Eating For Energy
Metabolism & Food Energy
We all have days when feel like we could run a marathon, and others when we struggle to throw back the duvet. Energy is a wonderful thing when you have it. But when you’re running on empty it can make even the simplest things challenging. That’s because we need energy from the food we eat to do absolutely everything, from blinking to thinking.
The actions that take place in your body that change food into energy are collectively known as your metabolism. Metabolism involves literally thousands of chemical processes, but here’s how it works in a nutshell:
- After you eat your digestive system releases acids and enzymes to break your food down into smaller components.
- Proteins are broken down into amino acids, fats into fatty acids and carbs into simple sugars such as glucose. All of these are absorbed into your bloodstream and transported to your cells.
- Processes within your cells extract the chemical energy from these components to make adenosine triphosphate (ATP), a molecule that can be used for all your cells’ energy needs. As well as being used for body functions, energy is stored in tissues such as your liver, muscles and fat for use later.
- Amino acids and fatty acids release energy, but carb sugars are the body’s main energy source (it will use carbs for energy first, and then fats and proteins when the sugars have been depleted; carbs also produce more ATP than fats or proteins).
- Certain hormones come into play including thyroxine (made by the thyroid gland), which controls how quickly or slowly metabolism happens. Insulin is produced by the pancreas to help your body use sugars for energy and to balance your blood sugar levels.
Did you know? The minimum amount of energy your body needs just to keep your essential body functions working is called your basal metabolic rate (BMR). This accounts for a fairly large portion of your daily calories – depending on your age and lifestyle it can be as much as 80 per cent, says the NHS.
What’s making you tired?
Food provides your body with the fuel it needs to make energy, which is one more argument for eating a balanced, nutritious diet. But some things can make your metabolism slow down and make you feel tired, whatever you eat.
Stress and a lack of sleep are two of the most obvious culprits, but tiredness can also be caused by drinking too much alcohol or being overweight or underweight. Some medical conditions can zap your energy too, including:
- Chronic fatigue syndrome (CFS) – or myalgic encephalomyelitis (ME) – causes extreme physical and mental fatigue along with other symptoms. Doctors still don’t know exactly what causes it.
- Hypothyroidism is the medical term for an underactive thyroid. If your thyroid isn’t up to scratch it won’t make enough thyroxine – an essential hormone for your metabolism.
- Anaemia makes you tired because when you don’t have enough iron in your blood. Eating more iron-rich foods such as meat, liver, nuts and beans can help fix this, or many use an iron supplement.
- Type 2 diabetes is becoming increasingly common in the UK with tiredness one of the main symptoms (others include being feeling thirsty all the time and peeing a lot).
- Hypoglycaemia – or low blood sugar – is when your blood glucose levels dip too low, making you feel drained, shaky and a bit woozy. Eating something that releases carbs slowly will make you feel better (try oats, wholegrain rice and pasta, beans, fruits and vegetables). And yes, having something sugary can make you feel better too, but it’s not the best option since you feel even worse once the sugar high has worn off.
Did you know? Depression is also a common cause of low energy and lethargy, particularly if it is associated with poor sleep or loss of appetite.
All foods give you energy your body can use. But some contain nutrients that can help boost your energy levels in other ways. Here are a few examples:
Nuts They may contain far more fat and protein than carbs, but nuts are also full of nutrients that help convert food energy into ATP, including magnesium, manganese, copper, calcium, zinc, biotin and vitamin B2. And while they’re high in calories most nuts have a low glycaemic index (GI), which means they release their energy slowly and steadily.
Seaweed It’s a good idea to make sure you’re getting enough iron in your diet if you want to avoid energy lows. Red meat is a good source but seaweed is an ideal veggie/vegan alternative (sushi, anyone?). Other plant-based iron-rich foods include green leafy veg, which also contains vitamin C to help your body absorb iron.
Beans and lentils Because they contain a balanced mix of protein and carbohydrate, beans and lentils are a decent source of sustained energy. The soluble fibre in beans and lentils also slows down the release of their sugars, while an amino acid called tyrosine produces brain chemicals that help keep you feeling alert. Other energy-boosting nutrients in beans and lentils include folate, manganese, zinc and iron.
Oats Having oats for breakfast gives you energy that lasts all morning. That’s because they contain a type of soluble fibre called beta glucans that helps keep your blood sugar levels stable, plus they’re full of metabolism-friendly vitamins and minerals, including iron, manganese and B vitamins.
Eggs Another way to start your day is to have an egg. The protein in eggs is rich in leucine, an amino acid that stimulates energy production. Eggs also contain B vitamins, plus the yolks are a good source of vitamin K2 (other K2 foods include dairy, liver, red meat, oily fish, sauerkraut and fermented soya beans called natto).
Berries Strawberries, blueberries, raspberries, blackberries, goji berries… Berries contain loads of vitamin C, a nutrient needed for numerous body functions, including helping it to absorb iron. Citrus fruit are also famous for having vitamin C (in fact vitamin C is found in most fruits and vegetables).
Did you know? The amount of energy in any particular food is measured in calories (or joules/kilojoules: one calorie = 4.2kJ). Different food groups contain different amounts of food energy:
- 100g of carbs or protein has around 120 cals (500 kJ)
- 100g of fat has around 717 cals (3000 kJ)
Stay healthy, stay energised
Undoubtedly the best (and longest-lasting) way to keep your energy levels up is to maintain a balanced and nutritious diet that supports your metabolism. Staying active helps too. But don’t overdo it, as working out too long and hard can leave you feeling drained rather than energized.
It’s also a good idea to keep your weight healthy, as carrying extra kilos can put a strain on your heart and make you feel exhausted. And while you’re at it, try reducing the stress in your life – or, at least, learn effective ways to deal with it like yoga, meditation or mindfulness.
If you do, you could have way more marathon days than duvet days.
But if you think you might need some extra help finding the energy you need, then find out which supplements might be able to help in: Energy Boost Supplements.