Eating yeast does not cause yeast infections. It has been scientifically proven, so whoever told you that is an idiot. When you eat baked goods, with or without yeast, they are comprised of carbohydrates. Your body breaks carbs down into sugar. Yeast that is naturally occuring in your body feeds on sugar. You need to get checked for diabetes. People with high blood sugar are prone to yeast infections
If you take antibiotics for extended periods of time, this can cause yeast infections. The naturally occuring bacteria in your body eat the yeast. If you kill that bacteria with antibiotics, you will get an increase in yeast.
Make sure that when you have sex, your partners fingers and penis are clean. Always clean yourself up after intercourse to prevent yeast infections.
So, to recap, yeast eat sugar and bacteria eat the yeast. Eating a yogurt a day with live yogurt cultures can help to prevent infections as well. Using one vaginal suppository a week can also keep yeast infections in check. Eating yeast, however, has absolutely nothing to do with yeast infections. Make sure you get yourself checked for diabetes as soon as possible.