By:   Mridu Khullar Relph

To lose weight, the formula is simple: eat less and exercise more, right? In theory, yes. But in practice, following that course blindly may cause your diet to falter. Starving the body of calories actually slows down metabolism, as does too much exercise.

If you're getting dizzy trying to keep up with the latest diet information and frustrated because none of it seems to work, you may be fighting an uphill battle. Here are some common dieting mistakes to avoid:

Mistake #1: Eliminating all fats from your diet
Focusing entirely on low or no fat is possibly the worst nutritional concept of the century, according to Dr. Jonny Bowden, author and board certified nutrition specialist. He says that what most people don't realize is that fat keeps you full, helps prevent cravings and snacking, and most importantly, it has no effect on your fat-storing hormones (insulin), which carbohydrates drive through the roof.

Some fats, especially omega-3 fatty acids, are indispensable, says Melissa Majumdar, a registered dietitian, personal trainer and member of the Sinai Bariatric Surgery Team at LifeBridge Health in Baltimore. "Fat is important for brain function and has even been shown to prevent depression." Omega-3s and other unsaturated fats can be found in fish, nuts, olive and canola oils.

Mistake #2: Skipping meals
One of the biggest mistakes women make while dieting is skipping meals, especially breakfast. "Many women assume that by skipping breakfast, the most ignored meal, they are saving calories," says Robin Barrie Kaiden, MS, RD, CDN, CSSD, who worked for five years as a senior clinical nutritionist at Beth Israel Medical Center and the Continuum Health Partners Hospitals in Manhattan. "Or they think that just a coffee or piece of fruit suffices for a meal, and they can save their calories for later."

This plan, she says, tends to backfire because they end up hungrier towards the middle of the day and are likely to overeat. "Pyramid eating (small or no breakfast, medium lunch, large dinner) can lead to weight gain or prevent women from losing weight. This is because they eat most of their food at the end of the day and then go to sleep with no time to burn off the calories. The food just sits in the stomach during sleep."

New York Times bestselling author Jim Karas agrees. In his forthcoming book The Petite Advantage Diet, Karas urges readers to eat around 400 calories for breakfast and to make sure to include protein and fiber-filled foods, such as fruit or whole wheat/whole grain breads. "Numerous studies show that the more you eat for breakfast, the less total calories you will eat throughout the day," he says.

Mistake #3: Eating too fast
"It takes your brain about 20 minutes to recognize that your stomach is full," says Kaiden. "If it only takes you 10 minutes to scarf down a meal, you will not feel full and will continue to overeat and ingest excess calories." To avoid this, she says you need to allow your body the time to realize if and when it is full. Chew slowly and you'll not only be helping break down the food more and aiding in the absorption of nutrients, but you'll tend to enjoy it thoroughly as well.