Diet books routinely top the best-seller lists, and new plans come out seemingly every day. Do they work? Will any of them be right for you?

If you are considering one or more popular diets or exercise plans, you owe it to yourself and your health to make sure their claims are valid.

Ask yourself : Does the diet plan …

• Promise a quick fix?
• Encourage or require you to stop eating certain foods, food groups or products?
• Rely on a single study as the basis for its recommendations?
• Contradict recommendations of reputable health organizations?
• Identify “good” and “bad” foods?
• Just sound too good to be true?

If you answered yes to any of these questions, keep looking—for a plan that is backed by solid science, lets you keep eating your favorite foods and allows for flexibility.

Meanwhile, be realistic about weight loss. It really comes down to basic math.

“There’s no panacea for weight control,” says Cathy Nonas, R.D., a spokesperson for the American Dietetic Association. “It’s all about the calories you put into your body versus the calories you burn.”

Her suggestion? Eat a balanced diet of mostly fruits, vegetables and whole grains as your base, and accompany it with daily physical activity to help your body burn calories.

“Budget yourself, just like you would your finances,” she says. “If you overspent in the calorie department one day, try to make up for the in the exercise department the next. Over time, if you save up calories, you are able to have that once in a while splurge and not feel like you’ve blown your calorie budget.”