Crazy scale readings? muscle loss?

water weight.

Don't know your weight loss history. It could be any # of things, but you won't lose that much muscle mass in a week.
Water "weight" may be a part of it. Make sure you are drinking enough, as it is possible that you are a bit dehydrated.

It's not unusual for me to lose 5# in a week. Usually it happens after I plateau for a few weeks, then the scale will suddenly drop a pound or two at a time over the course of a week. It's just the way that I lose weight.

Your body is burning calories expecting they will be replenished (because you usually eat back your exercise calories and aren't this week). So now that you're not eating back your calories, you're going to have a huge loss. (Probably some muscle, but also just more in general.) BUT... After about a week of this, your body will realize it's not going to be getting the calories it needs for the activities it's doing, and your weight loss will slow down dramatically, stop completely, or you may even gain some fat.

I would be happy you had a week like this, but go back to eating back your exercise calories next week so you can keep making improvements (both weight loss and fitness). If you truly are losing nothing at all by eating back your calories (not just only .5 - 1 pound per week, which I know is slow and frustrating but is also true when you get close to goal weight, but truly losing zero, week after week), then maybe try only eating back 75% of your calories. Or maybe try having one week like this (where you don't eat back) per month, but the rest of the time eat back your calories so your body burns them the most efficiently.

I know slow losses are frustrating, but they are the most likely to stay off!!

Hi,
Don't weigh yourself so often! Once a week - same day/same time will give you more accurate information.
Keep up the good work.
Barbeliza

I disagree completely with this poster. What scientist takes one reading and then adopts it as law? None. Take your weight daily as long as you realize that your weight varies from day to day, up and down - it won't hurt you as long as you don't get easily disappointed. Track your weight and you will have a better view of where you are in weight loss (your trend should hopefully always be going down).

Now, to be more on topic. I can't tell you if that's muscle loss, but you will probably start to see a slow down and gain back very soon. If I were you, I'd start eating back some exercise calories again to see if you can keep your metabolism guessing. Are you continuing to do strength training?

I see both points that each of these poster's are trying to make. You can weigh in everday, just make sure you have ONE day that is your official weigh in day and record it. That way you can keep more track of what you are losing each week by looking at what you weigh on the official days.

great advise!

Hi,
Don't weigh yourself so often! Once a week - same day/same time will give you more accurate information.
Keep up the good work.
Barbeliza

I disagree completely with this poster. What scientist takes one reading and then adopts it as law? None. Take your weight daily as long as you realize that your weight varies from day to day, up and down - it won't hurt you as long as you don't get easily disappointed. Track your weight and you will have a better view of where you are in weight loss (your trend should hopefully always be going down).

Now, to be more on topic. I can't tell you if that's muscle loss, but you will probably start to see a slow down and gain back very soon. If I were you, I'd start eating back some exercise calories again to see if you can keep your metabolism guessing. Are you continuing to do strength training?

Agreed. Scientists like MORE data points to get any overall trend.

I lose weight pretty weirdly too - I weigh myself every day so I have motivation to carry on when I've lost a pound or two.
The most I have lost was 9lbs in 3 days (through eating a 1200cal diet with little or no exercise and actually up to 200cal over) but I often lose a bit, put it back on and then it's off again easy as that.
If you put it back on again in a couple of days then up your water intake as it helps your weightloss to drink extra but it's great motivation to think that you weighed x-amount a couple of days ago and that the weight isn't stuck!

Of the 9lbs I lost I put 7lbs of it back on in 2 days and then lost 8lbs in another 2 days - again doing very little exercise and usually going over my daily calories.
PS. I'm not just lazy I'm itching to go out for a run but I broke my ankle quite impressively 11 weeks ago and now have 2 plates, 6 short and 2 long screws holding it together so it'll be about September before I'm cleared to go any faster than a walk (or hobble at the moment)!

I'm sorry to hear about your ankle. I wish you a speedy recovery!

Don't forget to measure biceps, neck, waist at the navel, and your thighs as well and trend this data.

You'll want to measure your waist at the navel if you're a guy. Women should be measuring at the smallest part of their torso (usually a couple inches above the navel) to get their waist measurement.