Intermittent fasting

The classic 5:2 method is to eat maintenance calories on the 5 days, and something like 500 on two non-consecutive days. Weight loss is triggered entirely by the two low days.

However, those rules aren't something that need to be followed precisely in order for weight loss to happen. Any way of getting calories eaten manageably less than total calories burned will result in weight loss, and we can use weekly averages as a guide, distributing the calories any way that works for us.

If the 5:2 method makes the process easier for you, or you feel like that method has benefits beyond weight loss as such, that may be a good method for you. Other people here have succeeded while using it.

For most women, unless petite, quite inactive and fairly old, 1200-1500 would be deficit calories, rather than maintenance calories.

If that's true for you, eating 1200-1500 on five days and 500 two days could be setting you up for very fast weight loss. Faster weight loss isn't better weight loss: It's harder to stick with long enough to lose a meaningful total amount of weight, and it increases health risks.

It may be fine in your case, but since you didn't say anything about age, height, weight, activity level or where the 1200-1500 target came from, it's hard for anyone else to say.

Best wishes!

FWIW, the average woman with those characteristics, if quite sedentary, would expect to maintain current weight somewhere around 1800-1900 calories daily, maybe a bit more. (Of course individuals can differ from average, but average is a reasonable starting assumption.)

Just as an example, if that pretty-sedentary average woman were to eat 1600 on 5 days of the week, 600 on two days of the week, we'd expect her to lose roughly 1 to 1.2 pounds per week, maybe even a bit more, as an average body weight loss trend over several weeks. That seems like a sensibly moderate loss rate to me for a woman at 207 pounds.

Of course, an average woman who is more active would burn more calories, so lose faster eating at those calorie levels - how much faster depends on how active.

Why do I think that? While MFP will give you reasonable calorie estimates for maintenance based on your profile information, I used an outside calorie estimator, since I didn't want to reset my own profile values to see MFP's estimate. I used this one:

https://www.sailrabbit.com/bmr/

That calculator's estimate may differ a bit from MFP's estimate, because there are several different reasonable science-based estimating methods, but they usually fall in the same ballpark for most people. Then I estimated how many calories below her estimated maintenance calories that average woman was eating over the course of the week, subtracted that from a week's worth of maintenance calories. That would be the weekly calorie deficit. Dividing that weekly calorie deficit by 3500 gives a rough estimate of average weekly weight loss because a pound of body fat equates to approximately 3500 calories.

The arithmetic looks like this, if we assume maintenance calories of 1800 for the example:

Five days a week: (1800 calories burned) minus (1600 calories eaten) = 200 calorie deficit each of those 5 days.

Multiply the 5-day deficit by 5 to calculate its impact on the week: 5 times 200 = 1000.

Two days a week: (1800 calories burned) minus (600 calories eaten) = 1200 calorie deficit each of those 2 days.

Multiply the 2-day deficit by 2 to calculate its impact on the week: 2 times 1200 = 2400.

Add up all the deficits for the whole week: (1000 calorie deficit from the 5 days) plus (2400 calorie deficit from the 2 days) = 3400 calorie deficit for the whole week.

Finally, turn the week's calorie deficit into an estimate of pounds lost: (Roughly 3500 calories in a pound) divided by (3400 calorie total deficit over the whole week) = 0.97 pounds, which I rounded to one pound because this is all so estimate-y and that's pretty close. 😉

If you stick fairly close to a given calorie routine for 4-6 weeks, your average weight loss per week will give you an idea how close to average you are, and you can adjust your calorie goal if necessary to make your calorie goals more personalized and your weight change more predictable. If you still have menstrual cycles, calculate average weekly weight loss by comparing body weight at the same relative point in at least two different cycles, because hormonal water weight shifts can distort results.

Any of that is still just estimates, but personalizing the estimates is useful for people who turn out to vary noticeably - even surprisingly - from average. Most people are close to average, though. If the multi-week experiment comes out pretty close, or comes out to any sensible loss rate, really, it's fine to stick with that same routine as long as it's easy enough to stick with long enough to lose all the weight a person wants to lose.

Weight loss will slow down some as we get lighter - a smaller body burns fewer calories than a bigger one, generally - but that's OK. Losing slower when lighter is usually a good thing. If it slows down unacceptably much, obviously it's fine to decrease calorie goal a bit, or add some more movement to the average day to burn a bit more.

Weight loss arithmetic can be fun!