Our genetics are nearly identical to those of our early H. Sapien ancestors from 100,000-200,000 years ago. The human genome changes at a rate of .01 percent in every 100,000 years. We are genetically wired for a lifeway that is all but gone now, and our health reflects this.
- Robb Wolf in the Paleo Solution
Our body is amazingly efficient if we allow it to be. It has a starvation defense system intended to save you from a famine. The same system can work against you whenever you go on a calorie restricted diet.