EVERY woman starts a diet in the hope of getting slimmer, feeling healthier and looking as hot as she possible can.

She doesn't want to lose her hair, develop saggy skin and see her boobs flatten before her eyes.

But those are all some of the worrying side effects that weight loss, through badly managed exercise or dieting, can cause.

Girls Aloud singer Sarah Harding is just the latest in a long line of female stars who have experienced a dieting downside.

This week, she complained about her boobs shrinking due to losing weight on her band's latest tour.

The gorgeous star said: "When we tour, we burn off so much energy we lose weight. I wouldn't mind putting some back on. I want my boobs back."

But sagging breasts are just one of the side effects of weight loss.

Dieting or extreme exercise can also lead to depression, older-looking skin, hair loss and bad breath, as well as leading to obsessive behaviour, fertility problems or leaving you at risk of suffering from an eating disorder.

Experts have pinpointed the following side effects and offer their advice on how to avoid them.

SAGGY SKIN

When stars have been crash-dieting or losing weight too fast, one of the biggest tell-tale signs around the limbs, especially the arms, is saggy skin. That happens when you lose weight too fast, meaning the skin that covered your larger body frame, has not contracted along with the rest of your body.

Christine Mitchell, a Scottish group leader with Weight Watchers, said: "We always tell our members that you need to start exercising as soon as you start losing weight, as you need to tone up.

"If you leave it too late, the skin can become like a blown-up balloon with the air let out of it, as the body gets smaller then the skin sags. But toning up and doing any kind of exercise will help."

SMALLER BOOBS

With breasts made up of fatty tissue, once you start to lose weight and reduce fat, then, unfortunately, you can, like Sarah Harding, see your chest shrink.

Lillia Sinclair, a nutrition and health expert at Heaven Health fitness boutique in Glasgow, said: "Unfortunately, it depends on your body type.

"Some people can exercise and lose weight and still have a large chest and some people will lose a cup size. "Make sure you eat a lot of protein in your diet and exercise such as weights and resistance training will keep the muscle firm and minimise it as much as possible."

Christine added: "There is no way to lose weight from a particular part of the body, or avoid losing weight, there is no boob diet, no bum diet.

"You just have to keep a healthy diet and lose as much or as little as you are happy with for the body shape you want."

BAD BREATH

One of the most well-known side effects of carb-free diets, such as Atkins, is bad breath.

It occurs as a side effect of the ketone production occurring from the type of food intake and, according to the experts, is unavoidable, but treatable.

Lillia said: "You need to make sure you eat a lot more fruit and vegetables, and drink a lot of water."

Christine added: "The bad breath you get is a symptom that your body is not getting the food that it needs and if you cut out a food group, then your body is missing something.

"The best way to avoid that is to have a healthy and balanced diet."

DEPRESSION

People who are regularly dieting or losing weight can feel low or depressed, even if they are doing well on the diet.

That happens when the person dieting has cut essential nutrients, minerals and liquids from their regular intake and they lose energy and health as a result.

Lillia advised: "If someone came to me and had been depressed after dieting, then I would say you need to be taking more fish oil supplements and vitamin B12 complex, then cut out all grains for four weeks.

"A lot of people suffer from low energy, low moods and anxiety, and that is down to poor nutrition."

OLDER SKIN

Dieting can reduce the health of the skin, making it appear older, dryer and less healthy than it normally does.

That means it has been starved of nutrients and vitamins because you have been dieting.

Lillia said: "Your skin is the biggest organ on your body, if you are lacking in magnesium, zinc, essential oils, or are dehydrated, then your skin is one of the first places it will show up.

"Make sure you are eating good-quality food and supplements. And when eating, don't just count the calories, count the quality of the calories you are taking in and eat better food."

While Christine believes there is a certain type of dieter that ends up looking older.

She said: "You can always tell people who crash diet and don't eat healthy balanced food, because they look older around the eyes. And what's the point of spending all your time losing weight just to look terrible."

DIET OBSESSION

Losing weight, however you do it, or over exercising, can become an obsession. And it can affect those who reach and exceed their target weight or who never get close to it.

Christine said: "The best way to avoid that is to go to an organisation that will help you and monitor you throughout your weight loss."

And Lillia added: "I try to tell people to focus on the food that they should be eating and the nutrients they should be taking in, and not to focus on what they are not, or should not, be eating.

FERTILITY

Crash dieting, over exercise or even just losing too much weight can be a real problem for a woman's fertility.

Periods can stop, your hormones are affected and you are not eating enough nutrients to help grow a healthy baby.

Lillia said: "If you crash diet, it massively affects your hormonal balance and this is a very serious problem you need to deal with very quickly.

Christine said: "If you are eating an unhealthy diet and losing too much weight, then you could be doing all kinds of damage to yourself that you can't see at the moment."

OSTEOPOROSIS

The bone thinning disease is one of the most serious side effects of unhealthy diets.

It is caused by high levels of toxicity and acidity that build up and strip calcium from the bones when your body is malnourished due to a poor diet.

The best ways to avoid this is to make sure you have a balanced diet, instead of astrict weight-loss regime and exercise to keep the bones working.

Lillia said: "Even just walking helps, because the impact keeps your bones strong. If you have toxicity and no exercise, your blood will take the calcium out of your bones."

RISK OF EATING DISORDER

According to studies, anyone who undertakes any kind of fad weight loss diet is five times more at risk of developing aneating disorder, such as bulimia or anorexia, than someone who has a regular eating balance. The experts say the best way to avoid that is to make sure your eating, weight loss and exercise are regulated and you maintain a healthy diet.

Christine advised: "There are so many myths out there, that someone who wants to lose weight can end up starving themselves because they think they have to feel hungry for it to work.

"And that is definitely not the case, so you should make sure you get the right advice from people who know what they are talking about."

Lillia added: "People can become obsessive about their weight, even if it is all in their head."

HAIR LOSS

One of the most shocking side effects of dieting is hair loss. That occurs when you suffer from a minerals deficiency and your body starts to shed hair as a symptom of your system being malnourished.

Although rare, the side effect is well-known to nutrition experts, who can get you back on track and reverse the process with a stable eating plan.

Lillia said: "The body will tell you when it needs something and that can show up in the hair or other body parts so we need to be aware of that.

"I have seen it, but it can always be reversed and every case I have seen has been reversed with better diet, because it's all about mineral deficiency."