There are more opinions on dieting than most people have time to keep up with. How do you know what to take out and what to keep to arrive at your ideal weight? The doctors at Mayo Clinic have some advice on how to pick the best weight-loss plan.

• Involve your doctor—Review any medical problems and medications that you need to take into account before you embark on a weight loss plan. Discuss your ideal weight and how to safely include exercise into your plan.

• Consider your personal weight-loss issues—Unless you take into account your lifestyle and personal preferences, any weight loss plan will be doomed to failure before you even begin. This way you can tailor a plan that will work best for you.

• Look for a safe and effective weight-loss program—It’s hard to ignore all the claims celebrity dieters make on TV. The safest and most effective weight-loss plan will be flexible, give you balanced nutrition with foods that you enjoy and are readily available to you, include physical activity, and allow you to lose weight at a steady, and slow, pace. Successful weight loss plans allow you to not only lose weight, but maintain your weight at a lower level. Make sure that your food plan is one that you will want to follow for the rest of your life.

Although well promoted, many of the popular diets fail because they aren’t lifetime plans. Some of these suspect plans include:

• Fad diets—You’ve seen the advertisements for these diets promise that you'll lose a large amount of weight in a short period of time. And often you can lose the weight without changing your eating or exercising habits. They may require that you take pills, supplements, skin creams, patches, fat blockers, special combinations of foods, or other diet aids. Fad diets can work in the short term. But for the majority of dieters, the weight will quickly return.

• Glycemic index diets— The glycemic index was originally developed to help improve blood sugar control in diabetes. It classifies carbohydrate-containing foods according to their potential to raise your blood sugar level. Glycemic index diets are based on the premise that controlling blood sugar levels leads to weight loss.

• Low-carb or high-protein diets— Low-carb diets limit how many carbs you can eat every day, sometimes to as little as 10 percent of standard dietary recommendations. While restricting carbs, these diets allow a large amount of protein and fat, a practice that may lead to nutritional deficiencies and other health problems.

• Low-fat diets— Low-fat diets focus on cutting excess fat out of your diet, usually by limiting fat intake to about 20 percent of your total daily calorie intake, the percentage of fat that is responsible for obesity. However, if all you watch is your fat intake, you can still overeat on other types of food. Too many calories, no matter the source, will add pounds.

• Meal providers and meal replacement diets. With meal replacement diets, you replace one or two meals a day, with a low-calorie, nutritionally complete shake or meal bar. Then you eat a healthy third meal, between 600 and 700 calories. Meal providers give you ready-made meals that are usually calorie controlled and often can be tailored to your tastes and health needs. These diets can be costly, and absent of fresh fruits and vegetables.

• Very low calorie diets. Your doctor may recommend a very low calorie diet if you need to lose weight quickly before a medical procedure or if you have serious health problems because of obesity. You should not try these types of diets without medical supervision, as you will need close monitoring to avoid complications.

Combining a healthier diet and more activity is the best way to lose weight and keep it off for the long term. The doctors and nutritionist at Mayo Clinic advise you to take your weight loss and weight maintenance one day at a time and surround yourself with supportive resources to help ensure your success.