In a single word.....NONE.  If every diet that claimed to be the one which kept us lean and thin, we would all be out enjoying A LOT more foods b/c we could just diet it off.  RIGHT?  It's very unhealthy to deprive our body of necessary foods.  Our bodies need a proportionate amount of Protein, Carbohydrates, and Fats in order to function on a daily basis.  The second we start to deprive it of one of those sources we are hurting ourselves. 

Each diet out there is different in its own way and has some valid scientific research, but the problem is that it only focuses on one small part of the body or nutrition and just "neglects" to inform us on everything else.  Now a days low carb and high protein seems to be the in thing.  Calories from carbs are the first thing our body uses for fuel, following a low-carb diet forces the body to quickly use this energy, then revert to stored carbs (known as glycogen) from the liver and muscles for energy. Since water is stored in the body with glycogen, you lose water as this glycogen is used for energy. Therefore most of the weight loss that occurs at this point is water and not fat.

Once these stored carbs are used up, the body then relies on protein for energy and as a result, compounds called ketones are produced. These can be dangerous, particularly for people with medical problems such as heart disease, hypertension, kidney disease, and diabetes because the brain relies on glucose for energy, but ketones don’t provide energy for the brain. The body therefore tries to eliminate ketones through the liver and kidneys, which puts a severe strain on these organs because of the toxicity of ketones to the body. For people with metabolic problems, ketones are particularly hard to metabolise and eliminate. Due to the high level of ketones produced in a low-carb/high-protein diet, you may also experience dehydration, weakness, nausea and, in severe cases, gout and kidney problems. 

The most important thing to remember when looking to change your eating habits is just that, changing your eating habits.  Dieting is a quick fix to a lifelong concern.  By watching what you eat and making sure you have a wide variety of foods there is no need to cut back on any one source.  Some key points: make it a long term goal and you will be able to enjoy those "bad" snacks every now and again.  Enjoy foods from all four food groups.  Watch your portion sizes, remember restaurants usually serve you portions which are 2 sometimes 3 sizes too big.  Dont be afraid to take half home!

 (source: http://www.ivillage.co.uk/dietandfitness/experts/nutrexpert/articles/0,,252_175381-2,00.html)

What is a trans fat?

Trans fats are manufactured fats formed by adding hydrogen gas to vegetable oil through a process called hydrogenation. A small amount of trans fat is found naturally in milk, dairy products and some meats. Trans fats are used commercially for making margarines and shortening. They can increase the shelf-life and add flavour and stability to many packaged products.

What are the health concerns of trans fat?

Trans fats increase the risk factors for heart & blood vessel disease. The effects on other areas of health like some

cancers, diabetes and allergic disease are uncertain

How do I reduce trans fat in my diet?

On prepared and packaged foods, check the amount and kind of fat shown on the Nutrition Facts panel; limit those foods with trans and saturated fats. You can also check the ingredient list on packaged foods. If it contains hydrogenated oil, partially hydrogenated oils or shortening, then it likely contains trans fats.

Source: Dieticians of Canada website (www.dieticians.ca)

What's So Important About Fruits, Vegetables And Grains?

Diets rich in fruits, vegetables and grains are healthier. These foods are high in vitamins, minerals, dietary fibre and low in fat. Eating plenty of these foods may help to protect against cancers of the throat, stomach and colon and cardiovascular disease.

Canada's Food Guide to Healthy Eating recommends five or more servings of grain products every day. Try a variety of grains, like whole wheat, oats, rye, or brown rice. Look for breakfast cereals with at least four grams of fibre per serving.

Canada's Food Guide recommends five or more servings of fruits and vegetables. Choose dark green and orange fruits like carrots, broccoli, spinach, cantaloupe, apricots and peaches. Include citrus fruits like oranges and grapefruit, as well as tomatoes, dark greens, broccoli and peppers in order to get plenty of vitamin C

Does a healthy person need vitamin and mineral supplements?

For most people, eating a variety of foods as suggested by Canada's Food Guide to Healthy Eating will provide all the necessary nutrients. The average healthy person does not require vitamin or mineral pills, even on a stressful day.

Nutritional supplements may be recommended in some circumstances. Some of these are for women who may become pregnant, are pregnant or are breastfeeding; infants, people who omit entire food groups from their diets, and those on very low calorie diets. There may also be medical reasons to use vitamin and mineral supplements. Your physician and registered dietitian can help advise you of your specific vitamin and mineral requirements as too much of certain nutrients can be dangerous.