Why Do You Feel Tired All the Time? Common Nutritional Causes of Fatigue
- Carla
- 1 day ago
- 3 min read
Feeling tired all the time can be deeply frustrating, especially when you sleep but still wake drained. Many women describe it as feeling foggy, flat or constantly running on empty. Fatigue can have many causes, including medical conditions, sleep, stress, medication and thyroid changes, but nutrition is often relevant.
In functional nutrition, tiredness is information. Your body may be asking for steadier blood sugar, better nourishment, nutrient support or a gentler pace.
When Feeling Tired All the Time Needs Attention
Occasional tiredness is normal after a busy week, poor sleep or illness. Feeling tired all the time is different. NICE describes tiredness and fatigue in adults as a common, non-specific symptom in primary care, with many possible explanations.
Speak to your GP if tiredness is new, severe, worsening or affecting daily life. Seek medical advice if feeling tired all the time comes with unexplained weight loss, heavy periods, shortness of breath, chest pain, dizziness, blood in your stool, night sweats, fever, low mood, or a sudden change in health.
1. Blood Sugar Dips and Skipped Meals
One common nutritional cause of feeling tired all the time is unstable blood sugar. This can happen when breakfast is skipped, meals are low in protein, or the day is built around caffeine, snacks and quick carbohydrates.
You might notice feeling shaky, irritable, anxious, lightheaded, hungry, sweaty, weak or suddenly desperate for something sweet. NHS guidance notes that low blood sugar can include hunger, dizziness, anxiety, sweating, shaking and feeling tired or weak.
A more balanced meal includes protein, fibre rich carbohydrates, healthy fats and colour. Try Greek yoghurt with berries and seeds, lentil soup with olive oil, or salmon with sweet potato and greens.
You may also enjoy reading:Blood Sugar Imbalance: Why It Affects More Than Just Your Energy Levels
2. Low Iron, B12 or Folate
Iron, vitamin B12 and folate support healthy red blood cells and oxygen transport. When these nutrients are low, fatigue can feel physical and persistent. You may also notice breathlessness, headaches, dizziness, low mood, poor concentration, pins and needles, mouth ulcers or a sore tongue.
The NHS lists extreme tiredness and low energy among symptoms of vitamin B12 or folate deficiency anaemia. NICE also includes cognitive changes, breathlessness and headache among possible signs. Iron deficiency is particularly relevant for women with heavy periods, pregnancy history, restrictive diets, digestive issues or poor absorption.
The British Dietetic Association highlights meat, fish and poultry as sources of well-absorbed iron. Plant-based iron can be found in beans, lentils, tofu, nuts, seeds, leafy greens and fortified foods. Pairing plant iron with vitamin C rich foods can help absorption.
Please do not self-prescribe high dose iron. Check levels with your GP or qualified practitioner.
3. Vitamin D and Low Winter Light
In the United Kingdom, low vitamin D is common because sunlight exposure is limited for much of the year. The NHS advises that everyone should consider a daily vitamin D supplement during autumn and winter. Low vitamin D is best known for bone and muscle health, but some people also report tiredness, aches or low resilience when levels are poor.
Food sources include oily fish, eggs and fortified foods. If you feel tired all the time, especially with muscle aches or low mood, ask your GP whether testing is appropriate.
4. Not Eating Enough
Feeling tired all the time can also come from under eating. This is common in women who have spent years dieting, skipping meals, cutting carbohydrates, avoiding fats or trying to be “good” with food. Your body needs enough energy to run your brain, muscles, hormones, digestion and nervous system.
Signs that you may need more nourishment include feeling cold, waking at night, low mood, cravings, constipation, hair shedding, poor exercise recovery and needing caffeine to function.
5. Dehydration and Mineral Balance
Even mild dehydration can make you feel tired, weak, dizzy or headachy. NHS dehydration guidance lists tiredness, thirst, dark urine, dry mouth, headache and light-headedness as possible signs. If you rely on coffee, forget to drink water, sweat often, or have digestive symptoms, hydration may need attention.
Try water on waking, herbal teas, soups, broths and hydrating foods like cucumber, citrus, berries and leafy greens.
A Gentle Way Forward
If you feel tired all the time, begin with the foundations. Eat breakfast with protein, build balanced meals, hydrate consistently, include iron and B vitamin rich foods, prioritise sleep, and avoid pushing through every signal with caffeine.
At The Heart of the Matter Nutrition, I work with clients across the United Kingdom who want to understand why fatigue keeps returning. Through nutrition, we look at food patterns, symptoms, digestion, hormones, blood sugar, stress and lifestyle so your plan feels realistic and supportive.
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