Six secret causes of low energy

24 May 2023

 Feeling short of get-up-and-go? Find out what could be triggering your low energy issues

We all get tired sometimes, but what if you can’t shake off that feeling of not having enough energy to get through the day – even after a good night’s sleep?

One in five people spend their days feeling unusually tired and one in 10 have long-term low energy, according to the Royal College of Psychiatrists.1 If you’re always tired or feeling exhausted, a number of things could be triggering your lack of energy, but some of them may surprise you…

1. Eating too much sugar

Eating a diet rich in simple carbohydrates, like cake and biscuits, can lead to feelings of low energy and fatigue. This is because refined starches and sugars cause spikes in blood glucose levels, and as they plummet back down, you experience fatigue.2,3 A 2015 study published in the journal Obesity found that teenagers given a high-sugar, low-fibre breakfast experienced fluctuating blood glucose levels, giving them less energy – they were later more likely to turn down sport in favour of a sitting-down activity.4

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2. Not eating enough vital vitamins

Certain vitamins and minerals are important when it comes to getting the most energy out of the food we eat. Magnesium and phosphorus – found in tofu, beans and wholegrains – are two of the nutrients that help break down our food into fuel.5,6,7 Meanwhile, iron is essential to make haemoglobin, which carries oxygen around the body to the cells: our cells need oxygen to break down glucose into energy. Iron deficiency also triggers anaemia, which makes you feel extremely tired.8,9, Iron is in dark green leafy vegetables, egg yolk and sesame seeds.10

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3. Portion distortion – eating large meals

If you’re suffering from low energy, avoid eating three large meals a day with long gaps in between. Health experts believe our brains have only small stores of energy and need a regular supply of nutrients to feel refreshed, so try eating a small meal every few hours.11 Watch out for heavy lunches in particular. They cause a spike in blood sugar, and what goes up must come down… usually in the form of an afternoon energy slump.12

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4. Overdoing the alcohol

Daytime drinking may make you feel drowsy and lethargic.13 And boozing before bedtime risks disturbed sleep: alcohol increases the levels of the stress hormone epinephrine, raising your heart rate and making you more likely to wake in the middle of the night. In fact, drinking causes 10% of cases of persistent insomnia – something that can definitely reduce your energy levels.14 Try cutting back by alternating every alcoholic drink with a soft drink, or going alcohol-free for a number of days a week.15

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5. Suffering from stress

A 2011 study, published in BMC Research Notes, found that people experiencing the most stress reported greater levels of fatigue.16 This is because stress lowers your immune system, raises your blood pressure and breathing rate, slows the digestive system and heightens alertness – all of which can make getting a good night’s sleep that much trickier.17,18 Make time to relax every day – even just 15 minutes. This will help lower your blood pressure and heart rate, and calm the stress response.19 Try meditation, yoga or deep breathing exercises.20

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6. You’ve got a medical condition

Certain conditions and diseases can trigger feelings of low energy. These include:21,22
  • chronic fatigue syndrome
  • fibromyalgia
  • depression
  • diabetes
  • underactive thyroid
  • kidney infection
  • coeliac disease
  • anaemia

If you are suffering from unexplained low energy levels, you must see your GP to check whether you are suffering from any of these, or other, conditions.

Advice is for information only and should not replace medical care. Please check with your GP before trying any remedies.
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  1. . Royal College of Psychiatrists. Tiredness. Available from:
  2. . Kiecolt-Glaser JK. Stress, Food and Inflammation: Psychoneuroimmunology and Nutrition at the Cutting Edge. Available from:
  3. . Harvard Health Publishing. Eating to boost energy. Available from:
  4. . O’Reilly GA, et al. Effects of high sugar and high fiber meals on physical activity behaviours in Latino and African American adolescents. Available from:
  5. . Huskisson E, Maggini S and Ruf M. The Role of Vitamins and Minerals in Energy Metabolism and Well-Being. Available from:
  6. . Dietitians of Canada. Food Sources of Phosphorus. Available from:
  7. . Dietitians of Canada. Food Sources of Magnesium. Available from:
  8. . BBC Bitesize. Life processes. Available from:
  9. . Medical News Today. What to know about iron deficiency anaemia. Available from:
  10. . Dietitians of Canada. Food Sources of Iron. Available from:
  11. . As Source 3
  12. . As Source 3
  13. . Harvard Health Publishing. Alcohol and fatigue. Available from:
  14. . As above
  15. . Drinkaware. Reasons for cutting down on alcohol. Available from:
  16. . Kocalevent RD, et al. Determinants of fatigue and stress. Available from:
  17. . Greenberg DB. Clinical Dimensions of Fatigue. Available from:
  18. . Medical News Today. Why stress happens and how to manage it. Available from:
  19. . Harvard Medical School. Best ways to manage stress. Available from:
  20. . As above
  21. . As Source 17
  22. . NHS Choices. 10 medical reasons for feeling tired. Available from:

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