”If you look at, for example, some of these high fat high protein diets , in the beginning everybody thought they were a great idea because people lost weight, and then it turns out, as the epidemiological studies started coming out, they are some of the worst diets you can have, and they promote higher mortality, and higher incidents of all kinds of diseases…and sure enough, there are no very long lived populations that have a high animal fat, high animal protein diet.” Dr. Valter Longo
Diets come and go. They often have catchy names like Keto, Paleo, Whole 30, Atkins, South Beach, etc. Today, the Ketogenic Diet is where everyone is playing, particularly for those ether seeking rapid weight loss and/or perceived gains in athletic performance. Upon hearing what people say can be eaten on a Ketogenic diet, the thought is of perhaps a slightly more extreme Atkins or a modified Atkins depending on what advice is being followed. In reality, the Ketogenic Diet was tested and developed decades ago to specifically treat non-drug responding epilepsy. To date, epileptic patients, mostly children, and possibly some other medically determined groups are the only people who should be following a supervised ketogenic diet. Clinicians say that getting adult patients to live on a supervised ketogenic diet is nearly impossible due to side effects and very limited foods (i.e: boring).
Unfortunately, the eating plan that the majority think (or hope) represents a ketogenic diet is the elimination of carbs (good carbs and bad carbs – there is a HUGE difference, but not for Keto) and the addition of much fat and protein. In reality, a ketogenic diet was developed to be 90% fat and the remaining 10% protein and carbohydrate. Keto is a high fat, low protein, extremely low carb diet NOT a high fat, high protein diet. So if you are eating a lot of meats, eggs, dairy, and seafood along with some veggies and all that butter and oil, you are not following a ketogenic diet and will not only not get into ketosis but begin doing some damage to your body and health. VERY few people can truly get into ketosis or stay there – nor should this be a goal for most people.
So what is the objective of a ketogenic diet for the non-epileptic person? To try to get the body to stop using glucose for fuel and start burning fat. Our bodies and brains run on glucose as fuel of choice. Yes, our brains need fuel. Glucose comes naturally from many foods, mostly from the plant world – fruit, vegetables, whole grains, and legumes. The body then converts the glucose to glycogen to use as muscle and brain fuel. An athlete will ‘bonk’ if they run out of glycogen before replacing it. We have about 2 hours of physical exertion worth of glycogen stored. This is why endurance athletes use simple carbohydrates during long events – to quickly replenish and keep performing. One or two well-known ultra-runners have dabbled in ketogenic diets but not long-term and not during events, oddly enough, as they know that when their fuel source is drained – be it fat or glycogen – they are not going to be eating fat during the race (think digestion and processing in the gut!).
Now if the brain doesn’t have any glucose left, how will it function? When the body goes into starvation mode it begins to use its own muscle tissue to form glucose. This, of course, is not what anyone wants. In a true ketogenic diet, by keeping just enough protein and carbs in the system (10% of daily caloric intake), the goal is for the body to then create ketones from body fat to feed the brain and fuel activity. This is the simplistic explanation. While some very dedicated people may get close to ketosis, or be in ketosis for a short period of time, most do not.
The short term effects, aside from early weight loss (which has been shown to be predominantly water and common to all restricted diets) are bad breath, an odour in the urine, constipation that never goes away, brain fog and low energy. Sounds awesome! If true ketosis is maintained, the energy levels and brain fog are said to clear but not the odours or constipation, which may account for some loss of appetite. While some may think this is all OK, what about impact on long-term health? Is this way of eating life-giving?
First question is to ask why do a ketogenic diet? Chance are it is to lose weight and results can happen fast while being able to eat lots of meat and dairy (hence the popularity of Atkins) or you may be an endurance athlete thinking that you could do an ultra on nothing but water and your stored body fat and not have to choke down gels. But are you also looking to shorten your life and possibly damage your organs, kill off your microbiome (your good gut bacteria) and bring on Type 2 Diabetes or a heart attack or some cancers? That is what eating this way may ultimately do for you. Longevity studies only show that communities eating high complex carbohydrate diets live longest in health. There are always outliers, of course, but we are looking at larger populations.
What does eating 90% of calories from fat look like? Lots of butter. Lots of coconut oil. Lots of meat and dairy. Little variety. All have no fibre (the only food of the microbiome and the means to keep your system moving). All are loaded with saturated fat. Thus dedicated keto dieters experience constipation, loss of appetite, likely long-term damage kidneys and liver, clogging of arteries (raised LDL and triglycerides) causing your body to degenerate and/or develop disease(s) much faster. Dr. Longo’s quote above says high fat/high protein, which is how most people interpret ketogenic eating but in conversations and his research papers he also states that the ketogenic diet could shorten lives by an average of 5 years.
There are a lot of sites and studies that support use of keto to lose weight yet to date there are no long-term studies (and only a handful that go out one year) on the effect to the body on a long-term dedication to such a restrictive diet. At one year, it does not come out ahead of high carb/low fat or plant based. Keto – true keto – is almost impossible to do outside a clinical setting. It is very limited in foods and virtually impossible to dine out of the house. If you are not struggling to do this diet day in, day out and not continuously measuring your ketone levels to see where you are at, you are not on a ketogenic diet. You are on Atkins or just eating what you want to eat (fatty foods) and not what you don’t (plants). If you are still keen to be high fat, switch from animal fats to plant fats (avocado, nuts and seeds) to see improvement in health outcomes. That would be my only suggestion to try to reduce the inflammation, disease and aging results of an animal based keto diet. There are some sites out there that can direct you to a vegan keto-like diet. I do not recommend this to my clients.
If you are interested in short-term experimentation (5 days), doing some sort of fasting (which is effectively a form of ketogenic diet) or following a plant-based keto diet for that short time could help eliminate some water weight and lean out for an event. Just be mindful of your choices and the impact on your gut and long-term health. Periodic or supervised fasting itself has many benefits but that’s another topic!
The take-away is cliche – if it sounds too good to be true it probably is. Let your common sense take over. Eating 90% of your calories in saturated fat…hmmmmm.
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