5 ways the keto diet affects your energy levels

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Qualified Nutritionist (BSc, MSc, RNutr)
@emmatalkshealth
@EmmaThornton
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06 December 2019

What is the keto diet?

The keto diet (also known as the ketogenic diet) is a low carb, high fat diet that is becoming increasingly popular. Eating this way puts the body into ketosis, a metabolic state in which fat provides most of the fuel for the body. There are several benefits associated with the keto diet such as weight loss and reduced blood sugar levels. However, there are also a few less positive implications of this diet, including low energy.

There are several ways the keto diet can affect your energy levels including:

  • Keto flu
  • Lack of serotonin
  • Effects on hormone levels
  • Lack of dietary fibre
  • Low bile concentration.

1. Keto flu

When you start the keto diet, you may experience symptoms of the keto flu. This occurs as a result of your body adapting to the lack of carbohydrates.

During this change, the body stops burning sugar for energy and instead starts burning fat. When fat is broken down it produces ketones, which are then removed by the body through frequent urination. This can lead to dehydration, as well as flulike symptoms such as fatigue, headaches and nausea. These can last for a few days and, in some cases, up to a week depending on how long it takes your body to adapt to the dietary changes.

Symptoms can be managed by:

  • Staying hydrated – Drink 1.5 litres of still, plain water daily. Staying hydrated may help relieve symptoms of fatigue.
  • Getting enough sleep – Fatigue and struggling to get to sleep are both common symptoms of keto flu. If you get enough sleep at night this may ease these symptoms.

2. Lack of serotonin

Serotonin is a neurotransmitter that controls the sleep and waking cycle, and helps to keep us happy and energised. Low serotonin levels can result in poor sleep and low mood.

Serotonin levels can be maintained through diet by including foods containing tryptophan. Food sources of tryptophan mainly include protein sources like poultry. Your body converts tryptophan into serotonin, whilst carbohydrates stimulate insulin production, which helps tryptophan reach the brain. Therefore, if you mix foods that contain tryptophan and carbohydrates together this may boost your serotonin levels.

However, since the keto diet contains very few carbs, you could end up having low serotonin levels and this could make more of a struggle to get to sleep. Research has shown that low carbohydrate intake can lead to difficulty maintaining sleep too.1

3.Carbohydrates and hormones

The thyroid gland produces two hormones: triiodothyronine (T3) and thyroxine (T4). Both of these hormones ensure that all of the cells in your body work effectively – they play a key role in the development of the brain and can have an impact on your mood. Diet, however, can alter thyroid hormone levels.

Low carbohydrate intake can cause a decrease in T3 levels, but low T3 levels may also indicate hypothyroidism (underactive thyroid). Symptoms of hypothyroidism often include tiredness and weakness, which is backed up by a study that found a direct link between fatigue and lack of T3 production.2

Carbohydrates help to control the release of cortisol (a stress hormone). Low carbohydrate intake may lead to higher cortisol levels. Increased cortisol levels have been associated with sleep disturbances, which could lead to tiredness. As well as this, high cortisol levels are also associated with stress. As I mentioned in my last blog, there is a vicious circle between stress and poor sleep. So, this could be another reason why the keto diet can lead to low energy.

Furthermore, high cortisol levels are associated with an increase in progesterone production. Progesterone has a complimentary relationship with the thyroid as it helps to ensure the effective production of thyroid hormones, as well as helping to increase thyroid hormone levels in the blood. If your progesterone levels are "out of sync" this could also lead to low energy.


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4. Lack of dietary fibre

It is common for people on the keto diet to be lacking in dietary fibre (a type of carbohydrate that helps the function of the digestive system). Fibre-rich foods such as starchy vegetables (sweet potatoes and corn) and wholegrain products are often avoided in the keto diet. However, fibre is essential in the diet since it adds bulk to stools, making them softer and easier to pass, therefore helping to avoid constipation. As well as affecting your gut, lack of fibre can also affect your energy.

Firstly, fatigue and constipation often go hand in hand. When you are constipated, your colon holds on to waste products, resulting in your body being unable to fully absorb nutrients. Malabsorption of nutrients can then exacerbate digestive problems such as constipation and diarrhoea, as well as contributing to fatigue.

This is backed up by a study that found that there is a direct link between constipation and malnutrition.3 So, if you're following the keto diet it is important to drink plenty of water (1.5 litres daily!) and add some fibre-rich keto foods to the diet. Good sources of fibre-rich foods suitable for the keto diet include raspberries and cauliflower.

Secondly, a diet low in fibre has been linked to poor sleep. Research has found that a diet high in fibre is associated with restorative sleep (the completion of all of the sleep stages).4 Therefore, this suggests that consuming a diet low in fibre may prevent restorative sleep, resulting in poor sleep and tiredness. If you're following the keto diet, consider adding walnuts to your diet. These are a good source of dietary fibre and tryptophan, which may help you to get a good sleep.

Finally, eating a diet low in fibre is also associated with diverticulitis (inflammation of the small pouches along the wall of the colon). Symptoms of diverticulitis tend to include painful digestive symptoms, as well as lack of energy.5 If you're thinking of following the keto diet, ensure that you are getting enough dietary fibre to avoid diverticulitis. Consider including walnuts and chia seeds in the keto diet as these are both good sources of dietary fibre.

5. Low bile concentration

Bile is produced in the liver and stored in the gallbladder. Bile aids digestion by helping to break down and absorb fats, as well as assisting in getting rid of waste products. However, some people do not have a high enough concentration of bile to break down the higher amounts of fat that are consumed in the keto diet. If fat can't be absorbed it passes into the colon, where it can act as an irritant and possibly lead to diarrhoea. Fatigue can then be a side effect of diarrhoea.

If you're following the keto diet and find that you are suffering from diarrhoea, make sure that you drink plenty of water to avoid dehydration. Also, you may want to consider liver supporting remedies. Check out our blog 'How to detox your liver' for more information on remedies to support your liver.

So what can you take away from this blog?

The keto diet may be beneficial for weight loss, however, it has also been linked to low energy levels. If you wish to follow the keto diet make sure that you stay hydrated and ensure that you're getting all of your important nutrients to avoid fatigue.

References

  1. https://www.ncbi.nlm.nih.gov/pubmed/23419282/
  2. https://www.meassociation.org.uk/2018/03/frontiers-press-release-chronic-fatigue-syndrome-possibly-explained-by-lower-levels-of-key-thyroid-hormones-20-march-2018/
  3. https://www.tandfonline.com/doi/abs/10.1080/00365521.2018.1473485?journalCode=igas20
  4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4702189/
  5. https://www.nidirect.gov.uk/conditions/diverticular-disease-and-diverticulitis

What you said

We recently ran a poll to find out if you've ever tried the keto diet. We've crunched the numbers and here are the results.

Results: Have you ever tried the keto diet?

The keto diet is becoming increasingly popular, so it's no wonder that 47.6% of you want to try the keto diet.

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