July 28, 2009 -- Grocery stores offer a myriad of ways for shoppers to think they are buying healthful food -- low-fat dressing, vitamin-infused cereals, or the trendy sports drink.
But ask a nutritionist about these products and they may just sigh or shrug their shoulders. Either the research isn't there to support them, or the public has gone astray in a modern attempt to be healthy.
"Vegetables have many different nutrients that we don't understand," said Dr. Louis Aronne, founder and director of the Comprehensive Weight Control Program at New York/Presbyterian Hospital/Weill Cornell Medical Center.
Aronne said experts estimate there may be upwards of 30,000 nutrients in food that have yet to be investigated -- some of which may even be signaling your body that you're full.
But from what nutritionists do understand about nutrients there are some pitfalls the public can avoid while trying to eat right.
Take, for instance, fat. A Monday morning National Public Radio feature explaining how a drizzle of fat helps the body absorb nutrients excited Aronne and his colleagues.
"I think it's important for people to remember that fat is not a poison. When I heard this I thought of people who think that eating raw food, and eating no fat at all, is the best way to go and that's not necessarily true," said Aronne.
Scientists have long known that certain nutrients dissolve in water (vitamin C) and certain nutrients dissolve in fat (beta-carotenes which turn into vitamin A). But in the past five years researchers have put this theory to the test feeding people healthy foods with and without fat.
When it comes to most brightly colored vegetables and fruit such tomatoes, carrots, peppers, spinach -- studies have shown eating the veggies with a bit of fat dramatically increases how much beta-carotene the stomach delivers to the blood stream. Cooking vegetables like carrots, or finely chopping a variety of vegetables, can also help people absorb their nutrients.
"Maybe one of the problems is we've taken all flavor out of food," said Aronne, author of "The Skinny: On Losing Weight Without Being Hungry."
According to Aronne, reaching for the low-fat dressing every single time or skipping that little bit of butter in the pan may actually be doing your diet a disservice. Not only will you bypass some beta-carotene, people are unlikely to eat a lot of unappetizing vegetables.
"Would you be better off having the vegetables if, god forbid, they had a little butter on them?" he asked.
The no-fat, raw food movement is not the only popular health habit that baffles nutritionists. The following are some common nutritional missteps in dieting that doctors in contact with ABCNews.com would like to share.
Going Vitamin and Supplement Crazy without Consulting Doctors
Although researchers say they only have a small grasp on the way vitamins, minerals and nutrients affect the human body, it seems the public has few qualms about grabbing supplements galore.
In 2007 an estimated 40 percent of adults in the United States used supplements, according to the National Center for Complimentary and Alternative Medicine. Echinacea supplements, fish oil and garlic were some of the more popular purchases aside from vitamins.
"I see a lot of people who take mega doses vitamins, a pill for vitamin A, a pill for vitamin C," said Elisabetta Politi, Nutrition Director of the Duke University Diet and Fitness Center in Durham, N.C.
"But I encourage everybody to go speak with a nutritionist before self prescribing multiple vitamins," she said.
Politi stressed that although some vitamin supplements might be good, more isn't always better.
"For example, iron fortification is something controversial. We want to prevent anemia… but adding iron to everything in our food supply might not be good," Politi said.
While iron can function as an antioxidant and help protect cells from cancer risk, Politi said "Iron in excess has been shown to promote oxidation instead of preventing it."
Fortified Foods for All? Not All Nutritionists Are Impressed
Politi also takes issue with the common practice of fortifying food -- fortified cereals, fortified health bars, even fortified water.
"I'm not particularly fond of food being enriched with a lot of vitamins -- you really don't know how much you're getting," said Politi. "The FDA allows a 20 percent margin of error."
Instead of spending extra money on new-fangled fortified health food, Politi just recommends one daily multivitamin and a varied diet with plenty of fruits and vegetables.
Yet even when patients stick to the basic meals, many nutritionists find their patients have been playing timing games with their food: No breakfast ever, no dinner after 8 p.m., no snacking at all.
Toying with the Timing of Meals
Mayo Clinic dietician Jennifer Nelson said one of the most popular nutrition myths she hears is that skipping breakfast saves calories.
"Studies have shown that breakfast skipping is associated with a higher body mass index compared to those who eat breakfast," Nelson wrote in an e-mail to Abcnews.com. "If you eat a healthy breakfast, the overall quality of the diet improves, and breakfast can help regulate appetite."
Nelson said the same goes for the myth that snaking is bad. "Actually, snacking on healthy foods can actually improve the overall nutritional quality of a person's diet - and help control appetite," she wrote.
Drinking Your Weight Loss Away
Often patients trying to lose weight may fall short not so much on what they eat, but what they drink. Politi said she frequently sees patients who fall into the trap of consuming a lot of sports drinks at the gym.
"My fitness colleagues tell me that sport drinks are only needed when you exercise for over an hour and most people really don't exercise that long," said Politi. "Especially if you're trying to control your weight, it's better to drink water. The [sports] drink is some extra calories you don't need."
Amid all the confusing marketing and government recommendations, Aronne suggested the public just go back to eating your vegetables.
"This is what your mother has been telling you," said Aronne. "If you eat your vegetables first and get the good nutrition that you need, then you can feel satisfied."