You want to get fit for the summer and lose weight so you head for the gym.

Once you get there, you are tempted by a dazzling display of "sports" drinks.

Athletic and energetic images spring instantly to mind. Think Linford Christie and Daley Thompson.

Think "Lucozade for the human race". Or perhaps, think again and look at the ingredients.

Chemical cocktails like Lucozade are packed with "carbohydrate blends" of glucose syrup and maltodextrin (another name for sugar) as well as the artificial sweeteners aspartame and acesulfame K.

Such highly-sugared drinks are not necessary during brief periods of exercise and may actually be detrimental to our health and physical performance.

A concentrated intake of refined sugar provides a short energy burst but the long-term effect is to destabilise blood sugar and blunt the production of growth hormone and testosterone which are so important for developing muscles.

These drinks also contain artificial flavourings and preservatives like sodium benzoate and potassium sorbate implicated in hyperactivity, asthma, urticaria and insomnia. Not exactly the ideal scenario for a budding Olympian.

The ultimate sports nutrient is water and losing fluid during exercise results in decreased performance.

If you are only three per cent dehydrated, you lose ten per cent of strength and eight per cent speed.

Small amounts of water should therefore be replaced on a regular basis during exercise. You don't need the extra sugar to make it taste better.

It's less well known that we need the right kind of fats to increase the rate of energy, stamina, performance and recovery.

I spoke to Oscar Umahro Cadogan, a nutritional and fitness consultant to some of Europe's top national athletes, and he explained how essential fatty acids enhance any sporting performance.

Sources of essential fatty acids come from seeds, fish and their oils.

You can buy specially-formulated oil blends from healthfood stores (Udo's Choice, Essential Balance).

As they spoil easily, make sure you don't expose them to heat, light or oxygen.

They are also know as "super fats" and help us keep slim by increasing the rate at which we burn calories, making us feel more energetic and physically active.

They are anti-catabolic, preventing muscle breakdown and increasing lean muscle mass by turning down the body's own production of fat.

They also lower appetite and cravings for sugar, junk food and the damaging processed and fried fats.

All this leads to lower calorie intake.

In a recent trial with 70 Danish athletes, it was even found that two to four tablespoons of an oil blend per day significantly improved cholesterol and triglyceride levels.

Essential fatty acids are important for optimum energy production as they help to transport oxygen into cells.

Because of their integral part in the structure of cell membranes, they prevent unwanted dehydration.

Increased membrane fluidity also means better nutrient utilisation.

This is particularly important for improving immunity and preventing infections athletes are so prone to.

Essential fats have potent anti-inflammatory properties, reducing joint, tendon and ligament strains and improving recovery rates after intensive training.

It appears these "fitness fats" makes us healthier and anything that makes us healthier improves our strength, endurance and rate of recovery - in short our ability to perform, whether your goal is to walk around the block or run 10,000 metres.

Martina is a qualified nutritional therapist at the Dolphin House Clinic and Crescent Clinic of Complementary Medicine, Brighton, or visit www.thehealthbank.co.uk