Calorie Diets

You should also know that doctors are not omniscient. There are huge gaps in their knowledge. Often times, their diet information is gleaned from reading summaries in magazines. There is a reason there are dietitians and doctors. Dont be afraid to ask your doctor why they recommend that intake. What is their math based on, etc.

2 lbs a week means you need to create a daily deficit of 1000 cals.

Everyone's body burns calories just existing, and that varies. Age, sex, height, current weight all play a role.

Then we burn calories living. Showering, making breakfast, etc.

And then through exercise. Going to the gym, running, etc.

All of those calories added together equal your current TDEE (total daily energy expenditure) or maintenance calories. Yours may be quite high if your weight is also quite high, if you're quite active, etc.

This means that MFP thinks your body burns 3300 calories in a day, including lifestyle (but excluding exercise -- you have to tell MFP after you exercise, then it factors it in for you and gives you more to eat!). If that's true, 1600 creates a very steep deficit -- 1700 per day (more in deficit than you are eating). That'll be 3-3.5 lbs a week.

Sometimes, for larger individuals, a rate of loss that high is considered acceptable. I have heard that it's partly that the trade-off is good (very high weight is more likely to be impacting your health right now) and partly that, with more fat to lose, you can live off of more of the fat with fewer ill effects. I don't know if that's true.

You can keep going by your doctor's number, and probably just not get upset with yourself if/when you eat over a bit? (Meaning, aim for 1600 but remember that up to 2300 would still be a very good deficit you're making that day!!) Or you can try trusting MFP. Or go by the doctor for a few months, then MFP. Or pop yourself in the middle. 2000? Or vary your target based on how you feel. Or eat less throughout the week and more on weekends. (Example, give yourself more room around holidays, around your period, around difficult times like a move or a road trip.) Learn about the math and make informed decisions about what you're eating. It doesn't have to be "on target" or "whatever, I guess, because I went over". You have lots of options!

I don't know your current health situation, but assuming you're not in danger, there's nothing else your doc has said to you about it, 2 lbs a week is still a great loss and might be more sustainable if you are finding 1600 difficult. (Cannot stress enough to pay attention to your doc if your doc has indicated a medical reason to lose weight rapidly.)

The reason you were prescribed the caloric deficit is what determines the answer to your question.

Is the prescription in response to a specific issue where immediate weight reduction is more important than sustained reduction, or is it a prescription to improve your lifestyle where success is more dependent on being a good long term turtle as opposed to a fast short term hare!

Generally it is considered that 3500 calories equals 1lb of fat loss. Generally it is considered safe to reduce your body weight by up to 1% per week. In some cases this can easily be more than the 2lbs per week recommended by MFP. In other cases 2lbs is more than 1% and not a great choice!

Dangers of rapid weight loss?

Higher risk of non compliance/failure because you are too hngry. More likely that more of the weight you lose will be lean mass as opposed to fat. Not developing the long term sustainable habits you will need in order to eat less and move more for the rest of your life. Thinking that you are on a diet with an end date as opposed to viewing food and movement/exercise differently than before. All these things take time.

Assuming your doctor is not bananas and based on a 2300 recommendation by MFP you have a long way to go. So to me the risk of non compliance due to being too hungry would be my biggest concern.

So, if there is a medical need to reduce now, then this discussion is pointless and you should stick to your medically supervised weight loss.

If the doctor had just yelled at you because of your general shape and said go on a diet, eat 1600 without coming up with a plan and reasons.... my gut feeling is that you might be more likely to stick it out if you aim for a 1% of body weight reduction.

Of course your logging should be as accurate as possible. Yes, you should be eating back your true net exercise calories or you would be inducing a larger than planned deficit.... etc etc.

Did your doctor refer you to a weight loss specialist to help you come up with a plan?