[Zimahl]

I’ve dropped 19 lbs in just under three weeks! This is a ridiculous loss of weight. It might even be unhealthy, I’m not really sure.

Oh, it's very unhealthy. That 19 lbs was probably mostly muscle you burned because you essentially went into starvation mode, Christopher McCandless style. There aren't enough calories in meat and (most) vegetables to survive on.

Safe weight loss is pretty simple and there's no other way around it. Cut out 500 calories per day, either by diet or exercise and you'll lose 1-2 pounds per week. Any more and you aren't burning the fat you have you are burning through your muscle.

[jc4p]

6lb a week can easily be a large loss of water weight for someone who's overweight, it's not maintainable but if it happens for more than a few weeks in a row is the time to be worried, not now. Also, cutting 500 calories per day is a weight loss of 1 pound per week (a pound is 3500 calories) :)

Oh, and it's very possible for someone who's untrained to lose more than a pound or two a week (by being on a bigger than 1000 calorie daily deficit) and still not lose muscle but instead make new muscle and strength increases, it's just harder.

[awj]

Even if this is 1/2 to 3/4 water weight loss, that still likely isn't healthy.

You're right though, without more information to supply context it's hard to judge what is "too much".

[edkennedy]

I would not be so quick to jump to conclusions. You can see his target weight is 250lbs, and the more weight you have the faster you can lose lbs.

[Zimahl]

the more weight you have the faster you can lose lbs.

This may be true at extreme weights but unless he's 5 foot nothing, 250 is not an extreme weight. To safely lose weight you have to cut calories but you can't starve yourself otherwise you aren't losing fat.