Maximum weight loss per week?

Hi!

Someone has to clear this up for me.  I was told a few days ago by a friend that for healthy weight loss, you shouldn't lose more than 1% of your body weight a week.

This definitely makes sense - 2lbs a week for a 200lb individual, 1.4lbs a week for a 140lb individual etc.   It would also explain why weight loss slows as we lose weight, and ties in with the decrease in BMR as weight is lost.  However, is there any scientific reasoning behind it? Or is it just a simplified formula to make weight loss approximations easier?

Thanks in advance!

Ali =]

There was a study that said that you can have a deficit of, max, 31 calories per pound of fat. So if you know your body fat %, you can figure out how many pounds of fat you have, multiply by 31, and that's the max deficit you can have.  If you go above that, you will start burning calories from sources other that fat.

But what I've heard from many is that even that 31cals/lb of fat is optimistic, and if you want to ensure that you aren't burning off non-fat (muscle for instance) you should keep it lower. 1% of total weight is one rule of thumb. 1-2lbs per week is another rule of thumb, but in the end, you have to go with what works with your body. Slower, in general, is going to be more maintainable in the long run, so in general, it's not worth it to push the limits.

^^ I have not heard that, interesting.  I'm assuming that it's 31 calories per lb of fat per day?  It does seem high then, but maybe that's the ABSOLUTE max that you should be going for. 

I think 1% is just a reasonable guideline, keeps people from having major deficits and expecting to be able to safely lose 10lbs a week, which is a stretch...

Yes - that's 31 calories DEFICIT per lb of fat per day. So if you are 135lb, 15% body fat, you could have a deficit of 630 cal/day (1.25 lb/week loss). If your bf% was 20% at the same weight, you could theoretically have a daily deficit of 840.

Now, I'm 135. I have no idea what my bf% is, but assuming it's in that range, I should be able to carry that deficit, and I can't - I don't lose if I have that large a deficit. In fact, I'm not sure if I could continue to lose at 500 cal deficit - I kind of plateaued into my goal weight, and I've been maintaining since May... I'm going to try to lose a few more pounds, so I'll have to see what works for my body now.