Eventually, your body will catch on. You will go into a "weaning starvation mode."
Personally, I can go into a mini-starvation mode anytime I dip below 2,000 calories so I make sure that NEVER happpens even if I have toi have a bowl of cereal last thing at night.
Lately alas, going UNDER 2,000 hasn't been my problem...OVER 2,200 another story.
If I tried sliding to 1,500 fopr any length of time, it would take me a YEAR to get my metaboolism back on track. Just holding in the low 2,000's has made me resistant to weight loss at those amounts.
Yep, it doesn't take an earthquake to trigger the starvation response...it's nature's way of dealing with less.