Health: Sports supplements are commonly part of a workout regime, but what do they contain?

NOT that long ago, sports nutrition might have meant nothing more complicated than a bottle of water and a banana after your workout. But walk into a health food shop today and you'll be bamboozled by body building shakes, foil-wrapped energy bars, thermogenic supplements and isotonic drinks.

All are aimed at improving your performance and helping you get in shape. But most of us would need a degree in food science to understand exactly what the ingredients are and what they do to our bodies. What was once strictly for hardcore weight lifters and elite athletes has started to enter the mainstream. But do any of these products work? And isn't a healthy, balanced diet enough any more?

Yes and no, says personal trainer Will Sturgeon. "You probably can't get enough protein in your regular diet if you are doing resistance training, so powders are ideal. There's nothing dodgy about them. They just give you a bit of help with your protein intake."

Dietary supplements, meanwhile, work by increasing the metabolism and suppressing the appetite so you lose weight faster. It's called thermogenic fat burning, and products such as USN's Xedra-Cut are taken by triathletes, boxers, rugby players and iron men and women.

TV Gladiator Enigma, Jenny Pacey, swears by them. "They are backed by scientific data," she says. "They give you the power to reach your optimum weight while still being able to lead a healthy lifestyle."

As for the rest of the nutritional maze, the demystification starts here.

www.willpowerpersonaltraining.co.uk

Xedra-Cut, 27.99 for 100 capsules, www.usn.co.uk

If you're still drinking water, you're so last century. These days, it seems, we're all going isotonic. "An isotonic drink is defined by having between 4g and 8g of carbohydrate per 100ml," explains Sturgeon. "This will give you energy plus hydration, so it's the best of both worlds."

However, you don't have to invest in expensive sports drinks to get the same effect. "If you mixed a fresh fruit juice half and half with water, that would bring it up to isotonic levels," he says. Alternatively, buy a powder. "It's the most efficient transportation and best quality of complex carbs. Put it in a glass of water and it's exactly what these sports drinks are made from, except they're sold for a fortune and are loaded with extra sugar."

It can be tempting to fuel up on a protein or carbohydrate bar when you get peckish, but don't be fooled into thinking they're the healthy option. Real food wins over processed every time.

"They're there primarily not as a meal replacement but as an assistance," says Sturgeon. "If you haven't eaten for a while, it'll give you some sustenance to keep you in a positive nitrogen balance - which means you have enough fuel in the body so it doesn't have to start eating its own muscle tissue. They serve a purpose," he adds - for instance, as a quick boost post-workout, "but they're not the most pure things to eat and many contain lots of additives."

They come in giant tubs and you can choose between anything from organic hemp and pea protein to egg, soy, milk or whey. So which do you choose?

"Always go for whey," advises Sturgeon, "It is the purest form of protein. It also has the best absorption rate. So, for instance, if you take in 60 per cent of the egg, you take in 70 or 80 per cent of the whey."

What they do is heal muscle, so are best taken, mixed with water or a smoothie. after a workout. "They won't store as fat," says Sturgeon, "so you won't gain any weight, unlike carbohydrate supplements."

Where some weight loss tablets once contained ingredients like ephedrine, most are now much safer and regulated by law. "Make sure you buy from a reputable company," cautions Sturgeon. "They should have details of clinical studies they've been through."

In terms of ingredients, as well as caffeine you might find something called white willow bark, which is a derivative of aspirin and aids transportation of the active ingredients through the blood stream. Then there will be the company's own branded form of metabolism stimulant. "They increase the thermogenic response in the body, which means they burn fat from the inside. You normally take them before food, so that 20 minutes later, by the time you eat, your metabolism is so high it'll just burn the food straight off."

But while they are scientifically proven to work, there can be side-effects. "Insomnia is a huge one," says Sturgeon. That's because each tablet can contain the equivalent of around two shots of espresso, and you could be taking four a day.

"Plus you could have elevated blood pressure and heart palpitations. You should always consult your doctor, and avoid them if you have any kind of medical condition, especially thyroid or heart conditions."

This article was first published in Scotland On Sunday, 3 October, 2010