefits of keto. Just know that large, long-term, randomized controlled trials on the keto diet are limited, so it’s unclear whether keto is safe and effective to follow for the long haul, according to Harvard Medical School.
A small Feb. 20, 2017, study looked at the impact of a six-week ketogenic diet on physical fitness and body composition in 42 healthy adults. The study, published in the journal Nutrition & Metabolism, found a mildly negative impact on physical performance in terms of endurance capacity, peak power and faster exhaustion. Overall, researchers concluded, “Our findings lead us to assume that a [ketogenic diet] does not impact physical fitness in a clinically relevant manner that would impair activities of daily living and aerobic training.” The “significant” weight loss of about 4.4 pounds, on average, did not affect muscle mass or function.
I am trying to get back into keto. I did it before and I was so happy when I lost 10lbs (I did the keto for a month). I am ready to go back to this lifestyle. All this information is very helpful, I have written it all down so it can be easier for me to remember what is allowed and what is not. Looking forward to get back on this keto journey. Thank you for all the great info.
“Studies have shown that the ability to stick to a diet is more important for long-term success than the type of diet that’s followed,” says Yawitz. “Keto is incredibly restrictive and is particularly tough for those who have frequent social engagements or are prone to carb cravings.” The Mediterranean diet allows you to eat carbs, like as many fruits and veggies as you want, along with whole grains. Not to mention, the Mediterranean diet has been linked to a number of other health benefits, including a lower risk of Alzheimer’s and Parkinson’s disease, certain types of cancer, and heart disease, according to the Mayo Clinic.
Hello, may I ask if someone has some experience week fasting for 14 days? I was told that the food which should be started taken after 14 days of fasting has to be in very simple and in slow amount. Unfortunately 1-2 days after fasting I am allowed to take only bouillon out of buckwheat, barley, from the 3rd day buckwheat mush, and only from 5th day milk or sour cream, oil since 11th day. Can anyone advice how should I adopt this come back food path to Ketogenic diet? Thank you in advance, Maria
Ben. I do not read epidemiological studies anymore… Just biology. There are plenty of examples of traditional cultures consuming high carb (and high fat) without any of the health issues those studies in your article claim. So either high fat or high carb both work if done properly… AND in the right environment. Both are ancestral not just one of the two and have posit and negat because it has to do with the climate and environment around. I do not listen to anybody that pushes JUST one because they are ignoring the reality. I hope you join this "common sense" wagon.
Exogenous ketosis comes from an external source. Consuming exogenous ketones, like a ketone drink containing a ketone ester or a ketone salt, raises blood ketone levels. The body isn't producing ketones in this state, but still remains in ketosis from having ketones introduced from an outside source. However, the body isn't ketogenic–that specifically means the body is producing its own ketones.
For example, in trained people and athletes who eat a low-carbohydrate, high-fat diet (not to be confused with a low-carbohydrate, high-protein diet), a large amount of fat burning can take place at intensities well above 80 percent maximum oxygen utilization (VO2 max) – allowing for very-high-intensity or long efforts with low calorie intake and also allowing for use of fat fuel stores during long steady-state exercise, even at a relatively fast pace (so much for the “fat burning zone” giving you the best bang for your buck). With high-fat, low-carb intake, you can go hard and still burn tons of fat. In addition, this means that more carbohydrate stores will be available when you really need them, such as for an all-out, 100%, maximum effort.
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]
Checking your ketone level is one way to know if you’re in ketosis. This metabolic state usually kicks in after three or four days of restricting your carbohydrate intake or going through periods of intermittent fasting. You don’t have to visit a doctor to measure your level. Pick up a ketone urine test from a nearby drug store, or use a blood sugar meter that’s capable of measuring ketones.
Hi Gigi, Low carb and keto is about the balance of macronutrients eaten (fat, protein and carbs), not specifically meat or lack thereof. Most people on keto do eat meat, though some people do vegetarian keto. Fat is actually necessary for many body processes. There is no issue for the kidneys with a high fat diet, but if you eat too much protein that isn’t great for the kidneys. It’s a common misconception that keto is high protein (it isn’t). Keto is great for diabetics as it naturally helps stabilize insulin. All of this being said, please know I’m not a doctor and you should consult your doctor on any medical questions or before starting any diet. If you have more questions that aren’t medical questions, I recommend our low carb & keto support group here.
The longer cholesterol circulates in your bloodstream, the higher the likelihood that it will dig its way into an endothelial wall and potentially contribute to atherosclerosis or plaque formation. This is why it’s so dangerous to eat a high-fat diet, but to also have your nightly dark chocolate bar, overdo it on the red wine, or have weekly “cheat days” with pizza, pasta, or sugar-laden ice cream.
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.
In other words, I personally found that while following “strict ketosis”, things became eerily similar to the days in college when I was a competitive bodybuilder pursuing sub-3% body fat percentages. I simply wasn’t the most fun guy to hang out with in social situations due to my extreme dietary restrictions, the intense self-control became nearly exhausting, and when I traveled, I missed out on many culinary experiences, such as homemade ravioli in Rome, freshly baked crostinis in the Basque regions of Spain, and Korean rice bowls in Seoul.
If you prefer a more direct, customized approach, I'd be happy to help you via a personal one-on-one consult. Just go to https://bengreenfieldfitness.com/coaching. and then choose a 20 or 60-minute consult, whichever you'd prefer. I can schedule ASAP after you get that. Additionally, if I'm "out of your price range" (yes, yes, I know I can be a spendy guy to access) I have a team of coaches I've personally trained who can help you here: https://greenfieldfitnesssystems.com/product-cate…
That was really interesting and useful information. But I wanted to ask you about what Dom said at time (52min). What does he mean,when he says 1 mml increase is about 10% increase of substrate to the brain? Is that (same glucose amount in brain) + (typical ketone amount in brain)+ and 10% more? Or does it substitute glucose? And if it is so, does the brain use that energy or does it just stay around the brain without being used? I know we can’t know for sure, but it would be helpful if you said what you think. Thanks in advance!

Protein will induce an insulin response in the body, if consumed in high amounts. The most intuitive way to start a keto diet for most people is by removing all of the carbs they have been eating. Typically people will replace those calories by increasing their lean meat consumption. That's a recipe for disaster! Keeping protein moderate is an often overlooked, but very important part of a keto diet. Most people need around 0.6g to 1.0g of protein per pound of lean body mass.
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