Diets: the big, fat lies

Think you can lose weight by skipping breakfast, spending an hour in the gym or sticking to 'low-fat' snacks? Then think again. Kate Hilpern explodes the myths behind the tips

Most dieters struggle to lose weight – and even if they succeed, many still pile the pounds back on. It's little wonder when you consider the number of myths associated with dieting.

Skipping a meal can help you lose weight

The opposite is true – we gain weight when we skip meals because our metabolism slows right down as a result of storing fat. Your body assumes you're starving and goes into survival mode.

Skipping breakfast is particularly futile. "One study found that people skipping breakfast were nearly five times more likely to be obese," says nutritionist Sara Stanner, of the Breakfast Panel, which promotes its benefits. "One reason for this is that it prevents you from having high-fat and high-calorie snacks during the morning."

Your body has gone through an overnight fast and when you break that fast, you give your brain the food it needs to perform, explains Azmina Govindji, dietitian and spokesperson for the British Dietetic Association. If your brain fails to get this kick-start, you inevitably start craving the kinds of food that will raise your blood glucose and brain glucose quickly. "It's usually unhealthy, high-sugar foods that have the fastest effect," she says.

If you really want to lose weight, eat both meals and snacks. Eating little and often is now recognised as the best way to keep your metabolism on an even keel. It will also stop you overeating at the next meal.

Fats are bad

"Not eating fats can make us fat," says Fiona Kirk, nutritionist and author of author of So What the F*** Should I Eat "Omega 3 fatty acids – found in oily fish, some nuts, seeds and beans – can inhibit fat storage in the body by a complex process where they limit the activity of the genes that make the enzymes required for fat production. They also increase thermogenesis, the internal body heat system that accelerates calorie burning. When we eat foods rich in the Omegas we not only accelerate fat burning, but the feeling of fullness they create also stems hunger and reduces cravings."

Failure to incorporate fat into your diet leads to symptoms of deficiency from the inside out, adds Marilyn Glenville, a nutritionist specialising in women's health. "I regularly see women who refuse to touch avocados, oily fish and nuts. As a result, they suffer from things like dry, lifeless hair, soft, easily frayed nails, painful joints, arthritis, cracked skin or dry skin, as well as poor wound healing, depression, mood swings, fatigue and lack of motivation."

You can 'work off' a burger in the gym

"It's common for people to try to offset unhealthy eating habits with exercise, for example equating 30 minutes running on a treadmill to a chocolate bar," says David Fletcher, personal trainer at Odyssey fat loss specialists.

"The trouble is our bodies respond differently to exercise and for some, cardiovascular activity for a sustained period of time, such as a one-hour jog, can be of little benefit when it comes to dropping body fat." He blames calorie counters on exercise machines for raising people's hopes. "They don't take into consideration individual body composition, including your levels of muscle mass, that ultimately determines how much fat your burn."

There's no doubt that exercising is good for the waistline. "But the sums are tough – to lose a pound of fat through exercise, most people need to run 35 miles," says nutrition and weight loss expert Laura Williams. "Far better to restrict calorie intake."

'Lite' foods and drinks are good for dieters

"Foods described as 'low-fat' or 'fat-free' are often higher in calories than standard products, thanks to the extra sugars and thickeners used to boost the flavour and texture," says Juliette Kellow, dietitian and adviser to Weight Loss Resources.

Some low-fat products contain up to 60g of sugar per serving – almost as much as a 600ml bottle of Coca-Cola (70g). Cereal bars are among the worst culprits. While many are lower in fat than chocolate bars, they often contain just as much sugar. Fletcher says that even "diet" foods that contain fewer calories and less fat can be sinister. They are often laced with sweeteners, which contain xenoestrogens, he explains. "These disrupt your hormonal profile and can cause fat storage."

Debbie Saxton, nutritionist and author of The Complete Lifestyle Guide, points to two further components of many diet products. "Phenylalanine and aspartic acid both stimulate the release of insulin and leptin, hormones that instruct your body to store excess energy as fat. In addition, phenylalanine can drive down serotonin levels when consumed in large amounts. Serotonin helps the body feel full and low levels of the hormone lead to food cravings, in particular junk food."

Two US studies have even linked diet drinks with weight gain. Scientists at the University of Texas found that the risk of obesity was highest in those people only drinking diet soft drinks, while a study by Purdue University, Indiana, offers an explanation why. The artificial sweeteners the drinks contain tell the brain a lot of calories are about to be consumed. When that doesn't happen, you eat more to compensate.

Avoiding carbs helps you lose weight

Foods high in carbohydrate have had a rough time in the past few years, thanks to the popularity of low-carb diets such as the Atkins diet. But there's no evidence that carb-rich foods are more likely to make us gain weight than any other food.

In fact, carbohydrates are the food group most likely to keep you feeling fuller for longer and are the most important source of energy in the diet, according to Jane Griffin, UK sports dietician and consultant to Zotrim. "Anyone who follows the low-carbohydrate, high-protein diet will soon begin to feel lethargic and irritable," she says – the very time you're most likely to go in search of the cookie jar.

"Your body needs carbs," agrees Govindji. "Forget the notion of no-carbing if you want to be healthy and keep weight off. You need carbs to provide you with fibre and high-fibre foods tend to be more filling than low-fibre foods, so they could help you to eat less."

The best carbs are those with a high glycemic index (GI), that raise your blood sugar levels steadily and keep them up, says Govindji. For the GI of individual food and drink types, visit www.glycemicindex.com.

Diets are the best way to shift pounds

There are zillions of diets and research shows that one in four of us are on one at any given time. But none of them is proven to work. Scientists at the Kissileff Laboratory for the Study of Ingestive Behaviour at the University of Liverpool found that calorie-restricted diets create powerful cravings for the very foods you are trying to avoid.

"Dieters not only have a greater preoccupation with the foods they have been forbidden, but with food more generally – with the result that they have stronger urges to eat more frequently and a greater feeling of being out of control with their eating," says the centre's director, Jason Halford.

The researchers also found that dieters have impaired cognitive function and slower reaction time compared to non-dieters.

Detoxing is good

"Detox regimes are based on the assumption that our bodies are not able to deal with waste products," says Griffin. "If you have healthy kidneys and a healthy liver, you should have no problem dealing with toxins. Of course it makes sense not to have too much caffeine, alcohol or high-fat foods, but a healthy balanced diet will help the body withstand any toxins."

Short-term detox diets probably do no harm, she says. "There may be nasty side-effects such as headaches, nausea, bloatedness and a change in bowel habits. As for long-term detox diets, they should never be considered. The low intakes of vitamins and minerals can cause anything from reduced immunity to infections and excessive weight loss that could even encourage a possible eating disorder."

Other things you should know

* Some salads contain more calories than steak and chips. Croutons, bacon, mayonnaise and oily dressings are the worst offenders.

* Being overweight is often blamed on wheat intolerance, but in fact, less than 0.1 per cent of the population suffers from this condition.

* Contrary to popular belief, eating late at night is not more likely to make you put on weight.

* Losing weight won't reduce all the health risks of being obese. Better not to pile on the pounds in the first place.

* Yo-yo dieting can carry more health risks than not dieting in the first place.

* Many people assume red meat is bad for slimmers, but good, lean meat is fine.