First, you have to remember that the aim of a weight loss program is to take weight off and KEEP IT OFF. Yo-yo dieting puts stress on your body that can make losing weight harder and harder and packing it back on far too easy. It's important to choose a diet plan that will help you make changes to your eating habits that will last a lifetime.
If you're a yo-yo dieter, you probably have a history of swinging between very restrictive diets and then returning to 'normal' eating once you've lost the weight that you need to lose. You've proved that you have willpower now what you need is re-education. Instead of choosing a strict regimen that you'll abandon when the diet is done, commit to following the recommendations for healthy eating from the USDA, and add half an hour of exercise to your daily routing five times a week. You'll establish healthy habits that will take off the pounds - and help you keep them off forever.
Secondly, decide just how much help you need. What motivates you? Are you a private person by nature, or do you do best with a lot of social support? Are you a strong-willed person who can decide to do something and 'just do it', or will you need help overcoming temptation?
If you thrive on social motivation, joining a weight loss program like Weight Watchers or TOPS (Take Off Pounds Sensibly) might be the best option for you. You'll have social support, motivational rewards and weekly check-ins to help you stay on track and give you goals to aim for.
Next, do you do best with regimented, strict instructions that tell you exactly what you should do step by step, or are you happiest and more comfortable with a little flexibility?
If you do best when you have strict guidelines to follow and like routines, then look for a diet that gives you daily menus with precise measurements and foods to eat. While that may feel restrictive to many people, the trick is to do what works for you. In fact, once you reach your target weight, you can subscribe to a healthy eating or living magazine that has daily menus.
If restrictive diets and inflexible menus aren't for you, then try a diet that gives you the option of mixing and matching your meals within certain parameters. Whether you count carbs, calories or exchanges, a diet like the Atkins, Weight Watchers or the Zone diet gives you some flexibility within the prescribed 'allowed foods'.
Finally, how much weight do you have to lose? How long have you been trying to lose it? Will quick results keep you motivated, or is slow-and-steady progress all you really need?
Try a Quick-start with the Atkins diet to strip off the early weight - a lot of it water weight - quickly so that you will see results immediately. When your results from such restrictive eating are slow, pick up the activity by adding a little more exercise and vary your diet a little - but count your calories and carbs. Aim for a steady 1-2 pounds per week, but if you need an extra boost, drop back to a more restrictive pattern to give your metabolism a little kick. The trick is to never stay with an extremely low calorie diet long enough to slow your metabolism. Just drop down and pick up the activity level long enough to wake yourself up again.
