How High Fat/Low Carb Works for Diabetes

clock and food

Diabetes is one of our biggest and most expensive health problems, and there is a desperate need for a more effective treatment.

Currently, around 3.2 million people in the United Kingdom have been diagnosed with type 2 diabetes, but this figure is increasing by 5 per cent every year. The direct cost to the NHS is nearly £10 billion -10 per cent of its total budget.

The UK first issued guidelines recommending a low fat, high carb diet in 1983. Since then, millions have followed the official advice, yet diabetes and obesity have increased exponentially. With the benefit of hindsight, this was inevitable because the government was trying to treat a disorder involving excessive levels of sugar and insulin with a diet that causes both to rise several times each day.

Drugs have been developed to combat the disease, but these are mostly designed to allow patients to continue to eat a high carb diet by reducing blood sugar levels pharmacologically. If you like cake, the usual advice is to increase your dose to compensate!

Surely, it would be a better idea simply to reduce your intake of carbohydrates, which would result in an automatic reduction in your insulin level – a driver of many of the key symptoms of diabetes, including weight gain, insulin resistance and chronic inflammation?

This approach is recommended on the website (not to be confused with the official charity Diabetes UK, which is at

Dr David Unwin’s Low Carb Approach

The site was a revelation to Dr David Unwin, a GP from Lancashire. He was amazed to read the testimonies of patients who were enthusiastic about the high fat diet and reported some astonishing results: 5–6kg lost in a few months; glucose and insulin levels right down; no need for drugs. ‘To be honest,’ Unwin says, ‘I had begun to despair of being able to do much for my patients with diabetes. Most found it very hard to lose weight, so I’d start by warning patients that if they didn’t control their blood sugar and weight with diet, they would have to go on drugs. But nutrition was never my field, so I’d send them to the dietitian, who would advise a low fat, high carb diet.’

Inevitably, this approach almost always failed, so Unwin looked for an alternative and advised nineteen of his patients to follow the low carb, high fat diet he had seen on the diabetes website. This entailed drastic reductions in their consumption of starchy bread, rice and pasta as well as sugary products. By the end of the eight-month trial, only two of the patients still had high glucose levels, but even these had declined substantially. The participants lost an average of 9kg, their blood pressure was lower, and they experienced significant improvements in their levels of gamma-glutamyl transferase (GGT), an important indicator of liver health.

Diabetes UK responded to Unwin’s findings, which he published in 2014, by declaring that there was insufficient evidence for the ‘long-term safety’ of the diet. As such, it ignored the fact that the National Institute for Health and Care Excellence (NICE) recommends a version of the low carb diet for children with severe epilepsy, which they are advised to follow for years.

Next, Unwin turned his attention to the two different types of carbohydrate – those that raise blood sugar rapidly (high GL) and those that release their sugar gradually (low GL). He advised diabetics to consume only low GL carbohydrates and saw ‘significant improvements’ in diabetes control and weight, while spending around £40,000 less per year on diabetes drugs’.

Such findings have ‘totally changed the way we run the surgery,’ says Unwin. ‘Now I collaborate with diabetic patients on their problems with weight. I ask them about their goals and what they hope to achieve. If I get involved with what they are doing, they often surprise me with the changes they are prepared to make.’

By 2017, his practice had cut its drugs bill by £50,000 a year, and over 200 of his fellow GPs had joined an online low carb group to share advice and findings. Since he started recommending the low carb, high fat diet, 46 per cent of Unwin’s diabetes patients have achieved drug-free partial remission.

Low Carb for Insulin Resistance

A low carb diet also seems to be highly effective in combating insulin resistance – a serious condition that is associated with pre-diabetes as well as diabetes itself. The effect is similar to addiction – your body needs ever more insulin to get the same effect as cells become less and less responsive to the hormone. As a result, weight, blood pressure and blood glucose all increase.
The pancreas reacts by secreting even more insulin, which has damaging effects throughout the body. In response, the insulin resistant fat cells start to send out inflammatory chemical messengers (cytokines), which inflame the cells’ mitochondrial power plants. The end results are chronic tiredness and accelerated ageing.

However, a number of recent scientific studies have found that a high fat diet can help to arrest or even reverse this process. The largest and most impressive of these trials involved 262 diabetic patients who were restricted to 30g of carbs a day for two years. Meanwhile, most of their energy needs were met by an increased intake of fat. At the start of the study, the average HbA1c level (a marker of how high their blood glucose had been recently) was 7.6 per cent, but after ten weeks 50 per cent had a level of 6.5 per cent, meaning they were technically in remission.

Similarly, at the beginning of the trial, nine out of ten participants were taking at least one drug; by the end, more than half had either reduced or ceased their medication altogether. Moreover, they probably felt far more content throughout the two-year experiment, because another study reported a ‘significant decrease in the psychological stress associated with diabetes management alongside a reduction in negative moods between meals’.

The Ketogenesis Pioneers

While David Unwin advocated the careful control of carbohydrates, plenty of diabetic patients and a few clinicians were prepared to go much further by reducing their carb intake to as little as 20g a day, while increasing their consumption of fat. In short, they adopted a full-blown ketogenic diet and forced their bodies into ketogenesis.

Ketogenesis is the body’s natural response to starvation. Once the body has exhausted its limited reserves of glucose, it first converts protein from our muscles into glucose, which is used to fuel the brain.

However, this is not a good long-term solution, given that we need our muscles as well as our brain, so the body soon switches to the production of ketones. These are made from fat that is released from storage in response to the critical carbohydrate shortage, and they are a perfect source of energy for both the brain and the muscles. The body still needs a small amount of glucose on a daily basis, but this can be manufactured from protein.

That’s why it’s important to eat plenty of protein if you are on a high fat diet. Inducing ketogenesis through starvation is a fairly unpleasant process, and obviously it cannot be sustained for very long. By contrast, the ketogenic diet is a way of achieving precisely the same effect without the pain and for an indefinite period of time. Lowering (or eliminating) the carbs causes the shift while the extra fat in the diet stops the hunger.

For these pioneer diabetic patients and clinicians there was no more calorie counting, but they had to abandon all of the low-fat staples, including skimmed milk, ready meals with added sugar, and starchy foods, such as bread and potatoes. These foodstuffs were replaced with plenty of meat, poultry, fish, eggs and full-fat cheese, along with unlimited amounts of cream, avocado, coconut oil, seeds, nuts and olives (and their oils).

Extracts from The Hybrid Diet (Piatkus, 2019). For more details of research in this area please see the book. References for the book available on the 5 Day Diet page under The Science and Testing.


Do listen to my podcast The Low GL Revolution on this subject with Dr David Unwin.

My Hybrid Diet

Inspired by the research and case studies, in 2019 I wrote the book The Hybrid Diet, with award-winning medical journalist Jerome Burne explaining the theory and some practical information so you could create your own keto diet combined with a low GL maintenance diet.

Unlike the Atkins diet, we focus on all kinds of fatty foods not just meat so suitable whether you’re carnivorous or vegetarian – but without carbs. Think avocado, halloumi and salmon. We show you how to enjoy slow carbs so you don’t have to shun all pasta and bread. The Hybrid Diet explains why, when and how to switch, and provides you with the simple and delicious recipes you need to do it.
For example, on a high fat day you can start your day with a Hybrid Latté made with no-carb almond milk, almond butter, coconut butter, coffee, cacao and cinnamon and lunch on a delicious pesto butter sautéed spinach with salmon.

On a slow carb day you could have a slice of carrot and walnut cake as a snack and, for dinner a big bowl of chestnut and butterbean soup with oat cakes, both made in 5 minutes.

Switching regularly between slow carbs and high fat you become ‘carb adapted’ – craving less sweet foods, and ‘fat adapted’ – able to burn and derive energy efficiently from fat. It’s like nutritional yoga as your metabolism becomes more flexible.

The 5 Day Diet

I followed up The Hybrid Diet with the more prescriptive 5 Day Diet in 2020.

If you think you’d like to try a diet based on this new science, and if you are pre-diabetic or diabetic and want to discuss them with your health practitioner or nutritionist – these books are available from HOLFORDirect.

The 5 Day Diet is FREE with the supplement combo needed to get cracking with the diet – or the book is available on its own.


If you want to read what others who have done the diet have to say about it you can read their testimonials here.