I had an experience just weeks into my career that forever affected how I answer this question.
Our assignment for the first six weeks of our internship, was to follow a different therapeutic diet--low cholesterol, low fat, diet for kidney failure, etc. Our internship director wanted us to have more empathy for our future patients, who were being asked to make a major life change in order to follow our recommendations. I sailed through the assignment, actually enjoyed it…until we hit the 800 calorie diet assignment.
I became cranky, lost energy, started obsessing about food, and made it about 2 days before I started sneaking snacks. And then, midway through the week, I binged. Big time. And I swore, I would never, EVER, ask anyone who came to me for help, to go through what I had just been through.
So even though the standard way to prescribe a weight loss diet is to figure out how many calories it takes to maintain your current weight, then subtract 500 calories per day for each weekly pound you wish to lose, I have refused to inflict that madness on anyone.
I've even pushed back when working with eating disorders, where as the dietitian, I was often badgered by my treatment team members to just keep piling on more calories until we hit the total that resulted in weight gain. For the simple reason that there is no way you can help a person learn what healthy eating is when you're treating her by feeding her two to three times what she is realistically going to need to eat in order to maintain a healthy weight.
So what do I do? Easy. I calculate how many calories it would take to maintain the ideal weight, and leave it at that. So if you're 180 lbs and you want to weigh 140, eat what it takes to maintain 140. Get used to the idea. Don't deprive yourself. Get off the starve/binge cycle and really learn what normal people do in order to maintain"normal" weight.
It's not a magic, speedy weight loss. (Or gain). It's slow and steady. But the reality is, if you envision the person you'd like to become, and start to make choices that such a woman would make, you will become her.
Do you wish to become an anxious, food-obsessed, unhappy person? Or do you wish to become a nurtured, nourished person with energy for herself and those she loves?
Dieting will bring you one, and healthy eating the other.
Which path most reflects your intentions?