13. Sep, 2018

Why you should avoid a ketogenic or very low carb diet

OK, so that heading was a bit of clickbait, I admit it. Now that I have your attention though, it's time to have a balanced conversation about low-carb diets.

We are constantly being told that even a small amount of weight loss is good for us, and that is true. But how that weight loss is achieved is often overlooked, and the long term consequences need to be considered. 

The Ketogenic Diet is an accepted therapy for hard to treat paediatric epilepsy which has been in use for almost 100 years. It has come and gone in different fad diet guises such as Atkins, the Zone, Sugar Busters,  Dukan etc, but it was never really meant to be used by the general population.

Much of the weight loss achieved particularly at the beginning of low-carb diets is water, which is used to flush out ketones generated by stored fat breakdown, and excess amino acids from the high protein intake. 

What are ketones? 

Ketones are made by your liver to protect your brain against starvation, a state mimicked by a low-carb diet. The brain is designed to oxidise glucose but adapts to use ketones in such an emergency. 

We now know that traditional (high protein, usually high red meat) low-carb diets increase your cardiovascular disease and diabetes risk, despite the fact that they can reduce your blood glucose levels and help you lose weight. You need to, forgive the pun, 'weigh up' if the weight loss is worth the increased risk of premature death. 

What does the evidence say? 

In a 2014 study using data from over 6,300 adults (<65yo), researchers at the University of Southern California investigated the link between protein intake and mortality (premature death) over an 18 year period. Specifically they looked at how low, medium & high protein intake affected diabetes and cardiovascular mortality, as well as cancer risk. 

  • Low protein was <10% of daily calories
  • Moderate protein was between 10-19% of daily calories
  • High protein was >20% of daily calories

Low carb diets are normally between 20 to 35% daily calories from protein, which is even higher than what was seen in this study.  

The results were scary, and the numbers too big to ignore. Among those without diabetes already, the high protein group had a 73 times (7300%) increase in risk, while the moderates had an almost 23 times (2300%) increase in the risk of developing diabetes. In comparison, high blood pressure has been found to increase the risk of developing diabetes by 60%. 

The high protein group were also four times as likely to die of cancer when compared to the low protein group. 

Animal protein made up the majority of the protein consumed, and the researchers theorise that plays a major role into the extent of the increased risk of premature death. 

How much protein should you eat in order to try to avoid cardiovascular disease or diabetes? 

The Australian guidelines recommend the estimated average requirement for adults (excluding pregnancy & lactation) is between 37 (women) and 52 (men) grams per day. This is probably much less than you thought it was, right? We have had a lifetime of marketing by the meat industry to convince us we need to eat it daily in order to meet our protein needs. It is simply not true. 

All plants contain protein, there is no reason why you can't meet your  intake requirements from vegetables, fruits and dairy or dairy alternatives, with the richest sources being legumes, beans and nuts.  Pescatarians get most of their protein from seafood, a far healthier choice than red meat. 

Fad diets do not work in the long term. They are great for fast, short-term weight loss, a kick-starter if you like. Really good for eliminating cravings, but ultimately unsustainable, because we are human and like food that tastes good and/or is seen as 'forbidden'. Instead of obsessively carb or calorie counting, you need to establish a long term healthy relationship with food. Simply being mindful of what and how much you are consuming, and eating whole foods as much as possible is key. 

You can get the support that you need from a university-qualified nutritionist. We will never unnecessarily cut out groups of foods for a prolonged period of time, because we don't see any food as inherently 'bad'. 


Emdin CA, Anderson SG, Woodward M, Rahimi K 2015, 'Usual Blood Pressure and Risk of New-Onset Diabetes', Journal of the American College of Cardiology, vol.66, no.14, pp:1552–62.

Levine ME, Suarez JA, Brandhorst S, Balasubramanian P, Cheng C-W, Madia F, et al 2014, Low protein intake is associated with a major reduction in IGF-1, cancer, and overall mortality in the 65 and younger but not older population', Cell Metabolism, vol.19, no.3, pp:407–17.

National Health & Medical Research Council 2014, Nutrients - Protein, <https://www.nrv.gov.au/nutrients/protein>.