A diet myth is advice that becomes popular without facts to back it up. When it comes to weight loss, many popular beliefs are myths and others are only partly true. Here are some facts to help you sort through what you hear.

MYTH? Cut back on carbs to lose weight.

FACT:Carbohydrates come in different forms: simple and complex. Simple carbs found in foods like cookies and candy lack vitamins, minerals, and fiber. Cutting back on these sweets is a great way to eat healthier and possibly lose weight. Foods with complex carbs like whole-wheat bread, beans, and fruit, have lots of nutrients that are good for you.

• Cut back on simple carbs but keep complex carbs on the menu.

MYTH? If the label says "no-fat" or "low-fat," you can eat all you want and not gain weight.

FACT: Many low-fat or no-fat foods have added sugar, starch, or salt to make up for the reduction in fat. These "wonder" foods often have just as many calories, or more, than the regular version.

• Check the nutrition label to see how many calories are in a serving. Be sure to check the serving size too.

MYTH? Skipping breakfast makes you gain weight.

FACT: Eating a healthy breakfast can help you manage your hunger later in the day and help you to say "No thanks" to unhealthy snacks. No scientific studies have shown that skipping the morning meal leads directly to weight gain.

• If you are not hungry first thing, listen to your body. When you are ready to eat, help yourself to a healthy option like oatmeal with fresh berries.

MYTH? Eating at night will make you gain weight.

FACT: People who eat late at night do tend to put on extra weight. One possible reason is that late-night eaters tend to choose high-calorie treats. Some people who snack after dinner do not sleep well, which can lead to unhealthy cravings the next day.

• If you are hungry after dinner, limit yourself to healthy snacks such as low-fat yogurt or baby carrots.

MYTH? You cannot be overweight and healthy.

FACT: There are some people who are overweight with healthy blood pressure, cholesterol, and blood sugar levels. For most people, excess weight increases the risk for heart disease and diabetes. The longer you are overweight, the more your risk of developing disease increases.

• While you can be overweight and healthy, carrying extra weight will increase your risk for health problems down the line, but healthy eating and regular activity are good for you no matter what you weigh.

MYTH? Fasting can help you lose weight quickly.

FACT: Fasting is not healthy if you go hungry all day and cap it off with a huge meal that replaces all the calories you skipped earlier. Compared to people who lose fat by eating fewer calories, people who fast lose more muscle than fat.

• Look at your daily diet for empty calories you can cut out, such as refined grains and sugary drinks. Do not cut out meals entirely, especially without a doctor's supervision.

MYTH? You have to set modest goals if you want to lose weight.

FACT: In theory, it makes sense that if you set ambitious goals and do not reach them, you might give up. However, some people actually lose more weight when they set goals that make them push themselves.

• No two people are the same. What works for someone else may not work for you. Losing weight is a process. Be ready to modify your plan as you discover what works and does not work for you.

MYTH? Slow weight loss is the only way to lose weight and keep it off.

FACT: While it is true that many people who lose a lot of weight in a short time gain it all back, this is not true for everyone. Some people with overweight are more successful when they lose weight quickly, for instance, going from 300 to 250 pounds (135 to 112 kilograms) in less than a year.

• Slow weight loss might not be the only option for you. Just be careful to avoid fad diets that promise unrealistic results, they may not be safe. If you are interested in a diet that encourages faster weight loss, be sure to work with your health care provider to make sure you are getting all the nutrients you need.