This revolutionary diet is reportedly more than just a weight-loss tool – many people are now espousing it as the solution to other health complaints.

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This revolutionary diet is reportedly more than just a weight-loss tool – many people are now espousing it as the solution to other health complaints.

Barely had breakfast and your stomach’s already rumbling? If you only had jam on toast, or a croissant, that is not surprising, as it gets digested very quickly. Due to that, the body wants energy right away. To get this, it tends to want fast-acting energy sources, such as sugary carbs. Except these are precisely the foods that prevent us from losing those extra kilos, maintaining our weight, and staying healthy. So, how do we break this vicious circle? By eating fat to lose our fat, claims Dr Markus Bock, a neuroscientist and doctor specialising in metabolic diseases. With a recent study conducted by the Technical University of Munich and the University of Vienna confirming this theory, we speak to Dr Bock to find out more. 

The keto diet is about eating fat so as to break down fat. Doesn’t that sound like a contradiction? 

“Fat doesn’t make us fat. That’s one of the biggest misconceptions in nutrition. We gain weight from carbohydrates like bread rolls, potatoes and pasta. They programme our body to put on weight by stimulating the release of insulin, the ‘fattening hormone’.” 

And fat works differently? 

“Yes. This is evident in the differences between the way the body metabolises fats and carbohydrates. Dietary fats are broken down in the gut and split into fatty acids. The longer their chain, the longer this takes. But this doesn’t result in an extreme rise in blood sugar. Carbohydrates are broken down into glucose in the gut, whose cells suck the sugar directly into the blood using special pumps. This creates an energy explosion of sorts. If you eat a croissant made from white flour, it will be digested extremely quickly, and the energy will instantly be supplied – whether you need it or not.” 


What happens to me in the space of 24 days?

2 Days: During the first few days, our body goes through veritable withdrawals as glycogen from the muscles is broken down and glucose is not replenished. This is known as ‘keto flu’, as it is accompanied by symptoms such as headaches and weakness. Meanwhile, the ‘cellular power plants’ are converted to ‘fat’ fuel.

7 Days: Many people lose two or more kilograms in the first week, but it’s more water than fat. In the body, glycogen is stored with water, so once it’s broken down, we automatically also lose fluid. 

14 Days: Now, the body has almost completely converted sugar to fat for energy supplies. The first real boost in energy and performance occurs between week 2 and week 3. Our metabolism can also start burning body fat now.

24 Days: In ketosis, weight loss of 2 to 3 kg a week is realistic; the higher the body-fat percentage, the greater the loss. As we’re allowed to eat anything except carbs, this makes us feel nicely full for prolonged periods.

KETO TIP: Many fruits and veggies contain some carbs as well as many vitamins and minerals, so it’s important not to cut them out of your diet altogether.

And what happens then? 

“We either use the energy supplied because we walk 10 kilometres straight away, or we transfer it to our glycogen stores, which are primarily in the cells of the liver and muscles. In most people, however, these stores are always full due to our carbohydrate-rich diet.” 

Where does this excess energy go?

“Most of it goes into the fat cells. Because when we consume carbohydrates, the body reacts to the increased blood-sugar level by releasing insulin. On one hand, this channels energy into the cells in the form of glucose, but on the other, it also ‘opens’ our fat cells. Anything that isn’t used is then stored in there by our body.”

When does our body release energy from fat cells?

“When the body sees fat cells reserve as the easiest way of getting energy. However, as long as there is sugar from carbohydrates, the body will not draw on its fat stores.”

How do I empty the fat deposits?

“An increased intake of good dietary fats and a reduction in sugar intake can trigger the body’s natural weight-loss process: Ketosis. The glycogen stores are first broken down, which can only happen with consistently low insulin levels. This is like an alarm signal for the cells, alerting them that a critical energy shortage may be imminent. The fat cells thus reopen and release the fatty acids inside them. The liver turns these into ketone bodies like acetoacetate. These can be good food for the brain, heart and almost all the cells as they are a source of constant energy that’s not dependent on insulin. What makes this so important is that many lifestyle diseases cells have been found to be insensitive to insulin.” 

If fat is so much better for us, why does our body still want sugar?

“Because sugar has long been a product in short supply – even up to just 100 years ago. That’s why the body is so crazy about it. And also because it’s really addictive. Our cells are actually optimised for fat – this hasn’t changed in tens of thousands of years. The cells’ powerhouses – the mitochondria – work more effectively with a high-fat diet. They are much better able at reducing the body’s own process of forming radicals, and multiply much faster than with a high-sugar diet.”

Are all calories the same?

“No. If we consume 1,000 kilocalories of protein, our insulin concentration barely increases. Yet, insulin doubles when we consume 1,000 calories of carbohydrates – with big consequences for our waistline: Insulin opens the cells so they can absorb sugar from the blood. At the same time, insulin closes the fat cells so the body cannot burn fat.”

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What to eat – and what’s better avoided

Use the table to put together your own keto diet. The main thing to bear in mind is the ratio of carbohydrates to fats. Always pay attention to ingredients and check the values in a nutrition table.

From top, left to right:


Walnuts, almonds, and pumpkin seeds are particularly high in fat, so eat no more than 50 g a day. 


Due to its high sugar content, many fruits are not keto-compatible, particularly, bananas, grapes and mangoes. Berries, lemons and limes are better. And in no more than two to three handfuls a day. If in doubt, always check a fruit’s fructose content. 


When it comes to cheese, the higher the fat content, the better. Consume no more than 100 g a day, and cut out ‘light’ products. Avoid milk or similar as much as possible; they’re very high in carbohydrates. Opt for plant-based alternatives such as almond milk. 


Some vegetables are higher in carbohydrates than others. You can fill your plate with vegetables that are low in carbohydrates such as eggplant, cucumber, onions, zucchini, capsicum, spinach, asparagus and white cabbage. Lettuce, bok choy, rocket and radicchio are also keto-friendly. 


Olive oil, avocado and organic full-cream butter with no added rapeseed oil are all high in health fatty acids. Perfect as a spread or for cooking. 


Cold-water fish, such as sardines and salmon are high in protein, and EHA and DHA omega-3 fatty acids. Red meat, poultry and eggs are ideal for keto, too.


The good thing about keto is that almost everything is allowed without any major quantity restrictions. Here is a quick overview of foods to avoid: Bread, sugar, milk, grains (think rice, pasta and oatmeal), starchy vegetables such as potatoes, beans, peas and yam.


The number of grams represent the maximum recommended daily quantity.


Protein (100 g)

Carbohydrates (50 g)

Fat (150 g)


Protein (75 g)

Carbohydrates (20 g)

Fat (180 g)

What about our brain, the organ which needs the most energy, and ‘screams’ for sugar when under stress? 

“Give (the brain) some good fat! [Healthy fats] have a positive effect at the root of stress in the brain, and can reduce our susceptibility to it. When we follow a ketogenic diet, the brain changes its transmitter capacity, meaning increased production of messenger substances like gamma-aminobutyric acids, which cushion brain cells. This benefits epilepsy patients, too. In cases of mental strain, the rise in stress-hormone levels will no longer overstimulate nerve cells – and we react more calmly. As a comparison, a high-sugar diet causes stress in the system, causing lasting damage to cerebral metabolism.”

What does fat do for Alzheimer’s?

“We know sugar can cause a lot of damage to nerves and vessels because it can easily overcome the barrier between blood and brain. But I follow a different approach: I believe sugar changes the balance in messenger substances, which results in the loss of important neurotransmitters for our learning capacity, recall and memory. A ketogenic diet can prevent this from happening. Unlike fats, ketone bodies can enter the brain directly, and unlike glucose, which first needs to be converted several times, ketones can be absorbed directly by the neurones as food.” 

What other positive effects does a ketogenic diet have on our body? 

“Sugar is like doping for cell division, but it stimulates the growth of both good and bad (i.e. cancer) cells. Ketogenesis normalises the cell metabolism and inhibits tumour growth. The glucose-fat balance also plays a key role in inflammation – the big research topic of our time – because sugar irritates the vascular system. A diet high in fats and proteins serves to soothe here too.” 

How can I successfully follow a keto diet? 

“I advise a moderately ketogenic diet – no more than 50 g and no less than 20 g of carbohydrates a day. Good fats are important. Naturally healthy foods, like vegetables and berries, has a certain amount of carbohydrates. So, if you reduce your carbohydrate intake by just 10 g, for example, you’re counting out all natural seasonal foods. Then, you’ll be restricting yourself more than necessary and may end up resorting to lower-quality industrial products.” 

How long do I have to persevere?

“Speak to your doctor first if you’re planning on following a ketogenic diet long-term, but you can maintain the diet for three to six weeks, and repeat it regularly throughout the year, for positive effects.” 

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There is some evidence to suggest that the Keto diet can help with the following things: 

BRAIN Reduce the frequency and severity of migraine attacks, improve brain function and mood swings, have a positive impact on depression, and help with epilepsy autism and Alzheimer’s.

HEART Reduce the risk of cardiovascular diseases. 

STOMACH Reduce issues like heartburn in the case of gastroesophageal reflux disease (GERD).

FERTILITY Regulate sex-hormone metabolism and increase likelihood of conception. 

CELLS Normalise cell division, inhibiting tumour growth. 

NERVES Reduce the body’s inflammatory reaction to pain, which improves chronic complaints. 

SKIN Fight inflammatory processes which contribute to acne, eczema, psoriasis and rosacea. 

KEEP IN MIND It does come with its benefits, but the keto diet isn’t for everyone. Side effects can include digestive issues like diarrhoea or constipation, muscle loss, leg cramps, fatigue, irregular menstrual cycles, and ‘keto breath’. Consult your GP before commencing the diet.