I have found that changing my diet does help my psoriasis clear somewhat. It certainly does help not to eat too much sugar. I have noticed that tomatoes worsen psoriasis. In addition eggplant can make it in a little worse. Over eating or under eating can also affect my psoriasis. Worse than eating too much and gaining weight is actually being on a diet and losing too much weight. I have noticed that when I was on the zone diet and I lost quite a bit of weight, my psoriasis flared quite a lot. In addition when at another time I lost some weight my psoriasis also flared.