Your Guide to the Ketogenic Diet

By now, most of us will have heard of the ketogenic diet. It's been popularised by celebrities, promoted in best-selling books and is an ever-present feature on social media. In fact, in 2020 ‘keto’ was ranked the most Googled food-related topic in the world with 25.4 million searches.

Given this, you would be excused for thinking that keto was just another popular fad diet that has taken the world by storm and will soon give way to the next wave of popular diets promising rapid weight loss and impressive health benefits.

So, it might come as a surprise to discover that the ketogenic diet first became popular in the 1920s and 30s as a therapy for epilepsy. Back then, scientists observed that fasting was an effective technique for managing the condition. As promising as this would seem, fasting was obviously not a sustainable, long-term treatment option. Therefore, as a way of mimicking the metabolism of fasting, scientists developed the ketogenic diet.

For the better part of two decades, the ketogenic diet was used therapeutically to treat epilepsy. And, while this eventually gave way to epileptic drug treatments, the numerous benefits of the ketogenic diet were not forgotten.

Over the last 30 years, there has been a surge in research on the therapeutic and metabolic benefits of the ketogenic diet.

We now have a growing body of evidence demonstrating that the ketogenic diet is not only effective for losing weight but can also improve insulin levels, blood sugar regulation, appetite control, energy and endurance, brain function, hormone balance, inflammation as well as reducing risks associated with heart disease and type 2 diabetes.

As our understanding of the benefits of the ketogenic diet continues to grow we will likely see an expanding interest from both the scientific community and the wider public intent on adopting healthy approaches to weight loss and metabolic wellbeing.

The ketogenic diet is an eating plan that focuses on consuming plenty of healthy fats, a moderate amount of protein and very few carbohydrates. This allows your body to shift into a metabolic state called ketosis.

Ketosis is a process that happens when your body doesn't have enough carbohydrates to burn for energy. Instead, your liver uses fat, both from your body and diet, to make ketones. These ketones are then used for fuel, supplying a ready source of energy to your muscles, brain, organs and tissues.

In order to enter ketosis, you need to limit your carbohydrate consumption to around 20 to 50 grams per day and fill up on fats, such as avocado, nuts, fatty fish, olive oil, MCT oil and ghee.

Ketogenic diets can cause significant and desirable reductions in blood sugar and insulin levels. This, along with the increased ketones, has some noted health benefits.

These days, while many of us are keen to achieve our optimum weight, we want to do it in the healthiest way possible. It’s now recognised that quick weight loss programs and fad diets often come with certain health risks, including nutrient deficiency, metabolic imbalance and loss of lean muscle mass.

While going keto means you will be reducing your carbohydrate intake, that doesn’t mean you can’t choose from a wide range of healthy foods. In fact, the empty calories we typically eat in a modern carb-rich diet, are often replaced with fresh, nutrient-dense foods we otherwise wouldn’t eat.

That’s the first benefit!

Beyond this, the ketogenic diet has been shown to offer an impressive list of additional health benefits.

The ketogenic diet is one of the most researched strategies in recent years for weight loss. Numerous studies have shown that this nutritional approach has a solid scientific foundation and is able to induce effective weight loss, control hunger and may improve metabolic wellbeing (1).

Another study demonstrated that individuals who adopt a ketogenic diet achieve greater long-term reductions in body weight, diastolic blood pressure, and triglycerides, as well as improved cholesterol profiles, compared with individuals on a low-fat diet (2).

The fact that keto can also influence appetite makes this a standout consideration for weight loss.  Research has shown that individuals on the keto diet have increased levels of hormones, such as ghrelin, which induces appetite suppression, while also lowering hormones such as leptin, which stimulate our appetite (3).

If you decide to adopt a keto diet you can, on average, expect to safely lose around 0.5 - 1 kg per week. Importantly, you won’t only be losing belly fat, but also the visceral fat that accumulates around your organs that is associated with inflammation, heart disease, type 2 diabetes and insulin resistance.

Excess blood sugar can cause inflammation, cardiovascular disease, kidney disease, nerve damage, eye disease, and stroke.

A systematic review of 13 relevant studies found that the ketogenic diet not only improves blood sugar levels and glucose metabolism but can also reduce key markers associated with type 2 diabetes and pre-diabetes, as well as improve lipid metabolism (4).

High blood insulin increases the risk of obesity, type 2 diabetes, and cardiovascular disease and decreases life expectancy.

The first study assessing the impact of ketogenic diets on insulin resistance was conducted in 2005 and found that it may substantially improve insulin sensitivity in overweight individuals with type 2 diabetes (5).

A more recent study published in 2021 found that the ketogenic diet improves insulin resistance and might lower the risk for cardiovascular disease (6).

Type 2 diabetes is a metabolic disease that occurs when the pancreas doesn’t produce enough insulin, or when our cells don’t respond to insulin, resulting in too much sugar circulating in the bloodstream.

While diabetes can run in families, it is very much a lifestyle disease associated with being overweight, inactivity, high blood lipids and poor diet.

Several studies have shown that a ketogenic diet improves several markers associated with type 2 diabetes including insulin sensitivity, weight loss, haemoglobin A1C, blood sugar and body fat (7).

Based on the current evidence, the ketogenic diet has been shown to play a significant role in improving various factors associated with cardiovascular disease and has shown remarkable effects on cardiovascular function.

These studies suggest that the ketogenic diet is generally protective against obesity-related cardiovascular disease and improves risk factors like body fat, HDL (good) cholesterol levels, blood pressure, and blood sugar (7).

Numerous studies show that our brain, like our muscles, can become insulin resistant. This can affect mood and cognition and contribute to serious cognitive decline.

Alzheimer’s disease is now being referred to as type 3 diabetes.

On a ketogenic diet, ketones are the primary fuel source for the brain. They provide the brain cells with an alternative and arguably preferred energy source that significantly enhances brain function while reducing cognitive decline (8).

A ketogenic diet can be a worthwhile consideration for those that want to optimise their metabolism. The benefits extend well beyond weight loss and can address some of the key underlying factors associated with so many of the chronic diseases we see in our industrialised society.

Keep in mind, that for those who are trying to manage a health problem or disease, it’s important that you consult with a qualified healthcare provider.

1. Paoli A. Ketogenic diet for obesity: friend or foe? Int J Environ Res Public Health. 2014 Feb 19;11(2):2092-107. doi: 10.3390/ijerph110202092. PMID: 24557522; PMCID: PMC3945587.
2. Bueno NB, de Melo IS, de Oliveira SL, da Rocha Ataide T. Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trials. Br J Nutr. 2013 Oct;110(7):1178-87. doi: 10.1017/S0007114513000548. Epub 2013 May 7. PMID: 23651522.
3. Sumithran P, Prendergast LA, Delbridge E, Purcell K, Shulkes A, Kriketos A, Proietto J. Ketosis and appetite-mediating nutrients and hormones after weight loss. Eur J Clin Nutr. 2013 Jul;67(7):759-64. doi: 10.1038/ejcn.2013.90. Epub 2013 May 1. PMID: 23632752.
4. Yuan X, Wang J, Yang S, Gao M, Cao L, Li X, Hong D, Tian S, Sun C. Effect of the ketogenic diet on glycemic control, insulin resistance, and lipid metabolism in patients with T2DM: a systematic review and meta-analysis. Nutr Diabetes. 2020 Nov 30;10(1):38. doi: 10.1038/s41387-020-00142-z. PMID: 33257645; PMCID: PMC7705738.
5. Boden G, Sargrad K, Homko C, Mozzoli M, Stein TP. Effect of a low-carbohydrate diet on appetite, blood glucose levels, and insulin resistance in obese patients with type 2 diabetes. Ann Intern Med. 2005 Mar 15;142(6):403-11. doi: 10.7326/0003-4819-142-6-200503150-00006. PMID: 15767618.
6. Cara B Ebbeling, Amy Knapp, Ann Johnson, Julia M W Wong, Kimberly F Greco, Clement Ma, Samia Mora, David S Ludwig, Effects of a low-carbohydrate diet on insulin-resistant dyslipoproteinemia—a randomized controlled feeding trial, The American Journal of Clinical Nutrition, Volume 115, Issue 1, January 2022, Pages 154–162, https://doi.org/10.1093/ajcn/nqab287
7. Zhang W, Guo X, Chen L, Chen T, Yu J, Wu C, Zheng J. Ketogenic Diets and Cardio-Metabolic Diseases. Front Endocrinol (Lausanne). 2021 Nov 2;12:753039. doi: 10.3389/fendo.2021.753039. PMID: 34795641; PMCID: PMC8594484.
8. Rusek M, Pluta R, Ułamek-Kozioł M, Czuczwar SJ. Ketogenic Diet in Alzheimer's Disease. Int J Mol Sci. 2019 Aug 9;20(16):3892. doi: 10.3390/ijms20163892. PMID: 31405021; PMCID: PMC6720297.