Quoting Squeaky McGee:" If you're suddenly eating much less, your metabolism is probably slowing down to compensate. Start exercising, or do something to increase your energy expenditure."
Quoting cunning cuniculi:" id say your body is still adjusting to some major nutrient changes. i wouldnt say its going into starvation ... [snip!] ... its getting. i think i heard that a lot of bad foods can sort of block the absorption of certain good foods into your body too."