Clare is right, it can take quite a few times for a baby to even think about trying a new food. When offering new foods, it can help to mix them in something that he does like, then gradually adjust the mix until it's all new food and little or no favorite food. Babies will often eat really weird things, so you might even try mixing veggies in the fromage frais to help him accept them. For the shortened nursings, it's possible that he may just be getting more efficient, unless you can tell from pumping that he's definitely taking less. And don't rule out teeth, either...teething can throw a wrench in everything for a few days.
Even if he has lost a few ounces, try not to worry just yet. Babies' appetites and preferences vary a LOT from day to day, and he isn't going to starve himself. If he doesn't want to eat, then your best bet is to respect his appetite and let it go. He may also be picking up on your anxiety, so try to relax and don't push the issue. I'd be willing to bet that he's teething and will be back to himself before you know it...please let us know how it goes!
