What on earth is a 30 fat diet? I have never heard of it before. Are you talking about a diet for people who are thirty years of age? Your question does not make any sense and this is the only thing that I can understand from it. Please be clear about what you are asking in the future. There is not specific diet that thirty year of people need to follow and all you have to do is to eat right and stay healthy. Exercising regularly also helps. Eating low fat products and lean meat is a good way to ensure that you stay in shape.