You don't need a PhD in biochemistry to know that food contains calories and calories provide our bodies with energy - but not just any food will do. Here we show you how just a few simple tweaks to your daily eating habits can more than double your energy in just 5 days!

1. Get Active
Getting active may be the last thing you feel like doing when you're tired and rung out but the phrase ‛energy makes energy' really is true. This is because, the fitter your are the more efficient your heart and lungs will be at getting oxygen into and around your body - and the more oxygen you can take in and utilise the more energy you can create so aim to do some form of cardiovascular exercise whether it's cycling, dancing, swimming, running or walking for at least 30 minutes five times a week.

2. Eat at Least Two Low GI Meals a Day
Many of the carbohydrate based foods that we eat on a daily basis such as breads, pasta, rice, cereals, cakes and biscuits are highly processed, refined and lacking in their natural fibre therefore, once eaten, they are broken down very quickly causing our blood sugars to surge. These surges are followed by a sudden drop leaving us feeling tired, lethargic and lacking in concentration.

Research shows that swapping many of these fast releasing, high GI, foods for lower GI alternatives such as wholegrain cereals, rye bread, wild or basmati rice, beans, pulses and fresh fruit and vegetables is an excellent way to significantly increase your energy because not only are they far richer in essential energy giving vitamins and minerals but they also provide a far slower, steadier and more constant release of energy throughout the day.

3. Cut Back on Fatty Foods
Gram for gram, fat contains more than double the amount of energy provided by protein or carbohydrates. Therefore, it may seem logical that a high fat diet should actual increase our energy levels. However, research shows the reverse to be true. This is because a diet rich in fat inhibits the body's natural ability to burn oxygen and therefore results in us feeling sluggish and lethargic.

4. Graze Don't Gorge
Distribute your calories equally among breakfast, lunch, and dinner. A skimpy breakfast, a hurried lunch, and a huge evening feast are about the least energy-efficient eating schedule imaginable. Instead, try adding a mid-morning and mid-afternoon snack to your daily meal schedule and keep calorie intakes in check by downsizing your other three meals. This mini-meal plan is a great way to boost energy levels because it provides your body with energy as and when it needs it and prevents long time lags between meals which may lead to over or under eating.

5. Get plenty of Vitamin C and Iron
Vitamin C helps to produce carnitine, a molecule that helps your body burn fat for energy. Low intakes of vitamin C result in lower levels of carnitine and ultimately a decreased ability to create energy from your fat stores.

Vitamin C is also essential in ensuring the body is able to absorb iron. Approximately 40% of women in Britain have an inadequate intake of iron and if you are one of them you may find yourself barely able to lift one foot in front of the other, feeling permanently lethargic, grumpy, lacking in motivation and concentration. Eating more iron-rich foods is one of the most significant energy-boosting moves you can make because iron is essential in transporting oxygen via red blood cells to wherever it's needed in the body and without oxygen it's impossible to create energy.

To maximise your ability to absorb iron from foods it's a good idea to eat foods rich in Vitamin C and Iron within the same meal such as a glass of fresh orange juice with your iron fortified breakfast cereal or adding tinned tomatoes to beef mince when making chilli or bolognaise.

6. Drink at least 2 litres of water everyday.
Tea, coffee and alcohol will not only impair your body's ability to sleep and absorb essential energy producing vitamins and minerals but they will dehydrate you too. Dehydration results in reduced blood volume which ultimately means your ability to transport all the essential ingredients for energy such as blood sugars (glucose), iron, and oxygen around your body is greatly reduced leaving you feeling tired, heavy and apathetic.

For more Diet and Fitness tips from our Expert, Rachael-Anne Hill, click here