No-Fat Meals and Other Diet Mistakes

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.