Successful and lasting weight loss requires commitment.  It is easy to commit to something when your coworkers, family, and friends are watching.  It is harder to do when you are bored and home alone.  

You must make your lifestyle healthier by permanently adopting better eating and exercise habits.  Remember weight loss is 80% diet, so all the exercise in the world will not keep you thin.  Crash diets and fad diets may create a calorie deficit and help you shed a few pounds, but they will not last long if you do not develop a follow-through plan to keep the weight off.  In the long-term, neither a crash or fad diet provide lasting results, and neither is thought to be healthy.  

Nutrition is important for us to maintain efficient function and quick weight loss diets undermine a proper nutrition.  Often, these fad and crash diets limit your ability to acquire the proper nutrient balance which makes them dangerous.  Even worse than malnutrition, these diets often are downright adverse and make you suffer.  You are more likely to end up binging in response to the drought of food you have created.  Instead of losing weight, you will be more likely to gain weight in the long run.  

The bottom line: Commitment is easy when you are you have peer pressure,  The key is pushing yourself when you are alone and avoiding the temptation to give in.