Is it possible to lose 45 pounds in the first 30 days?

I know a 23 year old female who claims to have lost 45 pounds in the first 30 days after a VSG.  She has done little in the way of exercise, but is following the diet to the letter.

I have my doubts, simply because of the math.  If a pound of fat is 3500 calories, then 45 pounds is 157,500 calories.  That means she would have to average a 5250 calorie deficiency every day for the month.  I read that a 210 pound person would burn almost 4000 calories by running a marathon.  She is probably 250 lbs, so lets increase the expected calorie burned to 5000 for running the marathon.  Assuming she ate the minimum 800 calories per day, that still leaves her 9 pounds short of the 45, if she ran 30 marathons.

I would be much more inclined to believe that she could burn 2000 calories a day, just like most of us, and with the 800 calorie per day diet, she would be down 10 pounds for the month.

As a male, with considerable muscle mass, I expect to only lose 10-15 pounds a month after I have my VSG in September.  If It can actually be 45, I would be both very surprised, and very happy.

Please share your experience.

Bert

Lets start with - 3500 cal deficit is not one lb of fat.  It is a myth. Google that. 

Can a person lose 45lbs within one month post op ? Yes they can. But most likely it will not be fat loss, but mostly water + fat + muscle loss. 

During my surgery I "gained" 12 lbs of water due to IV and sweeling.  I lost that plus additional 15 lbs during first month post op. And that was AFTER I already lost most my carby - water weight of 18 lbs during 4 weeks preop diet.  Depends how you count the loss...I lost a lot ...

Instead of worry about what others lost and how they see it - concentrate on your losses. 

Also some women are like sponges - we can retain a lot of water due to hormonal times.  There is a lot of hormonal dumping first few moths - and if someone had high blood pressure, diabetes, or sugar issues - they could have also retained a lot of water on top of the hormonal issues - andf they can lose that when BP, BS normalized. 

So since (according to you) the 3500 calorie thing is wrong, and you lost the 12 pounds of water that they put into you (would have lost that without diet), and you lost 15 pounds post surgery, and you lost 18 pounds before surgery, and that all totals 45 pounds, it is possible to lose 45 pounds in a month?

To my crude math, it appears that you lost 15 pounds in the first month after surgery.  15 pounds is an incredible amount to lose, and it is very commendable.  It just isn't 45 pounds.

Why am I concerned about what someone else lost?

Because while each person is different, general ideas about how much I may lose is gleaned from looking at other people's loses.

Just out of curiosity, I went back to check my log book. From 12/17 when I started the pre-op diet to 01/16, I lost 44 lbs.

So fromy experience, it's possible.  My question is why you are so worried about someone else's loss? 

I had Roux-en-Y, so I am not certain about other types, but I lost 29lbs the first week and was down 50 at just under 3 months.  It doesn't seem unreasonable to me, depending on her starting weight and all that.

Sure it's possible.  Everyone loses differently.  I have certainly never lost that much in a month, but I doubt a person is lying to me if they say that they have!

Anything is possible. 

I lost 60# give or take a pound or two depending on which scale in my first post op month. 

Worth pointing out is how overweight one is. 250 on a short or very short woman is a ton of weight and likely a much higher bmi than you'd think.  250 on my frame is actually not far from the weight my doctors want me to get to. 

It's possible, especially if the person in question was very, very heavy. The more you have to lose, the faster you CAN lose.