Nutritionist is a broad term used to describe someone who makes recommendations about diet. There is little oversight in this field. To be a certified dietitian - nutritionist, as opposed to someone who merely uses the title nutritionist, one must pass certain criteria in New York for example. Usually an undergraduate degree in nutrition is required, although in our programs we usually prefer someone with a graduate degree.
In his book "Fat Chance" Robert Lustig M.D. turned the food industry on its head. Our entire food supply is, according to Dr. Lustig, engineered to produce food addiction and obesity, even in young children. The evidence seems to point in his favor.
For this reason, we have great respect for the benefits that a qualified dietitian / nutritionist can provide in educating people about food. However, one of the crucial problems with the medical model in treating weight loss is the tendency to take people who are only trained in food and give them responsibility for a wholesale shift in patient lifestyle. The statistics are clear on this matter. Long term success in weight loss has eluded professionals who do not have respect for the complete psychological and meditative aspects of the weight loss process as it impacts lifestyle decisions. Of course, a registered dietician or nutritionist with more complete training in these fields (extensive meditation experience and at least an M.S. in a psychology field) is a wonderful, albeit rare, resource.
We normally recommend registered dietitians be used for education on food, which is limited in scope, and leave the counseling to those trained in that field. It is also important to find a dietitian who is aware of the effects of processed food on obesity. The calorie in vs. calorie out model of weight loss misses important aspects regarding the impact from the types of calories. We have encountered nutritionists in this field who have recommended highly-processed meals, high-sugar meal replacement bars, artificial sweeteners, and other such foods that are an impediment to healthy weight loss.