To add to what saggy said, it is not so much a lowered health status as that's debatable (and actually life extensionists have "proven" via studies that it is one of the most effective ways to add years to your life and thwart disease).
So, in context and with respect to a bodybuilder's needs, you will wreck your metabolism (downregulate thyroid and leptin levels) and thusly, screw yourself royally in the end as you create a new "set point" with regard to daily caloric intake. Example: You will lose weight (some muscle) with the low calorie regimen but you will have to THEN maintain that bird-eating for the remainder of your life or you will invariably GAIN WEIGHT at only "1,800/day".
Additionally, and from a more acute perspective, as underlined above, such dieting/eating strategies will cannibalize your muscle thereby also lowering your daily metabolic "needs" (then lowering resting BMR = lowered "resting" calorie burning).
It's a multi-pronged dead-end road IF you plan to carry any muscle on your body.
If your goal is to simply lose weight and be built like a skinny runner with garden hoses for arms, then go for it.