Why am I not losing weight on keto? Your keto questions answered.

What is the keto diet?

In a nutshell, the keto diet is a low carbohydrate, moderate protein and high fat diet. It was originally developed in 1921 by a man named Dr Russel Wilder. He used the diet to try to reduce epileptic fits in children.(1)

Indeed, the Epilepsy Society still recommends it in specific circumstances, where seizures can’t be controlled by anti-epileptic drugs.(2)

Some athletes also use tweaked versions of the keto diet to help with their performance.

However, most of us will know the keto diet as a weight-loss tool. In recent years, it has surged in popularity as an easier way to lose weight quickly.

In this article we’ll be looking at this type of keto diet, rather than one which is prescribed by medical professionals to treat disease.

What is ketosis?

The keto diet works by putting your body into a state known as ‘ketosis’.

When you eat a normal diet including carbohydrates, your body’s main source of energy is glucose.

However, if you drastically reduce the amount of carbohydrates you eat, your body has to look elsewhere for the energy it needs.

Instead of using glucose, your body starts to use ‘ketone bodies’ as your primary source of energy. These are made when fats are broken down.(3)

This state of ketosis is thought to be quite safe, and your heart, brain and muscles can all use ketone bodies as an energy source. In fact, they are actually a more efficient source of energy than glucose, as gram for gram they can produce more ATP.(3) (Adenosine triphosphate, or ATP, is the ‘energy molecule’ of the body. For more on ATP and how your body makes and uses energy, check out our article on healthy energy foods.)

What is the appeal of the keto diet?

Transferring your body’s source of energy from glucose to ketone bodies essentially means that your body will burn fat to power your normal activities.

This has several advantages in terms of weight loss.

Firstly, you can lose weight very quickly. Some estimates suggest you could lose up to 10lb in two weeks.(3) However, it’s likely that some of this initial weight loss is water, before you then begin to lose fat.

Unlike most other diets, you don’t need to restrict the number of calories you’re eating on the keto diet. There is no restriction on your intake of fats.

Eventually, you may even experience a decrease in appetite which helps with further weight loss.(3)

As such, the keto diet can be quite an effective way to lose weight quickly.

In addition to this, scientists are investigating whether it could help with medical issues such as dementia, brain trauma, metabolic disorders and acne.(3)

What are the downsides?

The keto diet remains quite controversial among scientists and nutritionists. While it can help people to lose weight, there are also some risks to consider.

Firstly, many people find it difficult to stick to, as it requires a substantial change from most normal eating patterns. Low compliance means that you’re unlikely to see the kind of weight loss described above, or could mean that you undo all your hard work after falling off the wagon!

Some of the benefits of this diet seem to disappear in the long term. For instance, weight loss, decreases in blood pressure and increases in ‘good’ HDL cholesterol may be present in the short term. However, by the 12 month mark, one study noted that the changes were no longer statistically significant.(3)

The keto diet may also be unsuitable for people with pre-existing health conditions. For example, while it may help people with diabetes, there is a risk that they may become hypoglycaemic during the early stages of the diet when carbohydrates are first removed. There are also risks for patients with other illnesses such as liver failure and pancreatitis, among others.(3)

There are also concerns around drastically increasing your intake of unhealthy fats - which is allowed under the keto diet. For instance, eating lots of saturated fat is linked with increasing your levels of ‘bad’ LDL cholesterol, and subsequent heart health issues.(4)

What is “keto flu”?

Even if you don’t suffer from a health condition, starting the keto diet can make you feel crummy.

Many people experience symptoms during their first transition into the diet. These have come to be known as “keto flu”.

Keto flu symptoms include nausea, vomiting, headaches, fatigue, dizziness and poor exercise performance.(1)

These symptoms tend to subside after a period of a few days to a couple of weeks. However, you might not find this period of feeling 'under the weather' acceptable.

How long should I be on keto?

The duration of your keto diet is really up to you, and how well you can stick to the diet over the long term.

You’ll need to follow it for a minimum of 2-3 weeks to see the effects, but you can continue it for up to a year. After this point, the safety of the diet becomes less clear.(3)

When undertaking this diet, your doctor may need to monitor its effects on your kidneys to make sure they are not damaged.(3)

Related reading

• What is reverse dieting?
• Prune health benefits: 5 reasons to add prunes to your diet