What is a ketogenic diet?

Sometimes called the ‘keto diet’, we explore whether the diet is safe and ask if it works.

Find out more:


An update to our advice on ketogenic diets.


Full disclosure: I’m into my 3rd year of keto and I absolutely love it. It was a life-changing discovery for me.

Firstly, two weeks is far too short for an evaluation. Your body takes time to adapt to ketosis and burning fat for fuel. I didn’t enjoy my first few weeks on it. It certainly had a big impact on my exercise performance, which didn’t recover until about month 3 or 4. After that, I saw big improvements.

I also found it odd that only 1.5kgs were lost? This doesn’t seem like enough as you should lose a bit more than that in water weight alone when your body goes into ketosis. So I wonder if something was a bit off? Restricting carbs is very difficult at first because they have snuck their way into just about everything, so they may have been hiding in some foods. If you’re doing an experiment to write up, it’s probably important to test for blood ketones to verify that carbs have been kept low enough for the body to enter ketosis. (not that I’d recommend this for everyone starting keto, as they’re not really necessary)

I think it’s important to consider the work of scientists in this area, not just dietitians. The Dietitians Association of Australia (DAA), until very recently, was heavily conflicted with very close ties to industrial food manufacturers. Not so long ago you had one of their spokespeople recommending Up’n’Go as a great breakfast for kids. I think their cosy relationship with manufacturers has influenced their education and training, to become a dietician you need to DAA accredited course. They’ve recently taken steps to distance themselves from industry, so hopefully, we’ll see better work from them in the future as more low-carb/keto studies are done.

Sure I might sound like a crazy person, but there is plenty of evidence. Indeed, here we have an extract from the Australian Breakfast Cereal Manufacturers Forum targeting Choice specifically for astroturfing. Leveraging their partnership with the DAA.

Some items counter to the DAA official advice regarding keto and carbohydrate restriction.

Research from the CSIRO (admittedly they’re pedalling a book of the back of it): https://blog.csiro.au/low-carb-diet-scientifically-proven/

A recent WA parliamentary enquiry - The Food Fix: The role of diet in type 2 diabetes prevention and management: “There is convincing evidence to support the use of dietary interventions such as the very low calorie diet and the low carbohydrate diet in the treatment of people with type 2 diabetes.”

You even have the head of the American Diabetes Association completely off insulin as a result of carbohydrate restriction.


My question about the Keto diet is WHY???

And I have a massive amount of exposure to it, literally half my family have been Keto for the last year.
The biggest thing I’ve noticed with them is that every single one has undergone marked personality changes, and they all look really pale all the time for some reason.

Eat food, real food, mostly plants, not too much (and in ways that dont make you feel restricted so its easy to keep doing) and move lots (so you’re expending a little bit more energy than you consume) is far easier than Keto and if you stick to it and get help from the pros (trainers, GP, dieticians) you can lose as much weight as keto.


Great question.

The advice of everything in moderation has been pushed for a long time with substantial backing from vested interests (Hello coke and their shonky in 2015 https://www.choice.com.au/shonky-awards/hall-of-shame/shonkys-2015/coca-cola-company) and certainly works for a lot of people. But I, and many I know, find this advice simply doesn’t work in practice. Believe me, I’d love nothing more than to be able to enjoy the odd ice-cream or bowl of pasta with the family. When I’m out of ketosis I simply cannot control my appetite. This is fine when I’m exercising 15+ hours a week, but not fine with anything less. Ketosis, for me, gives me far greater control over my appetite and the freedom to control what I eat. I don’t find it restrictive, I relish the freedom of having control.

Most Australians would be well aware of the advice to eat food in moderation, most Australians are overweight and I don’t think they want to be. Something clearly isn’t working with the moderation advice amongst smart & well-educated people. Could the advice flawed? What’s wrong?

Of course, this is anecdotally just me, but side from the main benefit of appetite control/weight, I’ve also found:

  • I sleep really well, I can barely remember what it was like to be frustrated trying to fall asleep.
  • I don’t snore – could be due to the weight?
  • My blood pressure has fallen dramatically – weight related?
  • My bodyfat % is down. Muscle % is up.
  • I used to suffer badly from restless leg syndrome, it was horrible and it has vanished.
  • My cycling performance has dramatically increased. I can ride for hours without needing to eat, and still manage to sprint repeatedly at high intensity (the repeat sprinting ability took ~12 months into keto).
  • Being out of ketosis just feels awful, I feel bloated, lethargic and my nose blocks up in minutes. It’s hard to describe, I just have this energy when I’m in ketosis.

Why not?

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I do admit, eating well on a mainstream diet does involve a huge amount of self-discipline, and it’s a big learning curve. You have to learn what portions and serving sizes are, and you have to learn to stop at one measured serve of ice cream instead of a huge bowl, or four squares of chocolate instead of a whole block. You eat the burger, but pass on the coke and large fries.

The big problem with “everything in moderation” is that most people are really poorly educated about what “moderation” is. Consumerism is geared so far the opposite of true moderation that the word “moderation” has come to mean whatever the individual thinks it should mean. Its an easy thing to see with alcohol - how many people do you know who throw around the word “moderation” about drinking, while drinking far more than the recommended two standard drinks (which is the well-evidenced true definition of an upper limit of moderation when it comes to alcohol)? Food is the same. Maybe the extremism of restrictive diets like the Keto diet make it easier to follow because its a far more concrete concept than “moderation”.

So I eat a mainstream “healthy” diet (which is fairly mediterranean because I LOVE pasta and olive oil) - everything in actual moderation. In the beginning it was a strictly “calorie counted”, portion-measured diet matched to my activity levels, but after the first six to twelve months it became intuitive and I have to think a lot less about it. I lost 25kg in the first year, and have maintained that for a further year and a half so far, which I feel is more impressive than losing it to begin with. After losing weight I:

  • slept better
  • stopped snoring
  • had a lot more energy
  • body fat percentage went down, muscle percentage went up (the weightlifting had a bit to do with that!)
  • the more and longer I have trained, the better my running stamina and performance has gotten.

I think you’re potentially confusing the effects of loss of excess weight and gains as you train in general with keto.

Keto food always makes me feel awful. Its actually getting to the point where I am bringing my own food to family meals because every time I eat their fat-laden greasy keto meals I get horribly sick.


An article advising people to count macronutrients instead of kilojoules.

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Yes, I’ve tried to take those into account where possible.

Here is my performance statistics over the past few years. I started Keto early in 2018 after my weight blew out to 100kgs when I became a father and couldn’t train very much.

Year Kms FTP (watts) Notes
2019 9,417 333
2018 4,038 263
2017 7,886 274 became a father in August
2016 9,430 261
2015 5,323 241

The best comparison would be 2016 against 2019 with almost identical Kms and very similar circumstances, although much more sleep deprived in 2019. Yet my Functional Threshold Power (FTP, an estimate of your maximum sustainable power output over 1 hour) went through the roof at 333 watts (or 4.11watts per Kg). When I compare my power curves it’s also higher across all time periods. I cannot find another explanation for this except for long term training in ketosis and a validation of how much stronger I feel on the bike.



Australian of the Year Dr James Muecke promoting low-carb and highlighting the results of the Virta Health Ketosis Study.

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I wonder how you separate the improvement from simply a gain in muscle mass with training.

Don’t you need two groups to be certain? A control group on a more conventional diet and one on a ketogenic diet.

Both groups need to be large enough to be statistically significant, of similar genetic characteristics and starting condition, and follow similar lifestyle and training plans.

I’m not disagreeing with the need to exercise or the short term benefits.

Some of the world wide examples of communities with exceptional longevity have dietary practices very different from those of a ketogenic diet. And no aggressive exercise, but steady physical activity. One of the BBC series with Dr Mosley looked at diet and it’s effects on ageing, with a very different take on diet preferences. I’ll post a link when I find it.


I wonder how you separate the improvement from simply a gain in muscle mass with training.

No idea, but my weight fell too. So power-to-weight increased even further and I was setting a lot of personal bests at the end of 2019. Initially, on keto my performance suffered greatly. I had almost no energy for 3 weeks and getting out to ride the bike was a huge struggle. Then I returned to my usual strength after 6-7 months and beyond that it kept on improving.

Don’t you need two groups to be certain? A control group on a more conventional diet and one on a ketogenic diet.

Interesting point you raise and my experience is certainly all anecdotal (in statistics we call it an n=1 study). It’s certainly not a scientific study and it wasn’t a randomised clinical trial, where you would take a group of people and allocate them to different diets, then observe what happens. It was just me changing my diet and tracking my cycling.

That Virta Health study is a clinical trial, patients with diabetes have been randomly assigned to receive their usual care, or care which promotes a ketogenic diet. Which is probably why you should look at those results, rather than my experience.

As a statistician by training, I find the whole field of nutrition research rather frightening. Our dietary guidelines have been based on very poor epidemiology, this is what Dr James Muecke is arguing in the article I shared above. Because it’s just so difficult to conduct them properly, our eating guidelines have not been based on long term clinical trials, but by making observations and asking people what they think they have been eating (epidemiology). I understand why it’s been done, but it’s (clearly) not a great basis for making dietary guidelines.

The guidelines aren’t working.


I’m not farmiliar with Dr Mosley or his BBC series, but a lot of research has been made into the areas with the largest numbers of those living beyond 100. With various advice to live like they have lived; Drink, don’t drink. Exercise, don’t exercise. Eat more veggtables and okinawan sweet potato etc etc.

Some new research which came out in 2019 is very much worth a read:

Take no dietary advice at face value!

A short version from the ABC.

And the original BBC series reference. I’m not sure how accessible this is to some from the UK. It was last shown in Australia several years ago SBS and appears available still from SBS On Demand.

It’s not intended to provide an alternate solution for special dietary needs such as those with diabetes. It too asks questions of the inconsistencies in observed health outcomes in different groups.


Three recent studies, one RCT, a Meta-Analysis of RCTs and a non-random control trial.

Aug 2020

Effects of weight loss during a very low carbohydrate diet on specific adipose tissue depots and insulin sensitivity in older adults with obesity: a randomized clinical trial

Conclusions Weight loss resulting from consumption of a diet lower in CHO and higher in fat may be beneficial for older adults with obesity by depleting adipose tissue depots most strongly implicated in poor metabolic and functional outcomes and by improving insulin sensitivity and the lipid profile.

July 2020

Impact of a Ketogenic Diet on Metabolic Parameters in Patients with Obesity or Overweight and with or without Type 2 Diabetes: A Meta-Analysis of Randomized Controlled Trials

The effects of ketogenic diets on glycemic control were greater for diabetic patients relative to those of low-fat diets, indicated by lower glycated hemoglobin (SMD, −0.62; p < 0.001) and homeostatic model assessment index (SMD, −0.29; p = 0.02), while comparable effects were observed for nondiabetic patients. Ketogenic diets led to substantial weight reduction (SMD, −0.46; p = 0.04) irrespective of patients’ diabetes status at baseline and improved lipid profiles in terms of lower triglyceride (SMD, −0.45; p = 0.01) and greater high-density lipoprotein (SMD, 0.31; p = 0.005) for diabetic patients. Other risk markers showed no substantial between-group difference post intervention. Our study findings confirmed that ketogenic diets were more effective in improving metabolic parameters associated with glycemic, weight, and lipid controls in patients with overweight or obesity, especially those with preexisting diabetes, as compared to low-fat diets. This effect may contribute to improvements in metabolic dysfunction-related morbidity and mortality in these patient populations.

June 2020:

And an article (non-random control trial) claiming keto is bad for athletes.
Crisis of confidence averted: Impairment of exercise economy and performance in elite race walkers by ketogenic low carbohydrate, high fat (LCHF) diet is reproducible

this study was able to investigate (and disprove) a hypothesis based on anecdotal observations about successful performance in athletes

The study is an extremely short duration (1 month) investigation into the ketogenic diet for elite race walkers. 3.5 weeks into the ketogenic diet and my exercise performance was trashed. Study itself seems to be of high quality, but that part of their conclusion based on this study doesn’t seem justified. But I would say that, wouldn’t I :slight_smile:

Do agree that the following could be very interesting

The potential models involving periodisation of CHO availability, or alternatively, the integration of high CHO availability within a background of keto-adaptation are numerous, and also merit investigation.


November 2020

Insights from a general practice service evaluation supporting a lower carbohydrate diet in patients with type 2 diabetes mellitus and prediabetes: a secondary analysis of routine clinic data including HbA1c, weight and prescribing over 6 years

Conclusions This approach to lower carbohydrate dietary advice for patients with T2D and prediabetes was incorporated successfully into routine primary care over 6 years. There were statistically significant improvements in both groups for weight, HbA1c, lipid profiles and blood pressure as well as significant drug budget savings. These results suggest a need for more empirical research on the effects of lower carbohydrate diet and long-term glycaemic control while recording collateral impacts to other metabolic health outcomes.

Focus is on the cost savings that have been achieved with a low carb approach to diabetes management, as opposed to a drugs first approach.


Robert J. Ostfeld, MD, MS, Professor of Medicine (Cardiology) at Massachusetts General Hospital has recently raised concerns about Keto diets, and "As a cardiologist, I believe the keto diet is a mistake,” and “The keto diet, I believe, is based on misinformation.”

A recent interview with Robert J. Ostfeld, MD, MS, has been posted on Youtube and is worth watching for those which are interested:


As i watch the video, the first two things…

The Innuit populations now have the same rates of heart disease since they’ve introduced other foods, few of them now eat as they’ve done in the past. His statement is correct but very misleading.

“if you look at the longest living populations in the world”
The number one correlation between the number of centurians per pop is… poor record keeping.

With two misleading claims right up I’m finding it hard to continue with the video. Screams to me like he has an agenda of some sort.


Something more to consider.
SBS has a short and very recent documentary series.
Michael Mosley’s Health Intervention.’ Available to stream for convenience if one chooses.

Irrespective of diet preferences it tackles some very common health concerns in an easily understood and followed format. The impacts and where calories (kJoules) come from could not be any clearer. There is some good advice too about not embarking on a diet without getting appropriate medical assessment and support.


Time for some keto / low-carb updates.

  • Virta Health releases 5 year study outcomes. - June 2022

Using low carb for diabetes treatment, pretty amazing results and over a very long period of time.

Sustained blood sugar control. Virta patients experienced persistent improvements in blood sugar on average, while requiring significantly fewer medications.

Medication deprescription. Half of patients prescribed insulin at the start of the trial no longer needed it at five years. Across all diabetes drugs, prescriptions were reduced by nearly 50%.

Weight loss. Average weight among Virta participants decreased by 7.6%, exceeding the 5% benchmark for clinically significant weight loss by more than 50%.

Broad improvement in cardiometabolic health. In addition to improvements in triglycerides, HDL cholesterol, and markers of inflammation, patients even showed encouraging signs in reversing the progression of chronic kidney disease.

  • The American Diabetes Association has released low carb treatment options for adults with diabetes.

The American Diabetes Association has identified low-carbohydrate (LC) and very low-carbohydrate (VLC) eating patterns as options that can improve outcomes in adults with type 2 diabetes. This 28-page guide was designed to assist registered dietitians, certified diabetes care & education specialists, and other health care practitioners in assessing the appropriateness of a LC or VLC intervention for their patients. Additionally, it provides strategies and sample meal plans for implementing a LC or VLC eating pattern as an evidence-based intervention in adult with type 2 diabetes.

  • Even Diabetes UK now has low carb meal plans.