There are many diets being marketed to the general public these days. We've got low-carb, no-carb, low-fat, high-protein, low-calorie, no-sugar, and the list. goes. on. We've even got widely recognizable names like Paleo, Atkins, Weight Watchers, South Beach, and, of course, Keto.
I want to focus this blog on the ketogenic diet, but we will touch on the basic principle of what makes a diet work, and that can be applied to all dieting methods.
Let's start with...
What IS the keto diet?
You may have heard to it referred to as a low-carb/high-fat diet, but that's not quite sufficient in describing it...
A ketogenic diet aims for almost net-zero carbs, moderate protein, and a very high fat intake with the aim of inducing ketosis within the body.
On a true keto diet your total carb intake would be somewhere in the realm of 50 grams or less of carbs/day, or about 10% of your overall caloric intake. (For reference, this is ~10-15 grapes. In an entire day.) Your protein intake would stay moderate at the recommended 1.2-1.5 grams per kilogram of bodyweight per day. And, lastly, your fat intake would come in at a whopping 60-80% of your total daily caloric intake. (For reference, a normal recommended 2000cal/day diet comes with the recommendation for ~30% fat.)
What is ketosis?
Ketosis is the whole goal of a ketogenic diet.
The almost-no-carb combination with a very high-fat intake reduces your bodies stored carbs. If you aren't taking them in you aren't saving them up. And, since the body preferentially uses carbs as its main energy source, when there is a lack of carbs it must find energy elsewhere. This is where all that fat comes in! The idea is that if you deprive your body of carbs but give it ample fats then it will be forced to use fat as its main energy source instead.
This has been shown to be true.
When your body uses fat for energy it goes through a long metabolic process to breakdown that fat and produce ketones which are then used for energy. These ketones circulate in the blood, and ketosis is a state of significantly elevated blood-ketones. So, we can tell if someone is in ketosis by the amount of ketones in their blood. And, if someone is in fact in ketosis, we know that their body is primarily "burning" fat (rather than carbs).
Is this healthy & safe?
Well, the short answer is sure. But the full answer is a little longer...
When your body goes into ketosis its normal metabolic processes are being altered. The body prefers to use carbs for energy. Then fats. Then protein. Then ethanol (yes, from drinking alcohol). And ketones for energy are on par with ethanol in this hierarchy. As Dr. Dixon and Dr. Kollias say, "just because we can metabolize something doesn't mean we should."
Take this to mean that if your body could choose, it would NOT be using ketones to produce its energy. It's not ideal, and it's certainly not the most effective metabolic pathway.
But, regardless, ketosis itself is not necessarily unsafe; just not instinctual by any biological means. And this whole concept is actually quite dated! It goes all the way back to the 1400's when it was observed that people suffering from epilepsy (thought it wasn't recognized as epilepsy at the time) experienced symptom-relief when abstaining from food and drink. Aka: starvation.
This concept was modernized in the early 1900's when we found that high-fat diets produced the same end result as starvation -- ketosis. That means, chemically speaking, starving yourself and following the keto diet look the same...
So, does it work?
This is perhaps the most important question. For a diet so restrictive (think about how many things you CAN'T eat if you can't eat carbs!) it must have some major benefits if people are willing to adhere to it. Right? ...Right...?
Well, actually, not really.
Ketogenic diets work in the way that all other diets work -- daily. caloric. restriction. #canigetanamen
And, interestingly, because of the nature of keto diets many studies have self-reported unintentional caloric deficits. This means that people on these diets have consumed less calories/day than they would have on a normal diet without even trying. This could be due to many factors but one supposed contributor is the satiation of the foods on a keto diet.
But, as compared to other diets, ketogenic diets do not show greater results for fat loss.
In fact, only when the protein content was significantly increased did the fat loss results of the keto diet also become significant. This leads one to believe that these results have more to do with the change in protein content than the adherence to ketogenic guidelines.
Additionally important to note: the stored form of carbs (glycogen) is relatively heavy compared to stored fat. It also carries a lot of water with it -- 3 parts water to 1 part glycogen, to be exact. So, when you restrict carbs you are eliminating those glycogen stores and the water that comes with them. This alone produces weight loss. VOILA! But it's somewhat of a facade since as soon as you eat carbs again that glycogen-related weight will come right back.
Ketogenic diets do NOT work in favor of sports performance or building muscle.
Studies have shown that while keto diets are effective in reducing fat mass (through restriction of total daily calories) they did NOT, even in a surplus, increase lean body mass.
Let's break that down... Since "calories in versus calories out" is the way to lose, gain, or maintain weight then that means two main things. (1) A caloric deficit will produce weight loss. We've already discussed this to be true for keto and other diet types. And, (2) a caloric surplus will produce weight gain. That weight could be gained as fat or as muscle, aka: lean mass. But, on ketogenic dietary restrictions, even when in a surplus LEAN MASS DID NOT INCREASE. This means that all of the weight gain produced was fat mass. And, THIS means that if you're on a keto diet and accidentally eating too much all you're gaining is fat.
Studies also showed that ketogenic diets produced no increase in performance but did result in a slight decrease. In contrast to this, high-carb (non-keto) diets led to a significant performance increase. This makes logical sense if you consider that carbs are your body's preferred fuel source, so when provided with them making energy is more effective, therefore energy is more abundant, therefore physical activity is better supported and performance has room to improve.
Other than diminishing your lean body mass and reducing your performance in the gym?
Yes, there is the potential harmful effect of ketoacidosis, which is an increase of blood-ketones to unsafe levels. This alters the pH of the blood and can potentially be life threatening. It is rare and probably not to be worried about simply from dietary choices. (Blood-ketone levels plateau ~2 weeks into a keto diet.) Ketoacidosis is a medical condition most common in those with type 1 diabetes whose bodies do not produce any insulin.
I don't mean to include this as a scare-tactic but simply to inform you that this IS something that exists. It's rare, but it's real. If it makes you weary I'd urge you to do your own research to determine for yourself if it's a risk you're willing to take (or if you'd even consider it a risk) if you're considering a keto diet.
An adverse effect that is more prominent is the incredible restrictiveness of this type of diet. You can't eat grains, breads, pastas, legumes, beans, fruits, oats, most processed foods, most deserts, most dairy products, and the list continues... And here's a pretty inclusive rundown of what you would be eating on a keto diet: red meat, bacon, and other fatty meats, butter, egg yolks, nuts, oils, avocado, and cheese.
It may sound great for, like, a meal or two. But as a sustained diet? Day after day? For weeks or months at a time? That's a lot of greasy, heavy fats...
And, lastly, there is the adverse effect of what's referred to as the "low-carb flu."
When you go into ketosis you will very likely experience the side effects of lethargy, digestive upset, bad breath, muscle cramps, sugar cravings, and drowsiness to name a few. Luckily, though, you can expect these symptoms to largely diminish over time as your body adapts.
These flu-like side effects combined with the restrictive nature of the diet result in very low adherence. This isn't necessarily an adverse effect, but it's certainly a drawback. Adherence to a diet is imperative in order to garner results.
Are there situations when a keto diet is recommendable?
Sure! If you have been suggested a keto diet by a medical professional for epilepsy, another neurological disorder, pre-diabetes, diabetes type 1 or 2, or something else your doctor thinks could benefit from the macronutrient ratios of a keto diet, then YES. By all means, follow the diet.
Since many of the foods on a keto diet naturally eliminate gluten, if you're gluten free and wanting to lose weight, keto may be perfect for you. As discussed earlier, keto DOES work to produce fat loss. (It just doesn't necessarily work better than other diet options.)
And, lastly, if you *like* the foods available to you on ketogenic restrictions and wouldn't mind taking out the grains and other carbs, then I see no reason why not to give keto a try. Again, the highly satiating effect of keto tends to produce a caloric deficit even unintentionally, so the diet does work for weight/fat loss. If it fits your preferences, go for it!
And, if keto isn't the answer?
That's a fairly limited list of situations in which a ketogenic diet may carry benefit over other diet types -- medical reasons, gluten restrictions, and/or basic preference. So, what other types of diets are there to try? And are they effective?
There are diets that adjust a certain macronutrient like keto does. You could try a more modest version of keto with a basic low-carb diet. Or, if that doesn't float your food-preference boat, you might try low-fat. If you're trying to build muscle while also dropping some body fat then high-protein is probably a better option for you. These diets would require nutrient tracking to make sure you're hitting the correct intakes.
There are also diets that don't worry about macronutrient ratios at all like intermittent fasting and IIFYM (if it fits your macros). These diets work solely on the calories in versus calories out principle without any regard for the composition of the foods being consumed. These diets would also entail nutrient tracking to ensure that total calories don't exceed a certain amount.
Then you've got diets based on rules such as 'no eating fast food,' 'no soda,' 'no alcohol,' gluten-free, dairy-free, vegetarian, etc. These diets are also based on restriction and work off of the calories in versus calories out principle but generally do not involve having to count the calories. Rather they rely on the set rules to naturally limit overall intakes.
And, lastly, there are hybrids of the options listed above. Say, a schedule of intermittent fasting with high-protein intake during feeding hours. Or, maybe IIFYM paired with the rule of no fast food, just to name a couple quick examples.
So much of dieting -- and especially doing so successfully -- comes down to personal preference, schedule, lifestyle, etc. If you pick a diet that doesn't jive with your life it probably won't last, and it if doesn't last then it most certainly won't work.
This article explores the facts and efficacy of low-energy (aka: low calorie) diets, low-fat diets, low-carb diets, keto diets, high-protein diets, and intermittent fasting. I definitely recommend checking out what it has to say about these diet archetypes as well as all the other great, scientifically based info it has to offer. :)
And, since that article leaves out the flexible dieting strategy of IIFYM, here's an entire book on the topic for your perusing pleasures!
IT PROBABLY WON'T HURT, AND IT MAY EVEN PRODUCE THE RESULTS YOU'RE LOOKING FOR.
- Keto diet works for the same reason other diets work: daily caloric restriction. But, they show no *benefit* in reducing fat mass over other types of diets.
- Medically recommended/supervised keto diets, those who are gluten free, and those who just prefer the foods on a keto diet would do well to give it a try.
IF YOU ARE AN ATHLETE OF ANY TYPE, TRYING TO BUILD/PRESERVE MUSCLE MASS, OR IF YOU DO NOT WANT YOUR PERFORMANCE TO SUFFER STEER CLEAR OF KETO DIETS.
- Ketogenic diets show performance reduction and even when eating a surplus of calories do NOT produce lean muscle mass.
OTHER DIET STYLES TO TRY IF KETO ISN'T THE RIGHT ANSWER FOR YOU:
- Low-carb, low-fat, high-protein
- Intermittent fasting
- Rule based
- IIFYM (if it fits your macros)