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Just Ask Jase: Keto OS – Is it worth the hype?

Hi Jase,

I’ve heard a lot of talk and seen advertising for Keto OS and have a friend currently on a keto diet. Do ketogenic diets and supplements actually work for weight loss and performance?

– Keto Curious


A ketone body molecule.


Thank you for your question!

Keto OS is one of the most popular and vogue nutrition supplement ranges on the market at present, and they have really “tapped into” the Ketogenic Diet fanbase. Promising unrivalled energy, feelings of wellness, enhanced performance and wrapped up in an extremely impressive website and marketing campaign I really did sit back and enjoy the sheer quality of craftmanship that has gone into developing this movement.

The big question is though as you have asked me today, is it really worth the hype? Or does this resemble other large supplement product drivers such as Isagenix (please read our previous article on this topic)? Firstly, let me discuss with you’re the nutritional biochemistry behind the ketosis diet, and how these nutrition supplement products are claiming to provide you with the wealth of benefits I have listed above.

Ketosis is a state where to body shifts from primarily a glucose (carbohydrate) burning machine to where it relies on molecules called ketone bodies to fuel itself, which are derived from fatty acid breakdown (fats).

There are three types of ketones:

  1. Acetone: Produced to a lesser extent to the other two types of ketone, provides the “fruity smelling breath” reported with a ketosis diet as this is eliminated from the body when you exhale. These are actually toxic to the body, therefore you do not want a build-up within your system.
  2. Acetoacetate: Transported to your muscles, heart, kidney and brain as an alternative fuel source to glucose
  3. D-Beta Hydroxybutyrate: Similar to acetoacetate role and function within metabolism

Ketone bodies are generated in the liver as a response to “starvation” which is essentially a lack of carbohydrate from the diet or stores within the muscle and liver (known as glycogen).

It is very rare under “normal conditions” and a typical dietary intake that an individual would find themselves in producing a large amount of ketone bodies (the state of ketosis) however let’s just think of ketosis as where your body is burning fats for fuel (from the diet and also potentially from body fat stores). Furthermore, as we hold infinitely more body fat than carbohydrates (stored as glycogen) within the body, this is touted as a potentially limitless fuel supply for athletes!

Now I know that last part (burning body fat for fuel) grabbed your interest given the weight loss industry is so massive and ever-expanding. Let us delve into the weight loss and performance claims mentioned above!

Weight Loss: Research does indicate that using a ketosis diet can lead to rapid and significant weight loss overall, however the long term benefits have not yet been proven more effective that utilising a calorie controlled diet. The mechanisms behind this include the essential elimination of an entire macronutrient (carbohydrate) and the wealth of foods rich in this nutrient (therefore decreasing calorie intake).

Do not forget the initial rapid weight loss seen from carbohydrate restriction or elimination, as you lose stored carbohydrate (glycogen) and the water weight associated with this molecule.

Furthermore, the high proportions of fat within the ketosis diet (can be up to 80% total calories) is within itself rate limiting. By this I mean that if you consume too much fat in one sitting or overall, you will have some nasty gastro-intestinal side effects (nausea, diarrhoea and frequent loose stools). This too works to decrease overall calorie intake and therefore promote the calorie deficit we know we need to achieve weight loss (if you doubt this, have a look at the laws of thermodynamics)

Lastly, there are those that have reported an enhanced feeling of satiety (feelings of fullness) from such a high fat intake, which stands to reason as fat is very labour intensive for your gastro-intestinal system to break down. This could also lead to a decreased  calorie intake overall and again, the creation of a calorie deficit to support weight loss.

Performance: Ketogenic diets and performance have been another “hot topic” area that these keto-supplement products have well and truly laid claim to. Now where glucose was the primary fuel for activity (particularly higher intensity activity) via dietary carbohydrate intake and glycogen (stores of carbohydrates within the muscles and liver) there is always the limiting factor of just how much we can store or ingest to provide the rapid burning fuel we need.

Enter the fat hypothesis (ketogenic diets in particular) where we are primarily burning fats for performance fuel in the absence of dietary carbohydrate or glycogen stores. Given our body fat is such an abundant storehouse of fuels compared to what we can store via glycogen in our muscle and liver, it seems so very attractive to opt for the near “unlimited” fuel reserve.

What you are missing though, is just how fuels burn within your body. Despite the fact fat is a far superior sized tank of fuel for our bodies, burning this nutrient for your performance fuel is akin to putting diesel fuel into a formula one car. It does not burn efficiently, thereby limiting your performance (especially high intensity performance). Want some research behind this? Keep an eye out for a study coming in the near future called Supernova from Professor Louise Burke, Head of Sports Nutrition at the Australian Institute of Sport.

In the meantime, this link summarises what you should know about high fat diets such as ketogenic and athletic performance.

So moving forward, these supplements are designed and touted as a means to ingest ketone bodies themselves to get your body to start the “fat burning” process as a primary fuel source. Whilst the mechanism of ingesting therapeutic ketone bodies seem to be able to manipulate the body to prioritise ketone production for energy here are some points regarding excess ketones and your general health:

  1. Ketone supplements are quite costly, and you can achieve the state of ketosis with the correct nutrition manipulation. Si if this is your aim, do you really need them?
  2. Ketone bodies and the state of ketosis greatly increase the risks of a state called ketoacidosis, which can be fatal. At the very least, you are putting a heavier load on your kidneys to attempt to balance out the rise in blood acidity, which can cause damage to the kidneys themselves.
  3. Ketosis diets and ketone supplements can and have had a significant amount of reports of gastrointestinal complaints, from nausea, upset stomachs and the more common diarrhoea.
  4. Getting yourself into a state of ketosis (which at this stage has not been shown via research that these supplements can do alone) requires an extremely low carbohydrate intake (around 20 grams total/day) and just an adequate protein intake (as excessive protein can knock your body out of ketosis given that some amino acids can be converted to glucose if needed). Effectively elimination carbohydrate foods results in avoiding grains, fruits, most vegetables and most dairy foods. Cue an increased risk of constipation and vitamin and mineral deficiencies.
  5. Bone mineral density is compromised in an acidic environment, such as can be created from a ketosis diet or by ingesting high concentrations of ketone bodies. As this type of fuel does not burn cleanly (remember the diesel fuel for a formula one car analogy) we see an abundance of free ketone left to react with their extracellular environment and promote an acidic internal environment. Calcium has been shown to be leached from bone mass in these instances, thus compromising your bone health which can be disastrous long term (especially for females with osteoporosis risks ever present).

Whilst we continue to see some interesting findings from poorly designed animal studies regarding the effects of ketosis and the associated supplements, as a sports dietitian bound by evidence based practice I can say at present we do not have enough evidence to support their claims. We see a use for ketogenic diets in the role of epilepsy treatment and potentially Alzheimer’s management however the mechanisms are still not clear.

Watch this space, and remember you need an appropriate calorie deficit for your weight loss as a primary focus, and for those after optimal performance you really should be prioritising your carbohydrates given their clean-burning capacity. And as always, if you are in doubt about what nutrition approach may be right for you, contact our team of nutrition professionals at Enliven Nutrition today!


— Jase


Got a nutrition or training question? Or just want to know how to become better than yesterday?

Jason is the owner, resident sports dietitian and strength and conditioning coach at Enliven Nutrition. He specialises in sports performance, nutrition, weight management and strength conditioning training, and established Enliven Nutrition with the vision of providing nutrition and training programs that achieve any health or performance goal.




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