It is very common for toddlers to loose interest in food around age 2. There is just so much to explore, who has time to eat!!!
This is what I have experienced with my LG who is now almost 3:
1. If there is a serious decline in her appetite, to the level where she is only drinking milk, it is often tonsilitis or a cold. If there are any other symptoms like sleeping longer than usual, bad breath and iritability or fever get them checked out by your doctor. Loss of appetite is sometimes an indication of a sickness.
2. The last molars normally come out around age 2 - 2,5 years. It could be that as well.
3. Giving too much fluids during the day can spoil their appetite. Lots of water is always good, but too much coldrink/juice/milk can spoil their appetite.
4. Children who get frequent unhealthy snax like chips/flings/cookies and sweets do have less of an appetite. Every time my child had snax/sweets I was garanteed that the rest of the day she will eat less than usual.
5. I make "picnic platters" for her everyday. She loves the idea of "picnic food"!
I make a smorgasboard of healthy finger foods like: provitas, fresh fruit cut up in pieces (sometimes on a sosatie stick), cheese, red kidney beans, chick peas, celery, carrot sticks, cucumber, tomatoe, peanuts, raisins, cranberries, biltong, ham or other cold meat, pasta shapes, dry cereal like "nutrigrain". She would munch on this for a few hours.
6. I give her vidaylin with iron to make sure she gets an extra boost.
7. Never force them to eat. Don't turn food into a batlle. If they don't want to eat, don't make a scene, just take the food away and don't offer anything else untill the next meal. They won't starve themselves! Toddlers can go without food for a long time!