Yes, missing out on important nutrients is often a result of extreme dieting, including the sort of low-carb dieting in which dieters consume as little as twenty grams of carbs in the initial phase.

Carbohydrates are the basis of grains, fruits and vegetables, and milk also has a significant amount in the form of lactose. When you eliminate or severely limit these foods, you are likely to have a grossly inadequate intake of many essential vitamins, minerals, antioxidants, fiber and water that carbohydrates provide. You're also limiting the variety of foods that make eating more enjoyable.

Also remember that nutritional supplements can never replace the hundreds of plant phytochemicals (which include anti-cancer agents) in naturally-occurring carbohydrate-based foods.

Partly it's to do with new research that shows we consume too many refined carbohydrates, but generally it's because people like to think carb-cutting is the "latest and greatest" remedy for weight gain. However, like all latest-and-greatest remedies, this one is flawed. When low-fat diets were popular, people ate too many high-sugar foods to make up for calorie and satisfaction deficit. On low-carb diets, people now eat too many high-fat foods.

Although current marketing would lead us to believe that fat is now the "good guy" and carbs are the "bad guy", watching fat intake is still important. It's the type of fat that's the key - avoid deep-fried fats, saturated fats and instead include healthy fats such as olive oil, canola oil and omega-3-fats (in flax oil and some fishes).

However, there is something to be said for cutting out "bad" carbs as well - it's good to cut down on sources of refined carbs such as cakes, pastries, candies, soft drinks and table sugar. We Americans eat too many of those! But we should also increase our intake of healthy carbs from natural food sources.