Is the keto diet the best for weight loss?

We’re back with another debunking popular weight loss diets series! This time we’re doing the keto diet. The aim of these posts is to give you the facts to make informed choices about what you eat. You can read my previous debunking of a low fat diet here.

What is the keto diet? 

The ketogenic diet is a very low carb, high fat diet. It typically involves less than 50g of carbs a day. For reference, the recommended intake for carbohydrates is 260g a day. It can also be expressed as a ratio – so your diet is 10% carbs, 20% protein, and 70% fat.

A hand holding half an avocado. The other half of the avocado is on the table.

The science behind the keto diet is that by not consuming carbs, your bodies main energy source, it will use fat for energy instead. After a few days of keto, your bodies glucose stores are depleted, and the body is looking for something else to fuel it.

It begins to break down the fat stores and creates ketone bodies to be used as energy. This is called ketosis. The idea is that this then leads to weight loss, as you’re using up body fat for energy.

Is the keto diet the best for weight loss? 

Research has shown that following the keto diet can lead to significant weight loss when compared to other diets, like a low fat diet.

However, there isn’t enough long term information about whether this weight loss is maintained. People tend to regain some weight after a while. So more research would be needed. And the people in the studies we do have find it difficult to stick to the keto diet. By the end of the studies, some people were consuming more carbohydrates than the 50g allowance.

person standing on scales

Negatives of the keto diet: 

While the keto diet can lead to weight loss, there are many pitfalls.

Deprives the body of glucose: 

Glucose is the body and brain’s main energy source. Your brain takes up 2% of your body weight but uses 20% of the energy. Your brain needs a lot of energy to function! The brain can also use ketone bodies for energy, but glucose is preferred.

Unsustainable and restrictive: 

The keto diet is highly restrictive as it’s a very low carb diet. It involves limiting bread, rice, pasta, other grains, potatoes, beans, some dairy products, fruits, and some vegetables. Its restrictive nature can make it very difficult to maintain in the long term.

An assrtment of carbohydrate containing foods - pasta, cereal, vegetables, and nuts
I know I couldn’t cut out these foods for the rest of my life. I tried to follow a keto diet for one day and couldn’t get to less than 50g of carbohydrate. It adds up so quick! You can see how I got on on my Instagram as I saved it as a highlight on my page @kaegoskitchen.

Nutrient deficiencies:

With the diet being so restrictive in what you can eat, there’s a risk of nutrient deficiencies. The keto diet can lead to deficiencies in: magnesium, potassium, selenium, calcium, fibre, the B vitamins, and vitamin C. This can lead to a whole host of problems as all of these nutrients are essential for bodily health.

The ‘keto flu’:

Following the keto diet and drastically reducing your intake of carbs can lead to lots of unpleasant symptoms. This is because it can take your body a while to adjust to not using its preferred energy source of glucose. This is so common that it’s been nicknamed the keto flu. It can lead to headaches, irritability, nausea, fatigue, and constipation to name a few.

Benefits of keto: 

Here are a few positives for the keto diet.

Management of epilepsy:

The ketogenic diet was originally created for use in children with epilepsy. By following a keto diet, children can see up to a 90% reduction in seizures. It works by reducing the excitability of the brain and making a seizure less likely to occur.

Less ultra-processed foods: 

crisps on a white plate
Another benefit of the diet is that you’re more likely to eat whole foods. As most ultra-processed foods, think baked goods, sweets, and crisps, would be high in sugar and carbs, they’ll be avoided on the diet.

In my post about processed foods, I wrote about how a diet high in ultra-processed foods can increase the risk of obesity and other diseases. As the keto diet restricts these foods, it could reduce the risk of some diseases. But you can still get ultra-processed keto friendly products too like keto cookies by the Skinny Food Co. So, it’s not a guarantee.

Cholesterol levels:

There are also some studies that suggest that a very low carb diet can improve the levels of cholesterol in the blood. One small study found that keto lowered the levels of TAG. A high TAG (triacylglyceride) level can indicate a risk of heart disease.

There are some positives of the keto diet, but whether it’s worth all the downsides is another question. If you’d like to lose weight without a drastic reduction in carbs, my previous blog post here gives some tips.

Key points:

  • A ketogenic diet is a very low carb, high fat diet. The aim is to have less than 50g of carbs a day.
  • By not consuming carbohydrates, your body uses fat for energy – this is called ketosis.
  • Following a keto diet can lead to weight loss, but whether the weight loss is maintained is unclear.
  • A keto diet is highly restrictive, which makes it unsustainable in the long term. It can also lead to nutrient deficiencies and unpleasant symptoms.
  • The keto diet was created for children with epilepsy and can be successful in reducing seizures.
  • A keto diet can mean you’re less likely to eat ultra-processed foods. It could also help with blood cholesterol levels.


I hope you enjoyed this blog post; I’d love to hear your thoughts in the comments below.

Bye for now! 👋



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