Published: Oct 15, 2010 2:57 PM EDT
Updated: Oct 15, 2010 11:57 AM EDT

FORT MYERS, Fla. - Myth: Cutting carbohydrates helps you lose weight

Doing it the wrong way can also make you feel rotten and unhealthy. Carbs are to this decade what fats were to the last: food demons. Truth is, though, you need them for energy. And, like with fats, some are better than others. Experts suggest a minimum of 130 grams of carbs a day - a far cry from low-carb diets that start with 20 grams or less. Short-term effects of such diets include fatigue, constipation and irritability; long term, you could be putting yourself at risk for heart disease and colon cancer. Fad diets aside, what may matter most is how refined the carbohydrates are. The best idea is to cut back on refined carbs such as soda and foods made with white flour, while loading up on healthier carbs like whole grains, fruits, and vegetables.

Myth: Diet foods help you drop pounds

They can actually do the opposite. You may be doing yourself more harm than good by scanning labels for the lowest calorie and fat counts. Prepackaged diet foods can have a lot of sugar and trans fat. As with carbs, it's the quality of the fat, not the amount, that makes the difference. Monounsaturated fats (found in nuts, olive oil, and avocados) and the polyunsaturated variety (in corn, soybean, and safflower oils) help your cardiovascular system, improve weight loss, and are crucial for absorbing beta carotene from vegetables like carrots. Trans fats and saturated fats, on the other hand, have been linked with heart disease and even cancer. A recent study found that replacing just 30 calories of carbs a day with the same amount of trans fats nearly doubled the risk of heart disease. Replacing the same ratio of carbs with monounsaturated or polyunsaturated fats, on the other hand, lowered the risk of heart disease by 30 to 40 percent. So consider boosting your good fats by adding nuts to your morning cereal or avocado to your salads. Just watch your daily calories to keep them in check.

Myth: The more you cut calories, the more weight you'll lose

That can actually hurt you. Cut your calories too far - below 1,200 a day - and you'll end up with a double whammy that quickly decreases your metabolism and muscle mass. To get the most out of the calories you do eat, choose whole foods such as produce, fresh meat and fish, and whole grains that are as close to their natural state as possible. They have a higher "nutrient density" than refined foods, because they pack more vitamins and minerals into fewer calories.

Myth: Dairy makes you fat

Cutting dairy just shoots you in the foot (and fat cells). Combined with calorie control, a dairy-rich diet can nearly double body-fat reduction and weight loss and help prevent weight gain. Part of the reason is the hormone calcitriol, which helps conserve calcium for stronger bones while telling fat cells to convert less sugar to fat and burn more body fat. The result is leaner fat cells and a leaner you. Stick to the government's latest dietary guidelines, which recommend three servings of low- or nonfat dairy a day.

Myth: Brown equals whole-grain

There are lots of whole-grain poseurs out there. Look for labels where "whole-wheat" or "whole-grain" top the list. It's worth the extra effort: More and more research is finding that whole grains reduce your risk of many chronic ailments, from obesity and diabetes to cardiovascular disease. The extra fiber in whole grains is key: It makes you feel full, which means you eat less. It also helps level out the peaks and valleys of insulin that a meal produces. An added boost: Whole-grain foods tend to be higher in vitamins B and E than refined grains.