You can get a degree of "NATUROPATHY", which is basically training in nutritionist, herbal and natural remedies. It is a 4 year degree program. If you want to finish your studies as early as possible,, then 1 or 2 year diploma and bachelor degrees in the field of diet and nutritient will be suitable for you. Look for universities in your city that offer such degrees.
It is important that You get a good degree related to Nutrition for a job as a nutritionist. First of all you need to have an undergraduate degree in science subjects. Then you would need a master's degree in Nutrition. Or you can also do post graduate diploma in Nutrition. Here is a link to the website of The British Dietetic Association. It is an official forum which provides detail trainings and courses. Read the details and get yourself involved in one.