There are a lot of people who advice on diet and nutrition on the radio, in the net, newspaper or TV. The people giving such advice might be scientists, reporters, or just another person who has a new or their own idea on nutrition.
There are some weird theories handed over from the past, which swears by Vitamin C. The other thing is that do not have cheese and fruits at the same time.
Ultimately, a layman is confused and does not know which diet to follow and whom to trust.
There are many people who will advise you with diets which you can follow. Nevertheless, it is always better to go by the advice of a professional nutritionist.
They are normally people who have undergone a proper formal training and have obtained their degrees in chemistry, physics, biochemistry or biology. They are mainly involved in studies in relation to the effect of food on animals and human beings.
Nutrition related advice could as well come from people who do research in nutrition. They are people who are professionals in their own field, like medicine or sociology.
There are people who specifically focus their attention in the field of nutrition. However, generally a nutritionist should have basic qualification in science and a degree in nutrition.
There are dieticians who can give perfect information about nutrition. They are people who are qualified in nutrition, food and science. If is a suffix of RD after the name, it means the person has finished their internship in nutrition and dieting and has passed the exam of the American Diet Association.
Last, but not the least, there are reporters and writers in nutrition who supply you with a lot of information. They provide information on the scientific and medical effects of food. For instance, a writer who focuses in sports medicine.
Irrespective from whom you get the advice; you should keep in mind it has to pass a simple test. That means if some diet sounds very weird, may be it really is. Therefore unless you feel it is reasonable, do not go ahead with it.