The real reason you are tired all the time

One of the biggest complaints that my patients mention is fatigue. No matter how common it is, unexplained mental or physical fatigue is not normal or healthy. It’s a sign that something is not right.


There are many factors that are hidden behind fatigue, and the good news is that many of these things are easily addressed and reversed. Bonus: many of these dietary and lifestyle changes improve your overall health and immune system and prevent any chronic disease.

Causes of fatigue

Let’s take a look at the obvious and not so obvious underlying causes of fatigue.

Sleep Issues

Poor sleep. Poor sleep (like light sleep, sleeping late, insomnia, intermittent sleep, sleeping with a partner that has poor sleep) leads to poor cell regeneration and restoration. No wonder why you wake up unrefreshed.

Sleep timing. Going to bed late means less time for cell recycling and DNA damage repair.

Circadian rhythm. Our bodies have something called a ‘circadian’ rhythm that helps us to be sleepy at night when it’s dark and wakeful during daylight. Things like screens, bright lights, working late, shift work, wifi, stimulators, heavy eating, alcohol, medications, lack of exercise and so on can all disrupt the circadian rhythm and raise stress hormones. All the above can be addressed with lifestyle changes and the correct supplements. For example, melatonin may help you sleep earlier but will not prolong sleep in all.

Hormones. Hormones can have a huge effect on sleep quality. For women in perimenopause and women with hormonal imbalances (like in PCOS and PMS) can get anxiety, agitation, and light sleep, due to low progesterone levels. This is true for men and testosterone too. Herbs and creams can help balance the hormones and hence restore sleep quality.

Thyroid Dysfunction

Thyroid disease is more common than many of us think. Many people have hypo-clinical hypothyroidism, which makes it very difficult to realise and test for. The thyroid is responsible for energy production. Low thyroid hormone production can result in extreme fatigue.

A thyroid disorder can manifest with many different symptoms including low basal body temperature, fatigue, weight gain, dry skin, constipation, hormonal issues, insomnia, skin issues, dull hair and so on.

Hyperthyroidism can as well interrupt sleep by increasing heart rate and resulting in fatigue.

Everyone can benefit from supporting the thyroid, which is the key to optimal function and energy. Not often do I see full thyroid panels in blood work. Ask your GP for one. An undiagnosed thyroid condition is extremely common.

Nutrients like selenium, zinc, vitamin A, fish oils, guggul, ashwagandha, B vitamins and so on are essential for optimal thyroid function and energy production. Avoiding gluten, soy, and dairy can also help an over or under-active thyroid gland. However, you should ask your nutritionist for a specific and personalised diet.


While you may not have drawn a link between what you eat and your energy levels until now, I have to tell you that diet plays a huge role in fatigue, as well as sleep quality, energy production, mood. 

Sugar and carbohydrates. You’ve probably all heard that a lunch full of carbohydrates makes you sleepy. This is actually true. A diet high in sugar and refined grains (sweets, pastries, processed/packaged foods, morning cereals and granolas, fruit juices, pasta, pizza, white rice, and even high consumption of complex carbs) lead to a sudden increase in blood sugar and insulin, followed by a sudden decrease (crash and tiredness). Stable blood sugar levels ensure stable energy levels. 

Switching to a diet of healthy carbohydrates like fresh vegetables and small amounts of fruit, you will immediately feel a lot more energised. Adequate amounts of healthy fats and quality protein help balance blood sugar and lead to more sustained energy.

A diet high in carbs and sugar, moreover, depletes certain vitamins and minerals, especially B-vitamins and magnesium that are needed by the energy-yielding cycle in mitochondria.

Food and chemical sensitivities/intolerances

Chronic stress, atopic conditions, alcohol, smoking, sugar consumption, medications and especially antibiotics, NSAIDs and the contraceptive pill can all alter gut integrity leading to food sensitivities. Apart from digestive problems and rashes, food sensitivities can manifest as low energy levels.

Foods that are eaten on a daily basis are most often the ones to blame. The most common foods that cause reactions are gluten, wheat, dairy (casein, lactose), soy, yeast (baked goods, bread) and corn. That’s not a comprehensive list but this is a good place to start looking.

A nutritionist can help you safely do an elimination diet by ensuring good nutrient intake, followed by a re-introduction phase. Food intolerances and sensitivities, do not lead to immediate symptoms, like allergies, they can actually show up in a few hours and up to 72 hours after consuming them.

A leaky gut can also lead to chemical and environmental sensitivities (mould, dust mites, animals, seasonal allergies, pollen, chemicals like detergents, perfumes, dyes and so on).

Inadequate protein consumption

Carbohydrates are much easier to find and consume - sandwiches, crisps, fruit salads, baked goods, porridge, chocolate are everywhere, especially when you are looking for a quick lunch or a snack. Protein usually needs some kind of preparation and planning (meat, fish, seafood, eggs, pulses, beans, nuts, seeds, dairy), so many western diets lack sufficient protein. 

Vegan and vegetarian diets often lack protein too. Beans, quinoa, mushrooms and nuts don’t provide as much protein as animal sources and are not as bioavailable. Moreover, consuming legumes on a daily basis can be harsh on the digestive system. Make sure you speak with a professional to design a personalised dietary plan for your needs. 

Inadequate protein and hence muscle loss, as well as insufficient iron, vitamin A, omega 3 and vitamin B12 levels can lead to extreme fatigue. Protein is also essential to help produce enzymes that activate metabolism.

Folate, B12, B6, iron and copper anaemia can lead to tiredness and lethargy. A diet low in protein and high in carbs leads to hyperinsulinaemia with consequent exhaustion. 

Best sources of protein include grass-fed meat, pasture-raised eggs, wild-caught oily fish, soaked nuts and seeds, goat and sheep dairy, sprouted legumes. Protein powders can be beneficial as long as they are quality ones, and suggested by a certified practitioner.


Once you are thirsty, you are already dehydrated! Each of us should drink one litre of water for each 22kg of body weight. Herbal teas, as well as smoothies, coconut water and vegetable juices count towards daily hydration. However, soft drinks, coffee and alcohol don’t! The above block the anti-diuretic hormone, making you lose water. You should drink one glass of water for every cup of coffee/tea and one to two glasses of water for each alcoholic drink, in order to stay hydrated.

Lack of essential minerals and electrolytes can lead to insufficient cell hydration. No matter how much water you drink, if you lack micronutrients it won’t reach intracellularly. Adding a little Himalayan or unrefined sea salt to your morning water can make you feel more robust and hydrated, as fluids will be more easily absorbed. Dehydration leads to drowsiness and brain fog!

Underlying health conditions

In addition to the above, the following conditions (diagnosed or undiagnosed) can lead to low energy levels: 

  • adrenal fatigue
  • type 1 and 2 diabetes
  • heart disease
  • hormonal issues (stress, PCOS, PMS, menopause, andropause, thyroid etc)
  • depression and/or anxiety
  • fibromyalgia
  • chronic fatigue syndrome
  • chronic viral or bacterial infection
  • seasonal allergies

A health professional may want to order extra lab work, functional testing, check your diet diary and look over any medications and supplements you are taking.

Nutrient deficiencies

Nutrient deficiencies are probably the most important factor of fatigue. There are many nutrients that can contribute to fatigue, with the most common being vitamin D (we have vitamin D receptor on all our cells; optimal levels: 45+ ng/mL all year round!), iron (anaemia-related fatigue, helps to carry oxygen around the body), B-complex vitamins (anaemia and energy-yielding mitochondria cycle), magnesium (needed by more than 300 chemical reactions) and antioxidants (oxidative stress; especially glutathione and coenzyme Q10). Low nutrient status can arise from low intake and/or low assimilation, due to inadequate digestive enzyme secretion from the digestive tract. A health professional will help you identify which nutrients you are missing and why.

A cheap multivitamin or one bought from supermarkets or a high-street store is less likely to provide nutrients in their bioavailable form for absorption and use. For example, B vitamins that do not come in methylated forms are rarely absorbed. Vitamin D comes almost solely from the sun. During the winter months, it is almost impossible to reach optimal levels without supplementation. Self-supplementation is not suggested as can lead to cofactor imbalances, like calcium. About two-thirds of the population lacks magnesium. Magnesium deficiency leads to insomnia, tiredness, constipation, headaches, cramps and anxiety. Antioxidants prevent oxidation and fatigue. Your nutritionist will inform you about the best sources of nutritional antioxidants (like wild berries and organ meats) and will let you know if you need supplemental antioxidant nutrients.

The views expressed in this article are those of the author. All articles published on Nutritionist Resource are reviewed by our editorial team.

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