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Keto diet - what is it?

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If you’re looking to lose some weight, you’ve probably spent time researching different diets. In its most simple form, a diet is where you consume fewer calories – according to the NHS, the average person looking to lose weight should eat 600 fewer calories each day.

More complex diets put a lot of emphasis on the types of foods that you eat. In some cases, a diet will severely limit or restrict certain food groups, like carbohydrates. This sort of restrictive diet can prevent you from getting all the nutrients your body needs. It’s best to seek guidance from a healthcare professional when following a food plan like the ketogenic (or “keto”) diet as they may not be suitable for everyone as an effective or safe way to lose weight.

What is the keto diet?

A ketogenic diet is one that includes very few carbohydrates, and a high amount of fat. The aim is to keep your blood glucose at a safe but low level. This encourages weight loss via ketosis, a process where the body burns fat for energy.

Because a keto diet keeps blood sugar low and burns fat, it’s thought to be a helpful approach for people who need to lose weight. It can be especially beneficial for people who have type 2 diabetes or those who are at risk of it.

A keto diet is also thought to do the following:

Is the keto diet safe?

A ketogenic diet can be safe, but it’s important to get all the nutrients your body needs. This means you’ll need to be very careful about what you eat. Before you start following a ketogenic diet you should talk to your doctor to make sure it’s safe for you, and that you have all the information you need.

People who may not be suitable for the keto diet include:

What can I eat on a keto diet?

The keto diet is low on carbohydrates, high in fat, and includes a moderate amount of protein. There aren’t any keto diet rules that are set in stone, and the precise guidance will differ depending on who you talk to, and what your health history is.

As an example, for people with diabetes who are looking to lose weight and maintain healthy blood sugar levels, Diabetes.co.uk recommends the following keto diet plan:

  • Less than 50g of carbohydrates per day
  • Around 40-60g of protein per day (40-50g for women, 50-60g for men)
  • Non-starchy vegetables with every meal
  • Plenty of fat

You may also want to supplement your diet with specially prepared foods and drinks that are low in carbs and high in fat, such as the SlimFast Keto range. Just bear in mind that these types of supplements should be enjoyed as part of a healthy and balanced diet.


Protein is important on a keto diet, and can come in the form of meat, fish, eggs, dairy, nuts, and pulses.

However, you only need a moderate amount because if you have too much the body can end up converting it into glucose. If you’re struggling to lose weight on a ketogenic diet, you may need to cut back on how much meat you’re having.

Non-starchy vegetables

Vegetables are a great source of essential nutrients. However, they also contain carbohydrates. If you’re trying to follow a keto diet, you have to be careful about which types you eat.

Fruit and starchy vegetables like potatoes, sweetcorn, and beetroot contain the most carbs. Non-starchy vegetables like broccoli, cabbage, lettuce, cucumbers, carrots, mushrooms, and tomatoes contain the least carbs.

Find out more by reading the section below: Which foods contain carbohydrates?


Fat is generally “free” on the keto diet, meaning you don’t have to restrict your intake. Incorporating high-fat, plant-based products can be a good way to get plenty of fat without too much protein – olive oil and avocados are two good sources of vegetable fats.

Another way to get fat on a keto diet is to eat fatty cuts of meat, poultry with the skin on, and dairy products like butter and cream. This is one of the ways in a which a keto diet is different to the diet recommended by the NHS. Fatty cuts of meat and high-fat dairy products are sources of saturated fat, and are generally thought to be bad for your health when eaten in large quantities.

Which foods contain carbohydrates?

If you’re considering a keto diet or any other diet low on carbs, it’s a good idea to read up on carbohydrates. When we talk about carbs, we tend to think of bread and pasta – but the truth is, carbohydrates are present in all kinds of food.

Carbohydrates are one of three macronutrients (alongside fat and protein), which means they make up a huge part of our diet. They contain many of the vital nutrients that we need to stay strong and healthy.

The three types of carbs that are found in our diet are sugar, starch, and fibre:

  • Sugar occurs naturally in fruits, vegetables, milk, and honeys and syrups. It’s also added to products like chocolate, sweets, biscuits, cakes, and fizzy drinks.
  • Starch is found in bread, rice, pasta, potatoes, and cereals.
  • Fibre is found in fruit, vegetables, pulses, and wholegrain varieties of bread and pasta.

The most important carbohydrates are whole fruits and vegetables, pulses, and starchy foods that are high in fibre. These are all really beneficial for your health and shouldn’t be completely cut out.

If you’re looking to reduce the carbs in your diet, the best area to cut back is on sugars – and particularly free sugars. Free sugars are any sugars that are added to snack foods, fizzy drinks, and desserts. The naturally occurring sugars in unsweetened fruit juices, smoothies, and syrups are also considered to be free sugars.

I’m struggling to lose weight. What should I do?

Losing weight can be a challenging and time-consuming process, and you won’t always see instant results.

The best way to lose weight is to commit to eating fewer calories and exercising more regularly. If you need support, the NHS offers a free 12-week diet and exercise plan.

For some people, diet and exercise aren’t effective on their own, and medication may be appropriate. If you have a BMI of 30+, or a BMI of 27+ and  have a condition that’s been made worse by weight gain such as type 2 diabetes, hypertension or sleep disorders, you might be eligible for our weight loss service.

Weight loss service