If this were me in real life, I would seriously consider spending more time on my personal hygiene before the party takes place. And possibly tidy the place up a bit. You know, drastic situations call for drastic measures.
If you don't want an orchestrated feeding frenzy quite so close to the guests' arrivals (though that will work too if your food doesn't make them all sick), another approach is to be sure someone is stationed by or near the door or wherever the guests are gravitating to upon arrival -- usually they will try to head for the one who arranged for the party -- and engage each of them in conversation. Compliment them, Brighten Their Day, whatever you have to work with depending on your sims' traits and theirs. Bring them a drink or a coffee if you have those available. Give them something to do. Suggest they chat or dance ("Convice To") with someone. Start up a time consuming 4-person activity like a video game, table tennis, shoot some pool, have a game of dominoes. Pull them by the hair and drag them into a hot tub. That kind of gracious host thing.
And if you don't have much to work with on your home lot due to its size or lack of funds, consider throwing a party on a commercial lot where there might be more fun things to hold their interest for longer.