Losing weight demands focus plus mental and physical energy. If you want to succeed, you can't just plunge in. You need to make a commitment and prepare yourself. Part of that preparation is determining whether now is the right starting time.

"It's challenging to lose weight, and it requires a commitment, as many people who have tried know very well," says Donald Hensrud, M.D., a preventive medicine and nutrition specialist at Mayo Clinic, Rochester, Minn. "But if there is another factor present, such as stress, lack of time or a physical limitation that limits physical activity, it can make a challenging situation even more difficult."

Your success depends on your readiness to take on this challenge. These questions can help you judge whether you're ready to lose weight.

• Are you motivated to make long-term lifestyle changes that require eating healthy foods and exercising more? Knowing that you need to make such changes is a positive first step. Also, carefully consider whether you're set to face this challenge.

• Have you fully assessed what's going on in your life now and during the next several months? Be aware that you may set yourself up for failure if you're distracted by other major problems, whether they involve your personal relationships, job or finances. If necessary, give your life a chance to calm down before you start. Making the lifestyle changes necessary to achieve and maintain a healthy weight needs to be among your highest priorities.

• Do you truly believe in losing weight slowly and safely for better health? Losing weight at a relatively slow pace has proved to be safe, healthy and effective over the long term. You want to aim for a loss of 1 to 2 pounds a week. That may seem agonizingly slow in our instant-gratification society. But if you make improving your health a long-term goal, speed won't matter.

• Do you believe that you can change your eating habits? Everyone has his or her own challenges that may spell disaster in any weight management program. But it's not just the types of foods that get in the way. It can be when, where and how you eat them. A good weight-loss program helps you identify and eliminate the food triggers that make you overeat.

• Do you have family, friends or both who will support your weight-loss efforts? It certainly helps to have someone in your corner. In fact, the more the merrier. If you don't, consider joining a weight management support group.

• Are you willing to find ways to be more physically active? Becoming more active is essential to losing weight and keeping it off. You'll also feel better and have more energy.

• Are you realistic about your weight-loss goal? Remember, losing as little as 5 percent to 10 percent of your body weight can reap health rewards if you're overweight or obese. Start small. Work on losing 4 to 8 pounds a month. Just because you wore a size 6 dress or jeans with a 28-inch waist in high school doesn't mean that you should now. Ask your doctor how much weight you can safely lose.

• Are you willing to record your food intake and duration of physical activity, and will you make time to do so? Keeping records increases your chance of success. Although this takes time at first, the amount of effort decreases as you adopt healthier habits. You'll be pleasantly surprised by how helpful it is to track your progress.

• Are you willing to look at past successes and failures in weight loss and other areas of your life to see what has motivated you and kept you working on obstacles to success? Changing behavior isn't easy. It takes time and effort. You'll run into barriers on your path to success.

• Do you view changing your eating and exercise habits as a positive, even pleasurable, experience? Losing weight and keeping it off requires patience and hard work. You'll experience both short- and long-term effects. More nutritious eating habits and increased activity will soon have you feeling better. Most important, there will be health benefits.

• Have you resolved any eating disorders or other emotional issues that make it difficult for you to achieve a healthy weight? If you have a tendency to binge and purge or to starve and overexert when you exercise, or if you're depressed or anxious, you may need professional help.

• Do you believe that achieving and maintaining healthy weight is a lifelong process that requires you to change your behavior, eating habits and level of physical activity? Are you ready to make that commitment? Achieving and maintaining healthy weight is a lifelong process. But it's worth the effort.

If you answered yes to all of these questions, you're ready to make the lifestyle changes necessary for permanent weight loss.

If you answered no to one or more of these questions, then you may not be ready. And that's OK. Explore what's holding you back and face those obstacles. In some cases it may be a simple matter of timing. For instance, you may need to resolve other problems in your life. In other cases, you may need to work on related issues — such as your feelings toward weight loss or your willingness to commit to permanent changes.

You may be able to make these changes alone, or you may need the help of a doctor or dietitian. "Educating yourself about the process of successful weight loss and maintenance is a start," says Dr. Hensrud. For example, learn more about the dietary changes necessary for losing weight. Dr. Hensrud also says that a behavioral-based program can help you deal with stress or other life issues that need to be modified before attempting weight loss.

If you're ready for weight loss, remember to look long term when times get tough. "As you become more physically active and make dietary changes," says Dr. Hensrud, "do these things not as short-term drudgery, but rather as enjoyable lifestyle changes that will persist indefinitely."