Keto has been all the rage in certain circles for years now, with fans of the diet claiming it is some kind of miracle cure-all for your dietary woes – and whatever else that ails you.

I’ve heard all sorts of claims, ranging from fat loss to cancer cures, to thicker hair, improves acne, improves brain function.

Most of these are not true.

In fact, there aren’t too many instances where keto diets are the best option. But I will come to those shortly.

Firstly, what even is the ketogenic diet?

A keto diet is where where carbohydrate intake is so low, your body starts producing something known as ketone bodies. For most people this is under 50g a day, but for some it could be as low as under 20g.

The ketone bodies are a breakdown product of fat and are used to fuel cells that normally depend on glucose.

Most people turn to keto diets as a way to lose weight, under the impression that eating keto will adapt their body to “burn more fat”.

And yes, you will burn more fat, because you’re eating more fat – and the food you eat is the fuel your body uses to move. But unless you’re in a calorie deficit, you won’t be burning body fat, just the dietary fat you’ve been eating.

Burning body fat always comes down to energy balance. If you’re in a caloric deficit, your body will use fat stores for energy. And if you’re not, it won’t.

As a diet method, it’s incredibly restrictive and not any better than any other method.

The research shows there’s no difference between low carb and low fat diets in terms of weight loss when calories are matched – so it just comes down to what you can adhere to and what you actually enjoy.

Some people really love keto. Some people don’t.

The reason most people who do lose weight with keto lose weight, is because they’ve stopped eating all of their favourite foods and ended up in a calorie deficit.

Many people find high fat diets quite satiating, which means it’s easier to eat less as they’re not hungry. Some people don’t.

As a method of weight loss I wouldn’t recommend it. It’s really hard and will make your life hard and make it difficult to socialise. It will probably also give you bad breath – also known as keto breath. This is you exhaling something called acetone, caused by the elevated ketone levels.

This acetone breath is an indicator that you’re in ketosis, the goal of a keto diet. Because it’s so hard to consistently eat few enough carbs a day, a lot of people who think they’re doing a keto diet are actually just doing a low carb diet.

Keto and health

Outside of weight loss, the main condition that has been studied is epilepsy. This dates back to the 1920s as a way to alleviate seizure symptoms in people with hard to treat epilepsy.

Current research shows it may be helpful in epileptic children for whom medication hasn’t worked. But it also comes with a variety of side effects, from gallstones to vomiting.

Keto has also been shown to reduce fasting blood glucose independently of weight loss. This could be beneficial in managing diabetes.

But in both of these instances it’s important to talk to your doctor and not just start doing keto to see if it helps. It might not. And this page is certainly not a place to be getting medical advice, so consult your doctor.

Keto and training

On the training-front, it currently looks like power output might be affected, with people on keto diets performing less well in the gym and most sports.

One study found absolute VO2 Max declined slightly after six weeks of a keto diet.

Although, while most athletes’ performance will be hampered by keto, there’s a theory that ultra runners and other endurance athletes might actually get either a neutral or a positive effect from keto diets.

So this means any strength athletes or sprinters would be worse off if they adopted a keto diet, and ironmen and ultra-marathoners might be ok or even better.

That’s a small slice of people though.

If you’d like to share your thoughts on keto, feel free to find me on Twitter (@superpennie) or Instagram (@superpennie).

I’ll be covering another diet next week, so if you have a request, let me know!

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