Prescribed diets plans, such as Jenny Craig, The Zone, and The South Beach Diet are wildly popular, and often quite successful, at least in the short term. But they don't adequately address personal eating styles, family and work schedules, or exercise preferences.

Do you crave a diet that caters to your unique needs, instead of a cookie-cutter formula from a book or diet guru? Here's how to personalize an eating plan that helps you shed weight and keep it off for good.

The Best Diet: The One That Works for You

If you bristle at the thought of complying with someone else's idea of how you should shed pounds, the good news is that you don't need weeks' worth of expensive prepared frozen meals or a militant eating and exercise program to drop the weight. Even a slight decrease in calories, preferably on a plan that meets nutritional needs, is all it takes. 

"One diet is not necessarily any more successful than the next," says Joy Bauer, MS, RD, author of Your Inner Skinny: Four Steps to Thin Forever. "We know from research studies that almost any plan that reduces calorie intake results in weight loss, regardless of whether it's high-carbohydrate, low-carbohydrate, high in protein, or low in fat."

But here's the rub: Weight loss won't last unless you change your eating and exercise habits for good in a way that meshes with your food preferences, schedule, and lifestyle.

Dieter, Let's Get Personal

Before you begin designing your own diet plan, some self-reflection is in order.

"Knowing who you are and what you need is the most important information you can have when it comes to losing weight, eating healthy, and changing your lifestyle," says Heather K. Jones, RD, co-author of What's Your Diet Type? Use the Power of Your Personality to Discover Your Best Way to Lose Weight. "Our personality explains why some approaches to weight control work, while others fail."

Jones says dieting takes more than willpower, and that people who successfully lose weight and keep it off have simply discovered which approaches work for them and their unique personalities.

6 Key Questions to Answer

In order to design your own diet, Bauer and Jones advise asking yourself the following six questions:

• Do you prefer to eat three, five, or eight meals a day? Once you determine your desired eating schedule, divide your calories accordingly.

• How much time will you devote to food preparation? If you hate to cook, or have limited time, you'll need to simplify the preparation of healthy, fresh, and lightly processed foods.

• What type of support, and how much, do you require? Everyone needs some cheering on to succeed, especially when the initial enthusiasm for changing bad habits begins to wane. Family and friends, online weight loss communities, and diet buddies can help you when you're tempted to ditch your healthier diet and exercise program.

6 Key Questions to Answer continued...

• Do you love to dine out? You'll need to account for restaurant food by seeking out the calorie counts of the foods you eat most often.

• Will you require a daily treat to feel satisfied? If you can't live without a little something special every day, reserve 100 calories for a single-serve package of cookies or chips, or for a frozen treat, like a fudge bar.

• How much exercise can you reasonably do? Experts recommend at least 30 minutes a day of moderate physical activity, such as walking, on most days of the week, but you may have to build up to that, especially if you aren't physically active. Ask your doctor what's best for you.

Calculating Calories For Weight Loss

Diets don't work unless you run a calorie deficit by eating less energy than you burn.  Most healthy people without chronic conditions can safely drop no more than two pounds a week on a balanced diet.

Adhering to a daily calorie budget for weight loss is the crux of any successful do-it-yourself diet plan. Your calorie allowance is based on your age, sex, physical activity level, and weekly weight loss goals.

Once you have calculated your calorie level, the next step is figuring out what to eat for weight loss. Bauer says the best diet plans are based on whole foods, such as vegetables, fruits, whole grains, lean protein, and low-fat dairy foods, because they lay the foundation for a lifetime of healthy eating.

The U.S. Department of Agriculture's MyPyramid.gov web site provides a blueprint for healthy eating, no matter what your weight goal. The number of servings to include on a daily basis from each of the five food groups, and oils, is determined by the calorie level you choose for weight loss. MyPyramid.gov also provides information about proper portions for foods in each food group.

How to Design Your Daily Meals and Snacks

You know how many servings from each of the food groups you need. Now you need to decide how to combine them to make healthy, satisfying meals and snacks that keep temptation at bay.  Here are some basic rules:

• Have at least three meals a day.  Eating on a regular basis prevents extreme hunger that can wreak havoc on your resolve to eat better and exercise more.

• Stay fuller for longer by combining protein (found in the greatest amounts in foods from the milk and meat/beans food groups) with fiber (found in whole grains, vegetables, fruit, and legumes) at every meal and snack. Noshing on fat-free yogurt and an apple, or a hard-cooked egg and a small whole grain roll, is more satisfying than spending the same number of calories on soda crackers, which are very low in fiber and devoid of protein. 

• Conserve calories. Choose the lowest-calorie choices from each food group. For example, opt for 1% reduced-fat milk or fat-free milk instead of full-fat; 93% lean ground beef instead of 85%; and light popcorn instead of popcorn smothered in butter.

Prevent Portion Distortion, At Home and Away

All foods fit on a balanced weight control plan, but proper portions are paramount. Most people rarely go overboard on carrot sticks and celery, but it's a different story when it comes to cheese, pasta, fatty red meats, and other favorite foods.

If you're uncertain what constitutes reasonable serving sizes -- and let's face it, most of us are -- invest in a reliable kitchen scale, measuring cups, and measuring spoons to determine portions at home. If exactitude isn't your style, learn how to compare correct portion sizes to everyday objects, such as a baseball, a deck of playing cards, and a light bulb.

Correctly eyeballing portions is particularly helpful when dining out. It's a useful skill to have, because it's unlikely you'll be eating every meal at home.

"On average, Americans eat six meals a week away from home," says Hope Warshaw, MS, RD, author of Eat Out, Eat Right.

Even when you're dining on reasonable portions, the calories can add up.

"Research shows that restaurant food serves up more added fat and sugar and fewer fruits, vegetables, whole grains, and low-fat dairy than homemade food," Warshaw says.

That doesn't mean frequent diners are doomed to fail at dieting. However, it helps to limit dining out as much as possible by brining food to work and on the road, and by counteracting extra calories with physical activity.

Rely on books and the web sites of your favorite eating establishment for the calorie counts of the dishes you order. Always ask for what you need to limit calorie consumption, such as low-fat salad dressing served on the side, grilled meat and fish prepared with no added fat, and plain vegetables.