The most important things to do is to try to encourage him to drink more. I've found that adding a little low sodium chicken broth to their water makes it smell better and they tend to want to drink more than they usually would.

As for eating...I would actually try some canned dogfood or canned catfood (cat food generally works better because it contains more fat and calories). I've also found that warming up the food in the microwave will make it smell stronger, and as we all know, dogs generally won't eat what they can't smell.

If he still won't eat, you can try rubbing a little Karo or pancake syrup on his gums to give him a little sugar burst. Sometimes just that little bit of extra energy can be utilized to help get them to eat...try the syrup and then if he perks up, offer the warmed food. Sometimes all they need is a little push to get over the hump in regards XXXXX XXXXX and then they'll do it on their own.

If he's still not feeling better by Monday, you should absolutely give your vet a call, just to ensure that everything is good with him. Hopefully this is just a little bout of gastroenteritis (digestive upset) that will pass, but it's always better to have him checked if he's not improving.