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The ketogenic diet, or keto diet, has become increasingly popular in recent years. Despite being unconventional compared to most other diets, many people claim to have achieved their weight loss goals because of it. But what exactly is the keto diet, how does it work and is it something you can incorporate into your health & fitness routine? We answer all your most commonly asked questions right here, so you can make an informed decision about giving it a try.  

What is a keto diet? 

A keto diet is based on very high-fat food. More specifically, those who follow a keto diet should get most of their calories from fats (about 70-80%), a small part from proteins (10-20%) and as little as possible from carbohydrates (less than 10%). Normally, your body prefers to use carbohydrates (in the form of glucose) from food or stored glucose (in the so-called glycogen supply) as an energy source. When you limit carbohydrates from your diet, it will need to find an alternative source of fuel. So, your body enters a state of ‘ketosis’, where it burns fat instead, potentially leading to weight loss. 

Get most of your calories from fats (about 70-80%)
Get a small part of your calories from proteins (10-20%)
Get as little as possible of your calories from carbohydrates (less than 10%)

Is the keto diet the best way to lose weight? 

It is indeed true that most people will lose weight on the keto diet. This, however, is partly due to water loss when the body starts to use glucose (sugar) reserves from the liver and muscles. As glycogen stores also retain moisture, you will tend to urinate more and hence lose weight. However, as Body&Fit ambassador Shelly explains in her blog about losing weight, losing weight is not the same as losing fat. To lose fat you need to be in a calorie deficit for a prolonged period of time. Technically, this is of course also possible with the keto diet, but then you have to pay attention to more factors than your carbohydrate intake alone.  

“Most people will lose weight on a keto diet, but will they also lose fat?”

Can I build muscle on a keto diet? 

When you think about building muscle, protein is probably the first thing that comes to mind. What if you want to go after those gains on a keto diet, where it’s all about consuming fat? Well, this study of men who exercise regularly showed that muscle mass increased when ten weeks of keto eating was followed by reintroducing carbohydrates for 2 weeks. Other studies show that there is no significant change in muscle mass when following a keto diet. The most important thing to remember is to keep your calorie intake high. After all, you’re asking your body to make extra tissue and mass, which requires energy. You’ll still need to eat enough protein (on your plate and possibly supplemented with a shake) and of course train regularly. Our Body&Fit Whey Isolate XP is a good way to supplement your proteins without a lot of carbohydrates. One serving of this shake contains only 0.5 grams of carbohydrates versus 25 grams of protein.  

What are the side effects of the keto diet? 

When you’re just starting a keto diet, it can be a drastic change to the way you eat. As it involves excluding a large group of food, it can be difficult to get enough vitamins, minerals and fibre. So, it is likely that you’ll experience some side effects. The general keto rule for carbohydrate consumption is a maximum of 50 grams per day. One banana already contains about 30 grams of carbohydrates. This is why fruit is often skipped in the keto diet. There are, however, lots of important vitamins, minerals and fibre in fruits. The same applies to healthy carbohydrate-rich products such as whole meal bread, pasta and couscous. We always recommend following the guidance of a dietitian or doctor for this reason.  

“The general keto rule is to consume a maximum of 50 grams of carbohydrates per day. One banana already contains about 30 grams of carbohydrates.”

Side effects that can occur with keto are described by some as the flu, and the symptoms are indeed similar: 

  • Headache 

  • Fatigue 

  • Craving certain food 

  • Vertigo 

  • Difficulty concentrating 

What can you eat with the keto diet? 

Make room for fats! A ketogenic diet consists mainly of:  

What should you not eat on the keto diet?  

Simply put: all carbohydrate-rich foods are avoided as much as possible with the keto diet. These are the main ‘forbidden’ foods of the ketogenic diet: 

  • Sugared drinks: soft drinks, fruit juice, smoothies. 

  • Sweet snacks: pastries, ice cream, sweets. 

  • Cereals: wheat products, rice, pasta. 

  • Fruits: almost all fruits, except for some berries and strawberries in small quantities. 

  • Legumes: peas, kidney beans, lentils, chickpeas. 

  • Root crops: potatoes, sweet potatoes, carrots, parsnips. 

  • Sauces high in sugar: ketchup, sweet chili sauce. 

  • Alcohol. 

The keto diet, summarised 

The ketogenic, or keto, diet consists of a lot of fats and very few carbohydrates (up to 50g per day). Due to the shortage of carbohydrates, the body goes into a state of ‘ketosis’, where it switches to burning fatty acids, instead of glucose, as an energy source. The keto diet can also be combined with an energy-restricted diet that allows you to lose weight. For most people, it is not a permanent diet because of the strict restrictions. We therefore recommend seeking the advice of a dietitian or doctor before and during a keto diet.  

In the meantime, our dedicated team of Nutrition Experts are always ready to answer your questions regarding nutrition, diets, and our leading range of sports performance and lifestyle products. Check out our advice, recipes and workouts pages for further information and follow us @body&fit_official for fun fitness tips, advice, delicious recipes inspiration and more.