Keto Diets

The ketogenic approach to eating is the hot dietary topic right now, having taking over from the paleo trend of a few years ago (demonstrated by Google Trends). As you can see from the graph below, searches for 'keto diet' overtook 'paleo diet' earlier this year.

Google Trends offers a great insight into what people are searching, and talking, about when it comes to diets and nutrition. Further, when a diet search term exceeds 'weight loss diet' (generic diet search term) this is a good sign that people are hearing about that diet from other people and then looking to Google to learn more. It's a sort of 'buzz measurement'.

To be fair, ketogenic and paleo are quite similar – high fat and protein, and low carbs – so we aren't comparing chalk and cheese (chalk isn't paleo). People transitioning from paleo to keto might explain why the paleo search term begins to drop while the keto search term increases.

While the macronutrient intake may be similar between these two diets, the underlying philosophy is quite different.

Paleo is a throwback to our caveman years, where our digestive evolution allegedly halted. Plenty of meat, fish, eggs, and vegetables, with the exclusion of grains. Paleo is the nutritional equivalent of #flasbackfriday, although you have to follow it every day. 

On the other hand, the push for ketogenic is coming from some exciting research for health and diseasestates, albeit without strong links to body composition.

But before we deep-dive into ketogenic diets and their potential applications, we should outline what ketosis actually is.


What is Ketosis?

Ketosis occurs when the body has insufficient carbohydrate availability relative to requirements. Glucose is the primary fuel source for the brain, as fatty acids and amino acids cannot cross the blood-brain barrier to be used as fuel.

Therefore, when the glucose supply is restricted the body must transition to its backup brain fuel: ketones.

Ketones are produced from fatty acids, in the liver. This process is known as ketosis. The ketone bodies enter the bloodstream and are able to cross the blood-brain barrier, to provide a fuel source for the brain.

Moving into ketosis requires very-low carbohydrate availability, such as during prolonged exercise, sustained low-carbohydrate intake, and starvation.

During ketosis, fatty acids become the primary fuel source for the body, in the absence of glucose. 


Potential Benefits of a Ketogenic Diet

Burning Fat

If glucose availability is so low that ketosis has been initiated, then stored fatty acids will also be the predominant energy source for the bodies functioning. Therefore, a higher proportion of fat will be oxidised for fuel, relative to when glucose was present. This means that more stored fat can be mobilised and oxidised as fuel.

However, it is important to realise that there is still a balance between intake and expenditure. Although you are oxidising more fat for fuel, compared to non-ketogenic conditions, body fat will still accumulate if energy intake exceeds expenditure.

In addition, fat is typically consumed in higher quantities on a ketogenic diet, in place of carbohydrate. So while fat mobilisation might be increasing, so is intake.

The balance between intake and expenditure will determine whether fat is stored or lost - which is the standard principle of body composition.


Ketogenic diets focus on high-fat and protein-based foods, such as plenty of eats, meat, fish, etc.

An increased protein intake can help with feeling full between meals and help protein muscle mass during an energy deficit (ie. lose a higher ratio of fat:muscle).

Therefore, an increased protein intake might help you consume less energy, due to feeling full between meals. In addition, if more muscle mass is maintained during the energy deficit, body composition changes can be more noticeable.

Health Benefits

Ketogenic diets have purported benefits for brain function, some diseases, and cancers. It's not my place to recommend any diet for these reasons, however, this does provide the context for why keto is so intriguing right now. 


Potential Drawbacks

Ketone Management

Ketone accumulation in the blood can lead to ketoacidosis, a potentially life-threatening condition.

Ketone levels can be monitoring us a prick blood test, similar to diabetes management. However, is that something people are willing to manage?

It begs the question - if someone was unwilling/unable to control overall energy intake previously, how will they fare with the practical application of managing their ketone levels?

Probably not well.

Nutrient Intake

Key micronutrients, and fibre, can be hard to attain on the ketogenic diet. This can lead to nutritional deficiencies, if maintained for an extended duration.

However, anytime adherence is a drawback or challenge, I think the worry about nutritional deficiencies should be taken with a grain of iodised salt. Becuase if people cannot stick to it, they won’t get the associated deficiencies.


Eliminating an entire food group brings challenges, particularly for people who currently lack a structured dietary intake. Food choices become quite restricted to achieve the low-carbohydrate intake.

It begs the question - if someone was unwilling/unable to control overall energy intake previously, how will they fare with the practical applications of eliminating carbohydrates?

Again, probably not well.


The Biggest Question

Is the ketogenic diet superior to other forms of energy restriction for body composition?

When protein and overall energy intake are matched, ketogenic diets have no demonstrated benefit for body composition compared to any other diet. This is based on current research, which is somewhat limited.

For that matter, when protein and energy intake are matched, all diets appear equal. This means that if you stick to any combination – with carbs or without – and results will be the same.

Therefore, the ketogenic diet does not appear to be superior to any other form of energy restriction for body composition, based on the information at hand.

My Thoughts

The ketogenic diet is definitely the latest and greatest diet, and it is receiving plenty of attention in the media and via search.

I think there might be some exciting benefits for disease and cancer, which could lead to nutrition-supported treatments in the future.

However, from a pure body composition perspective, I think it’s no different to anything else. I think it's harder to adhere to than other dietary approaches, which will lead to low-adherence and failure. At the end of the day, adherence is all that really matters.

I think the keto approach is too hard, overly eliminatory, and complicated.

Maybe it would work for someone who had done well following a paleo diet in the past. However, even then, I don’t think it would be my first port of call.

Let's hold tight and stick to creating an energy deficit via reduced energy intake and some exercise. That means if keto is proven beneficial in the near-future, you will have a solid base of nutrition habits to help you adhere to any new system. Not that you will need to!