Originally Posted by SSP

I highly doubt that your 200 lb friend is only consuming 1300 calories per day. That's a very low level, even for a small-bodied post-menopausal woman. For an active adult male, that level is very low and runs the risk of vitamin and mineral deficiencies (assuming no supplements).

It's more likely that your friend's metabolic rate (basal + exercise) has lowered to the point that it now matches his caloric intake...the fact that he is not gaining or losing seems to point in that direction. As we lose weight, the body's daily caloric requirements go down, so the level of food consumption that promoted weight loss at 300 lbs will no longer do so at 200.

To continue to lose weight, he needs to:

1) Eat Less

or,

2) Exercise More

or,

3) Do some of both.

Since he's already exercising pretty consistently, I think the answer is #1.