The Keto Diet (or ketogenic dieting) is a way of eating that is based on a high fat intake and a low carbohydrate intake. Reducing carbs puts your body into ketosis. There are various advantages and disadvantages – this article covers them all!
The whole world it seems is banging on about the Keto Diet
There is so much Keto Hype and utter BS I want to scream.
I have written this article to separate the fact from fiction.
It is very long and covers everything you need to know on the subject.
I am not adverse to the principle or the theory – I am opposed though, to the total nonsense that is spouted by people who don’t understand the process or do and should know better.
Did you know that in ketosis you are actually burning pure fat and have 5 times more energy, so you can get lean and strong much quicker than everyone else?
Did you also know that by following a ketogenic diet, you trigger your “immortality” genes and basically live way longer than people who eat carbs?
The above statements are examples of the hype and zealotry that have arisen from the recent wave of low-carb-high-fat keto diet popularity.
I say ‘recent’ because ketogenic diets and low-carb-high-fat (LCHF) diets are nothing new, despite what many people now ardently following them think.
Ketone bodies, ketogenesis and ketosis are all parts of a cyclical system that our bodies use in certain circumstances – like when the liver is processing an abundance of fat and very low carbohydrate quantities.
There are some pretty woeful keto themed diet pill currently on the market we would suggest giving some of these a very wide berth. here are a few:
- Purefit Keto: We have a long comments thread on the bottom of this review written by customers that were less than pleased with their purchase.
- Flawless Keto: Very similar to the product above. Anything but flawless we would say.
- Purelife Keto: Ditto
People have been inducing dietary ketosis – either through choice or lack of it – for so long that the timescale is practically irrelevant. Put it this way, the keto diet is not a post-millennial invention.
For anybody that’s heard bits and pieces about keto but doesn’t really understand it, or those who want a completely unbiased opinion about the pros and cons of following a ketogenic diet, then this article is offering to you.
You may have heard ketogenic dieters vilifying high protein consumption because they believe it can “kick you out of ketosis”.
Or perhaps you’ve read how keto fixes insulin resistance and turns it into a super hormone.
Whatever you’ve read, or heard, or been told about the ketogenic diet, I think what you read in the following paragraphs will be a worthy addition to your knowledge of the subject in any case.
What is Ketogenic Dieting?
There are countless explanations of the keto diet on the internet, so basically I’m about to lob another one on to the pile.
I have noticed, however, that many of these explanations are either from keto advocates, or pro-keto websites.
When it’s not coming from #teamketo, it’s often coming from scientists, and they very rarely resist the urge to whip out the vernacular and start drawing venn diagrams and flow charts containing all manner of shiny abbreviations that are nonetheless meaningless to the vast majority of humanity.
So, I find simple and neutral works best.
Ketogenic dieting is when the major proportion of your daily calorie consumption comes from fat.
About 5% or less of a keto dieters calories come from carbohydrates. In fact, to be considered a true, card carrying, keto club member you would eat less than 50 grams of carbohydrate a day.
The rest of the calories are protein of course.
A typical ketogenic dietary macro split might look like this:
- 75% calories from FAT
- 20% calories from PROTEIN
- 5% calories from CARBOHYDRATE
When you consume less than 50 grams of carbs per day, your liver is forced to manufacture ketones, or ketone bodies, from fat so that it can (a) store its meagre offering of carbohydrates in the form of glycogen, and (b) deal with the high volume of fat passing through it.
The liver itself cannot use ketones for energy because it lacks an enzyme that converts them into the correct form. Hence why it hoards its glycogen.
So, as levels of carbs get really low, the liver converts fatty acids into ketones. Ketones can travel to many parts of the body, including the brain, and be used as a source of energy.
When ketones are being produced by the liver, the process is known as ketogenesis. This actually happens for everybody to a certain degree, not just keto dieters.
If levels of carbs are low enough that the liver is forced to do this in order to supply energy, the body is said to be in ketosis.
Ketosis is a normal metabolic process that can occur as a result of intense or endurance exercise, fasting and involuntary starvation. Basically any situation when carbohydrate intake is low enough and fat becomes the main source of fuel.
What we are discussing here is diet-induced ketosis, or nutritional ketosis, where the macronutrients are apportioned in such a way as to force the body into this state.
What Are Ketones?
Ketones can be called ketone bodies, and they are chemicals that are produced by the liver when it processes excess fatty acids.
In a way their production can be seen as a marker for a high fat to low carb ratio.
The 3 ketone bodies are:
These ketones/ketone bodies are made from acetyl-CoA (aka acetyl Co-enzyme A), which is a basic carbon-bearing fuel which enters the citric acid cycle (aka Krebs cycle) to be used as energy by any mitochondrial cell.
The citric acid cycle takes place within the mitochondrial matrix of cells. The mitochondria are like little power stations, and their matrix can be considered to be within the confines of their own little membrane.
Those 3 ketone bodies are water soluble and can be transported by blood around the body.
They can cross the blood-brain-barrier and enter through cell membranes.
Once inside the cell, they can be converted back to acetyl-CoA, which can donate its acetyl group to the citric acid cycle to yield energy.
This is important because fatty acids themselves cannot cross the blood-brain-barrier (BBB) so ketones are extremely important for central nervous system (CNS) function in the absence of glucose.
The brain does still require a certain amount of glucose to operate, as does the liver, kidneys and blood. If this is not supplied in the form of carbohydrates, or in times between carbohydrate consumption, then the process of gluconeogenesis (the generation of glucose from non-carb sources) is employed.
Gluconeogenesis is discussed in more detail in the Protein and Keto section below.
Which Organs and Tissues Can’t Use Ketones?
There are several cells in your body that cannot use ketones / ketone bodies:
- Renal medulla (inner part of kidneys)
- Red Blood Cells
- Parts of the Brain
These rather important body parts, not to mention red blood cells, still rely on glucose. For example, the liver doesn’t have enough of the transferase enzyme which converts the ketones to their energy-yielding form and red blood cells don’t have mitochondria.
Ketogenic dieters needn’t worry though, our bodies undergo a process called gluconeogenesis: the generation of glucose from specific non-carbohydrate sources.
Gluconeogenesis is a highly regulated, accurate process, whereby the necessary quantity of glucose for the maintenance of blood sugar, brain function and liver function is generated.
One of those sources is protein, and that brings be to the subject of protein consumption in the context of a ketogenic diet.
Protein and Keto
I’ll begin this section by highlighting a fear that many ketogenic diet worshippers have.
If I consume too much protein, won’t its conversion to glucose kick me out of ketosis?
The short answer is: no.
Let’s elaborate on the perceived problem. When you’re in ketosis, you’re using fat as your main source of energy.
Carbohydrate intake can definitely interrupt ketosis, that much is obvious, but since the body prioritizes glucose/glycogen as an energy source, surely it will start converting those substrates that it can into sugar via gluconeogenesis.
Furthermore, excess protein (in order to prevent muscle wastage) might be used as that substrate.
To reiterate: the above fear is unfounded.
Scientifically speaking, the process of gluconeogenesis is not driven by the supply of excess substrate – i.e. protein and glycerol (from lipids e.g. triglycerides) – it is driven by demand.
In other words, excess protein won’t be converted into glucose unless it’s needed for the liver, kidneys, blood or brain.
Studies have shown that this remains the case regardless of any additional consumption of protein. [source]
Gluconeogenesis is a system that constantly strives to maintain a perfect blood sugar concentration, and it doesn’t care whether you are in ketosis or not. A well regulated blood sugar concentration is a must for everybody.
Due to liver glycogen and blood sugar being rather short term stores, and easily depleted, gluconeogenesis is extremely important for restoring them and preventing the negative physiological responses that occur as a result of severely low glucose levels.
One of the reasons for this is the low rate by which gluconeogenesis occurs. Unlike carbohydrates, the conversion of protein and glycerol to glucose are a slow process.
The concomitant glucose production certainly cannot have the same impact on blood sugar levels as can carbohydrate ingestion. And beyond that which is needed for this and other purposes, such as muscle growth, extra protein does not appear to result in extra glucose production.
An interesting response to the gluconeogenesis fear is one that pertains to glycerol.
Given that glycerol is part of triglycerides, which are lipid molecules that form the main constituent of body fat, it is available to be converted to glucose by the liver. Yet despite its abundance, a person in ketosis will not start generating excess glucose from fat deposits.
Protein, particularly whey protein supplements and certain amino acids like leucine, causes ain insulin response. This can be another source of confusion for avid keto dieters and those who are testing the keto waters alike.
The blame for this mostly lies at the feet of popular online keto advocates who – usually due to financial motivations – purvey a mixture of fact, pseudo-science and utter quackery to increase their base of followers and their bottom line.
Insulin is often the subject, or focus, of the ketogenic proponent’s debate. The stronger opinions amongst #teamketo appear to agree that keeping insulin levels down is one of the primary objectives of the diet.
One can’t really discuss keto without at least touching on insulin and even offering something of an argument to the debate.
Insulin and Keto
As with most things biochemical, context matters.
For keto-pushers, context is irrelevant, because it doesn’t fit their agenda of making the keto diet a cult.
Insulin is required for the metabolism and storage of all three macronutrients: protein, carbohydrates and fat.
When you eat, insulin is released and directs your body’s cells to store the nutrients as required.
Some keto-pushers refer to insulin as a fat storage hormone. Basically, if you eat sugar then insulin stores it in fat cells, and that makes us fat.
The problem with this stupidly simplified muppet-science is that they are discussing insulin way out of context, and unfortunately the current epidemic of obesity – and people’s desperation to lose weight – only serves to bolster their stance.
Mitigate the excess sugar intake
People that overeat become obese over time. Excess food gets stored, that’s just the way it is.
Now, because carbohydrates, and especially those carbs closer to its simplest form – glucose – are digested the quickest and raise blood sugar quickly, insulin’s response to this food source is equally fast.
So when blood sugar is raised, or “spikes”, as a result of fast carbohydrate consumption, insulin is released and tries to store as much of it as possible in order to maintain a steady blood sugar level.
If there is nowhere other than fat cells to store the extra glucose, that’s where insulin is going to store it.
Should this happen frequently enough and on a chronic basis, without any exercise to mitigate the excess sugar intake (I’ll get to that), insulin can become desensitized and simply rush out and store the sugar in fat.
In fact, it can do this so quickly and without care that it removes more sugar from the blood than it should. This causes what has become known as the “sugar crash” where there isn’t enough sugar in the blood for the brain to work properly, and so fatigue sets in.
Once fatigue sets in and blood sugar is low, it can lead to more food cravings to correct the blood sugar. And so the cycle continues, because the more it happens the more it damages insulin’s response.
This problem is known as insulin resistance. Basically, the insulin response has become so poor that it has no beneficial effect anymore.
Insulin resistance can lead to Type II Diabetes eventually.
BUT insulin is not the root cause of this problem. Overeating is.
Think of it like this: when insulin has nowhere left to store glucose but in fat cells, that’s what it must do.
The reason it has been given no choice is because the body’s energy requirements have been saturated by the consumption of too many calories, too often.
Insulin is essentially an anabolic hormone. It adds energy to cells, and because stored energy = mass, the result is cell growth.
When it stores amino acids, the result is more muscle protein, which means larger muscles. The same can be said for the storage and conversion of glucose to glycogen. Muscle glycogen is a fuel store for the muscles. Use your muscles enough and they need this fuel to perform optimally.
Muscle tissue will also grow as a result of the training stimulus and dietary protein and so will need more fuel to power the larger mass.
Insulin is a hero for anyone that exercises, especially bodybuilders.
But back to the problem at hand.
Your bodyweight relies on a balance of energy in versus energy out. When you consume more calories than you burn per day, the extra energy gets stored.
If you don’t exercise much then your muscles won’t need to store any, so it inevitably gets stored in adipose – fat – tissue. Insulin is the major driver of that, hence why it is often vilified.
Eat less total calories than you burn per day and the insulin problem goes away because there is no extra energy to store. In fact, your body must call on the energy it has stored and use it to power its metabolic processes. This involves catabolic hormones which break down stored fat and glycogen to be used as fuel. Weight loss is the end result of this breakdown and burning of fuel.
When insulin does its job properly it is said to be sensitive. Proper insulin sensitivity is what everyone should strive for.
You can repair insulin resistance and increase its sensitivity by doing a couple things:
- Eat a calorie deficit while making sure you get adequate protein for your bodyweight
- Exercise regularly
A mix of resistance training and cardio-vascular exercise works wonders because it re-sensitizes insulin that much quicker. Post-exercise your insulin is much more adept at storing the macro-nutrients in the right places. Muscle tissue, for example, is very receptive to protein and glucose uptake during the first couple of hours that follow a workout.
Exercise also primes your muscles to the need for added glycogen storage. Fast carbohydrates following an intense workout, combined with protein, is one of the best things to consume for recovery and muscle growth. Sadly, many ketogenic dieters still forego this practice because of their preconceived notion that carbohydrates are inherently bad for them.
Training also allows you to be in a hypercaloric condition (calorie surplus) and not damage your insulin sensitivity. Yes, you will put weight on, and yes some of it will be fat, but provided you have not harmed your insulin health, that weight gain – even the fat – is useful. We would not be able to add lean mass without insulin.
Hopefully, you can see that insulin is not the problem and that eating a high fat low carb, or ketogenic, diet in order to reduce insulin levels is only useful if that diet helps you to sustain a calorie deficit.
Furthermore, fat does not really need insulin to be stored as fat. If you overeat and your main macro is fat, it’s going to be stored as such, whether you have low insulin levels or not.
Carbohydrates don’t even necessarily spike insulin levels
Keto proponents that use the insulin argument are the worst of the worst because they don’t even understand their own subject.
Carbohydrates don’t even necessarily spike insulin levels, it all depends on the type of carbohydrate you are eating. What’s more, with healthy insulin sensitivity, sometimes a spike is a good thing, especially at certain times, such as immediately after a workout.
There’s no need to demonize or deify one of the body’s hormones, because in different contexts it is different things.
Similarly, there’s no need to cut out an entire macronutrient from your diet if you don’t want to.
The Keto diet is just one way to achieve an end result. The same result can happen with carbohydrates included in your diet.
In the first part of this article, we established that eating less than about 50 grams of carbs per day puts you squarely in the hardcore keto group.
Your liver can actually store about 3 times that amount of glycogen though – about 150 grams.
Therefore, eating less than that per day means that you will use up your liver glycogen quite quickly (especially if you exercise) and then switch to fat burning.
This sort of “low-carb” dieting won’t get you into full blown ketosis all of the time, but if you decide to fast for a little bit, cut even further on carbs, or exercise, then you are going to trigger the process more easily.
In fact “low-carb” doesn’t really have defined parameters. You could say that anything below the average carbohydrate consumption, which is about 300 grams/day in the US, is low-carb.
Why Go Keto?
There are several levels of keto mentality, ranging from the pragmatic to the pseudo-religious.
Here they are in ascending order of nut-jobbery:
- Ketogenic dieting helps me adhere to a calorie deficit because fat is more filling and I find it difficult to overeat.
I feel less sluggish on the keto diet and I don’t experience sugar crashes anymore.
- Keto burns more fat than a regular carb-inclusive diet because it doesn’t need to work through glycogen stores first.
- You have lots more energy when you’re in ketosis and you’re always burning fat so you lose weight so much quicker.
- Ketones are a cleaner energy source than carbohydrate, they have a muscle sparing effect, can cure diabetes and prevent cancer.
- Ketogenic dieting triggers your immortality genes and extends your lifespan by years. It’s entirely possible that you will never die.
The only one that makes absolute sense here is the #1 on the list.
Some people find that they can lose weight/body fat more successfully on a ketogenic diet because they feel fuller and can therefore stick to a calorie deficit with greater ease.
So, that’s the answer to the question: Diet adherence is the most solid reason to follow a ketogenic diet.
Number 2 on the list is possible as well in the right circumstances, particularly if the individual is going from an uncontrolled, high-carb diet to a ketogenic one.
Number 3 is partially correct in that ketogenic diets do result in a higher rate of fat burning.
However – and this is a big HOWEVER – of course you’re burning more fat at greater rates in ketosis – because you are eating more fat.
Alert!! Alert!! – if some keto zealot is telling you that you’re only burning fat in ketosis, it shouldn’t be news to you. What they are neglecting to remind you of is that it’s absolutely necessary, because you’re consuming so much more of it.
And there’s nothing simpler for the body than storing fat as fat, just so there’s no misunderstanding. A calorie deficit is still necessary in order to lose weight because any surplus of fat will be stored just as easily as putting a shirt on.
Number 4 is an extension of this and goes a bit further to say you have more energy!
It’s where I have to really draw the line with people. At least Number 3 has some kind of logic, even though they are missing the point by a mile.
The Energy Debate
More energy on keto. This concept comes from people who have interpreted from certain studies and scientific literature that fat can yield more Adenosine Triphosphate (ATP) than glucose.
The real cuckoos go on to say that glucose is an inefficient form of fuel/energy and that the body “prefers” to burn fat because it’s so much more dense with energy.
First off, if our bodies “preferred” to burn fat then surely it would prioritize fat as the primary source of fuel, and not glucose which in fact it does?
Secondly, the fact that fat can yield more ATP when compared unit for unit with carbohydrates doesn’t make it automatically more efficient.
Per given volume of oxygen, glucose yields more ATP than fat.
The oxygen cost of burning fat doesn’t hinder us much when we’re going about daily business, but if we’re glycogen-depleted when we come to do exercise, it can make a whole lot of difference.
Low Carb versus Ketogenic
Considering the hardcore keto-pushers talk about how much energy is flowing through them all the time, you’d think it would translate to higher energy for exercise, and thus greater muscle and fitness gains.
Despite what they say, we’ve known since 1920 [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1263890/] that for a given volume of oxygen, more ATP can be generated from carbohydrate compared to fat.
As exercise intensity increases, oxygen becomes the limiting factor and so our bodies rely more and more on carbohydrate – and therefore glycogen – to get the job done.
Now, we can train our bodies to become more efficient with respect to oxygen utilization by exercising at certain percentages of VO2 Max.
Keto advocates often think this means that we can somehow convert our bodies to perform at maximum potential using fat as the fuel.
In fact what we are doing when we train is adapting our bodies to be more efficient with our use of oxygen.
This means that if you took two endurance athletes – 1 on a ketogenic diet, and 1 on a regular carb-inclusive diet – and trained them, they would both improve their VO2 Max, which is a measure of the capacity for oxygen consumption.
However, the ketogenic athlete would still not be able to perform at the intensity of the carb-inclusive athlete because the latter still has that greater ATP production from glycogen.
Like I said, the issue is pretty much moot in the context of most of everyday life, but competing athletes, or people who want the best results from their training, may want to think long and hard before going full keto.
If you want to delve into an elegant study that demonstrates the limitations of low-carb diets and athletic performance then take a look this one from 2016.
And if you’d rather read a lovely interpretation of that study together with some expert insights from it, then you’d be hard pressed to find a better example than the one by Kamal Patel and the Examine team
That study involved race-walkers, a third of whom followed a keto diet and the other two thirds a regular carbohydrate-inclusive and high carb diet.
Both groups improved their aerobic capacity, and the keto group improved fat-oxidation rates. However, the increased fat oxidation increased oxygen cost, thereby reducing performance at race pace.
No improvement in a 10km test race occurred with the ketogenic group.
Conversely, the moderate-carb and high-carb groups improved their efficiency of oxygen consumption and beat their previous race times by 5.3% and 6.6% respectively.
It stands to reason that the keto group’s fat oxidation rates would increase given their dependancy on fat as their fuel source. As I mentioned before, it is known that more ATP can be generated from carbs per volume of oxygen when compared with fat.
Therefore it also makes sense that with increased fat oxidation comes increased oxygen demand, a limiting factor in exercise performance.
Again, none of this matters until you are approaching maximal output and require your anaerobic engine to contribute some energy.
Compromises – Intermittent Fasting and Keto Windows
Of course, not all keto diet advocates buy into the nonsense that pervades the internet.
While many zealots vilify carbohydrates, the smarter ones understand the importance of glycogen and at least some consumption of carbohydrate is accounted for by them.
With that in mind, there are several options for someone looking to get the benefits of a keto diet, the chief of which is to more easily adhere to a calorie restriction, together with the benefits of carbohydrate feeding for optimal physical performance.
Again they have abbreviations, but it doesn’t really matter what you call them as long as you get the concepts.
Any method which cuts a compromise falls within the general category of intermittent fasting, or IF.
IF is exactly what it sounds like: fasting intermittently. There are many ways and schedules by which to run it by. Some people go a whole day or two without eating and then eat normally for a few days.
Others have feeding windows and fasting windows within a day. It’s all about finding the right fit for you, while keeping in mind that the objective is to encourage an overall calorie deficit.
Athletes and those looking to tinker with their body composition might try methods such as CKD – Cyclical Ketogenic Dieting or TKD – Targeted Ketogenic Dieting.
The cyclical approach – CKD – is more like intermittent fasting but only with carbohydrates. I’ve seen it called Intermittent Carbohydrate Restriction.
The idea of course is to follow a ketogenic diet for a period of time and then “re-feed” with carbohydrates at given junctures.
Nascent research into this sort of practice has highlighted the possibility that flicking the ketosis switch regularly might help certain endurance athletes accelerate their transition into, or improve their efficiency of, fat oxidation.
More research is definitely needed. Also, it would take some getting used to the the process of triggering ketosis and then kicking back out of it with carb ingestion.
Personally, I believe the adjustment period into ketosis can be too long for some people to consider doing this on a weekly basis.
For the athlete, however, getting into the true metabolic state of ketosis is probably not the most important thing.
The focus is more likely on switching between glycolysis (conversion of glucose to pyruvate) to lipolysis and beta-oxidation (the breakdown and oxidation of fat) for ATP/energy generation via different pathways.
A targeted Keto Diet is even more specific than CKD because the carbohydrate feeding is done around workouts, and can be tailored for exercise intensity level and competition.
The general idea is to fuel with carbohydrates before, during and immediately after a workout, and follow a ketogenic lifestyle at all other times.
For me, this makes the most sense, if you want the best of both worlds. With this targeted approach you will be restocking liver glycogen and possibly some muscle glycogen, both of which are useful for energy provision and post-workout recovery.
All while being able to stay really low-carb.
Seasonal athletes sometimes follow a ketogenic diet in their off-season so they are not compromising intensity during their competing season.
Summary of Points on The Keto Diet
- The body uses a mixture of carbohydrate and fat as fuel by default
- Despite what many people think, glucose yields more energy than fat per volume of oxygen
- In carbohydrate depletion however, the body must rely more on fat for energy
- At a certain point of fat traffic through the liver, carb depletion and insulin inactivity (in some circumstances), ketones are produced by the liver
- Ketones are essentially packets of fuel which can travel to cells, organs and tissues that fat cannot
- Ketones are converted back to Acetyl-CoA in cells’ mitochondria, which is used in the citric acid cycle/Krebs cycle to generate ATP
- Glucose and fat also yield Acetyl-CoA during aerobic glycolysis and beta-oxidation respectively
- The liver itself cannot use ketones and needs glucose to store as liver glycogen. Red blood cells, certain parts of the brain and the kidneys also need glucose to function.
- In the absence of carbs, the process of gluconeogenesis generates glucose from non-carb sources such as glycerol and protein
- Gluconeogenesis is highly regulated and will not result in excess glucose production beyond that which is needed, even where excess protein is consumed. Hence it will not “kick” the body out of ketosis automatically
- It has been shown that progress in athletic performance will be impaired if the athlete is in a state of nutritional ketosis
- This applies to endurance athletes who are attempting to improve “fat adaptation” by following a chronic ketogenic diet
- Diets providing regular or periodized carbohydrate availability do not impair athletic performance and progress
- We can apply this to resistance training and other high-intensity training, perhaps even more so considering the reliance on the anaerobic system
- It may be difficult for ketogenic dieters to add lean body mass from resistance training due the appetite suppressive effects of the high-fat diet preventing them from attaining a calorie surplus.
- Even in calorie surplus, a ketogenic dieter may not be able to exert as much power given their lack of immediately available anaerobic fuel source; glucose, and muscle glycogen (stored glucose).
Who Would Benefit from a Keto Diet?
In my opinion a ketogenic diet would suit the following people:
- People who want to lose weight but find it difficult to stick to a calorie deficit with a carb-inclusive diet*
- Obese or near-obese people who struggle with blood sugar peaks/crashes and feel sluggish after carbohydrate consumption*
- Those who are purely interested in losing weight and not sport or exercise performance*^
- People recovering/rehabbing from Type II diabetes, provided a doctor has done full blood work to assess their body’s competence at dealing with certain fats with respect to lipoproteins and general cholesterol sensitivities.
*note that these issues could probably also be fixed with a diet that is more selective when it comes to carbohydrate choices
^the third point there is a contentious one for me because of the lack of exercise. Weight loss itself can be a medical emergency, and I understand cases where people are so morbidly overweight that exercise is not really a viable option until some mass has been lost.
BUT the vast majority of people who are considered obese, near obese, or those who simply don’t dig the thought of training (but still want to lose weight) usually diet for the simple goal of watching the number drop on the scales.
I’ll say this until I’m dead: weight loss, by definition, includes lean mass, especially muscle mass, unless you do something to preserve it. What good is getting lighter if you also become weaker?
High Protein Diets
People often tout high protein diets as a means to avoid ditching muscle mass, but it’s only partially helpful because you are still in an overall calorie deficit in order to lose weight.
That means you are spending more energy than you are consuming and if you lead a sedentary lifestyle on top of it, that energy deficit will start to manifest as fatigue.
Of course, the argument to that is: you still have to be in a calorie deficit to lose weight even if you are working out, so surely you will be even more fatigued.
My response to the arguments in favour of sedentary ketogenic dieting – actually any calorie deficit diet with a lack of exercise – is this:
If you diet without exercise you are still not conditioning your body to digest, process, allocate and store the macronutrients – or indeed the micronutrients – you consume, at anywhere near optimal efficiency OR efficacy.
Exercise, particularly a blend of resistance training and cardio-vascular training will not only optimize your body’s use of nutritional intake but will improve so many other facets of your health, including emotional well-being, immunity and general energy levels.
Improve Your Physique
Not only that but it will improve your physique and give you purpose to the dieting in the first place. Often people lose weight but don’t see much of an aesthetic difference in their physique. This is due to weight being lost evenly over the body at a slower rate than visual perception allows.
By meeting the weight loss with training-induced body compositional changes the transformation is much more dramatic and far more likely to engender the desire to continue.
Not only that, but physical training will shorten the time it takes to reach your goal bodyweight and therefore the time it takes before you can start consuming maintenance calories rather than a calorie deficit – and that’s an achievement.
So, taking all of that into consideration, the avoidance of carbohydrates becomes less and less important as you increase activity level.
Keto or no keto, exercise will accelerate your progress, and depending on the intensity level of your training, being in ketosis may actually start to inhibit your fitness gains.
Ketogenic Dieting combined with Resistance Training
There are people extolling the supposed muscle-preserving benefits of ketones and the notion that strength, muscle and fitness gains while following a ketogenic diet can be comparable to those made while following a carb-inclusive diet.
To me and many others, it’s impossible.
Ketones simply cannot supply the same energy requirements that glucose, glycogen and thus carbohydrates can when exercise intensity increases and oxygen demands can no longer be met.
This is because ketones can only be converted back to Acetyl-CoA, which then donates its acetyl group to the citric acid cycle. The citric acid cycle being that which is fed by beta-oxidation of fat and/or oxygen mediated (aerobic) gylcolysis (of glucose).
As exercise intensity increases and oxygen demands cannot be met, a greater energy load obviously shifts to anaerobic respiration. Glucose is the only source of fuel which can be converted to ATP via lactate in an oxygen independent environment.
For someone in ketosis to meet such energy requirements, sources other than carbohydrates must be converted into glucose via the process of gluconeogenesis.
The tax on the system corresponds to a lower energy payoff when compared to the relative efficiency of glycolysis involving dietary carbohydrates.
Furthermore, as I’ve already discussed, gluconeogenesis is neither a quick process nor one which will supply fuel indefinitely.
Converting protein or glycerol to sugars to facilitate high intensity exercise is akin to robbing Peter to pay Paul from a biochemical standpoint, and the human body just won’t allow it to happen for long.
To put this issue to bed, it would be great if a series of scientific experiments focused on direct comparisons of athletes following a ketogenic diet, a moderate carb-inclusive diet and a high-carb diet.
A mixture of men and women, both trained and untrained would be excellent.
A nice year long study would be fantastic, and if they could somehow blind the subjects to the diets they were on that would be perfect.
Of course, this isn’t going to happen anytime soon, and so we must rely on the data we do get.
Recently, one such study was published comparing the efficacy of ketogenic diet on body composition during resistance training in trained men.
The plan for the study was to have the subjects in a hypercaloric condition, i.e. a calorie surplus.
I’ll let you delve into the study I’ve linked to above if you want the specific design parameters etc. but one thing the scientists didn’t do too well was monitor the diet adherence.
As a result, the ketogenic group appeared to have experienced an unintentional calorie deficit, given they lose both fat mass and lean body mass (LBM).
The non-keto group on the other hand experienced a small drop in fat mass, but a significant increase in muscle mass.
Had the keto group maintained a calorie surplus the results would have been much more interesting, but they are nonetheless quite compelling.
Perhaps the most interesting outcome is that the ketogenic diet group, despite aiming for a moderate calorie surplus, lost weight.
This can be interpreted in two ways:
Ketogenic diets have an appetite/hunger suppressing effect and are therefore effective for weight loss
Ketogenic diets are not conducive to hypercaloric conditions and therefore not suited to people looking increase muscle mass.
The appetite suppressing effects of high fat diets are well documented and it comes as no surprise that this was the cause of the weight loss in the study, in spite of equated protein intakes and resistance training program.
What is surprising is that the scientists running the study simply stated in their conclusion that the keto group experienced no significant changes in lean body mass “despite hyperenergetic condition and high protein intake”.
The hyperenergetic condition refers to the calorie surplus. So the scientists themselves don’t point this out as a condition which can’t have been met, considering the (albeit non-significant) loss of fat mass and LBM.
This sort of conclusion might leave people wondering what magical effect keto diets have to cause fat loss even in hypercaloric conditions.
Instead, what should be focused upon is the obvious fact that the keto diet caused an unintentional calorie deficit.
Perhaps most telling result that is the carb-inclusive group (or non-keto group) lost a non-significant amount of fat mass but gained a significant amount of LBM.
Given they were training and eating high quantities of protein, this makes perfect sense.
In the end, this study was really a comparison of a calorie surplus carb-inclusive group and a calorie-deficit keto-group so you’re more than within your rights to throw it out as completely flawed. Hopefully, however, you can still see the value in it, regardless of its misgivings.
Mildly amusing to me is that the ketogenic group couldn’t eat a calorie surplus even when they intended to. That in itself puts a big dent in the whole “keto doesn’t compromise muscle gain” argument, in my humble opinion.
When you pair that with the race walker study from earlier, keto doesn’t seem ideal for endurance training either.
Should the keto athletes in the resistance training study have forced themselves to attain a calorie surplus, the results would have been very interesting.
Personally, I believe their lack of available glucose/glycogen for maximal output would have still hindered their potential for gains in lean body mass, but until a study is carried out that can investigate that in hypercaloric conditions we cannot know for sure.
Ketogenic diets and very low carb diets are not new, but they are in vogue, and it’s important to understand what following one means for your physical and emotional health.
“Low carb” diets don’t really have defined parameters. Many people assume that it refers to the more junky kind of carb rich food – high in sugar and low in nutritional value.
Donuts, cakes, white bread, white pasta, potato…those kind of foods. Those are examples of empty carbs more than anything. Reducing your consumption of them is just common sense.
Carbohydrates are actually abundant, and include food groups ranging from the simple, fast, processed-sugar-laden junk to fruits and vegetables. Sugars and starches come in different packages and forms, but they all fit in the general category of “carbohydrates”.
The definition of “low carb” is perhaps best described using a Ketogenic diet as an example, and then expand from there.
Ketogenic Diets Rely on the Formation of Ketone Bodies in the liver
These ketone bodies are often simply referred to as ketones, but the context is important if this is the case because “ketones” actually describe a lot of molecules.
There are 3 ketone bodies: acetoacetate, beta-hydroxybutyrate and acetone. The latter – acetone – is the product of breakdown of the two former ketone bodies. They are actually water-soluble chemicals, but “ketone bodies” will suffice.
The liver makes these three ketone bodies when blood insulin levels are low and blood glucagon levels are high.
This can be intentional, caused by very low carbohydrate intake (less than 50 grams per day), and unintentionally during starvation or through diabetes.
Nutritional ketosis, i.e. the intentional kind, is known as Ketogenic Dieting.
Carbs are your body’s primary source of fuel. When it has none left, it looks to fat to get its energy.
Fatty acids are released from fat cells and transported around the body to sites that need energy. Fatty acids cannot however be used by the Central Nervous System because they can’t cross the blood-brain barrier.
Ketone bodies can cross the blood-brain barrier and can therefore be used as fuel in the absence of glucose.
In fact, ketone bodies can be used by any cell with mitochondria for use as fuel.
Can a Keto Diet Cause Weight Loss?
They can, but only for the same reason any diet is able to: calorie restriction. By reducing carbohydrate consumption enough to trigger ketosis, people are usually eating less calories than they burn over the course of a day.
This is the primary reason for weight loss: Energy Out > Energy In.
One thing to consider is your ability to resist carbs at such a drastic scale. If you are constantly unhappy doing it then you will either remain so for as long as you can, or you will “break” and end up eating carbs, and possibly over-eating.
As with any weight loss diet, sustainability is the key. I try to advise a healthy, rounded diet that is 400 to 500 calories below your Total Daily Energy Expenditure (TDEE). That way you will likely feel less hungry (or downright crappy), you will be able to keep it up, and you will see the success.
Are Keto Diets Healthy or Unhealthy?
If there’s one type of diet than can be defined as “low-carb”, it’s definitely keto diets. Your liver knows pretty precisely what this means because when you eat under 50 grams of carbohydrate a day, it starts to build ketone bodies to replace glucose in your brain and central nervous system.
Think about what that means for a second. It means greatly reducing your vegetable and fruit intake, and it means losing all the whole food nutritional value that comes with it.
There are less extreme low-carb levels. The liver’s maximum storage capacity for glucose is roughly 150 grams, so eating less than that qualifies your diet as “low-carb”, while also allowing you to eat some healthy foods.
Intermittent fasting – where you eat regularly for a day and then fast for a day, or eat regularly for 5 days and then fast for 2 (the 5:2 diet) – is another way to trigger this process, albeit not constantly.
There are health benefits to intermittent fasting. Early evidence suggests life-extension may even be an advantage [https://www.ncbi.nlm.nih.gov/pubmed/24440038] of fasting because it can trigger some regenerative processes. Strong evidence in humans is still way off though.
Some people find intermittent fasting an easier way to lose weight. After all, they just eat normally when they do eat, and then simply don’t eat for a given time period.
Sometimes, simplifying things helps and avoids all the measuring and counting that is often the downfall of diets.
As for keto diets, and what is essentially an permanent state of intentional fasting, the jury is still out.
There are many products available that has associated themselves with the Keto diet process such as Pruvit Keto Reboot