Guide
Interview: What can I still eat?
by Anna Sandner
Weight loss: can ketones really turbocharge your metabolism?
3.6.2025
Translation: Katherine Martin
Ketones are said to be turbo fat-burners that help you lose weight. But is there any truth to the claims? Read on to find out what ketones actually are, how they work and what risks you should be aware of.
The dos and don’ts of a keto diet
The cornerstone of a ketogenic diet is eating as few carbohydrates as possible, focusing instead on consuming lots of fat and moderate amounts of protein. This is what triggers your body to switch to burning fat. Basically, that means you can eat plenty of avocado, eggs, fish, meat, cheese, nuts and green vegetables, all of which provide you with key nutrients and keep you in ketosis.
High-fat foods such as olive oil, coconut oil or butter, which cover your fat requirements, are the main component of a keto diet. Green leafy veggies such as spinach or broccoli are ideal as they hardly contain any carbohydrates and provide plenty of vitamins.
As far as keto no-nos are concerned, you should steer clear of carbohydrate-rich foods such as bread, pasta, rice, potatoes and most types of fruit, including bananas, mangoes, apples and pears. Sugary foods and sweets are off the menu, as they quickly raise your blood sugar and prevent ketosis.
And as a matter of fact, there’s no scientific evidence for any of these effects in humans. The few studies that do exist have only been carried out on animals, and even those results are disputed. If you choose to take magic pills you’ve bought online, you’re taking a real risk. Products like these can have unpleasant or even dangerous side effects, including raising blood pressure or putting increased strain on the heart.
What’s more, many of these capsules and powders aren’t even approved in Europe. They’re considered untested, novel foodstuffs – which is exactly why countless products have already been pulled from the market.
The consumer rights watchdog hits the nail on the head by saying: «We can’t gauge the risks, the benefits are unproven – and raspberry ketone products are anything but a secret trick to achieving a slimmer waistline.»
As bread, fruit and many vegetables are removed from the diet, this can lead to a deficiency in fibre, vitamins and minerals (website in German). Potential consequences of this include constipation, muscle cramps and skin problems.
Diets very high in fat can also damage the cardiovascular system in the long run. There’s evidence they can raise blood lipid and cholesterol levels, in turn increasing the risk of cardiovascular disease.
So, if you switch to a ketogenic diet, you should pay attention to what your body’s telling you. You should also review your nutrition regularly, preferably with professional help.
Header image: Nok Lek Travel Lifestyle/Shutterstock
Anna Sandner
Senior Editor
Anna.Sandner@galaxus.deScience editor and biologist. I love animals and am fascinated by plants, their abilities and everything you can do with them. That's why my favourite place is always the outdoors - somewhere in nature, preferably in my wild garden.
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