In simple terms, the way to easy and quick weight loss is to eat less and exercise more. But the hard part is knowing what to eat less of (and equally what to eat more of), amidst all the conflicting advice that we're bombarded with every day.

Fats aren't as bad for us as doctors, dieticians and even the government would have us believe. And carbs aren't as "energy giving" as we're told either, so were do we start.

To understand why we seem to be consuming more calories, we need to get back to basics and look at the three fundamental elements of our diet: carbohydrates, fats and proteins. We need to understand how they work together, whether we're in the process of getting fat or thin, and the role they play in our digestive system.

We'll start with protein, since the popularity of high-protein diets like the Atkins diet program has made it a hot topic.

Protein is an essential part of your diet. In fact, you are already half protein: 50% of your dry body weight is made up of muscles, organs, skin and hair, all forms of protein. We need this element to build and repair body tissues, and it figures in nearly all metabolic reactions. So if you're embarking on a quick weight loss program, or perhaps already on one, don't forget to make sure you include plenty of protein rich foods in your diet.

Protein is also a critical brain food, providing amino acids for the neurotransmitters that relay messages to the brain. The brain fog people experience on some diets is probably the result of diminished protein. This is also why it's not a good idea to skip breakfast on the morning of a big meeting or exam. Protein is literally food for thought.

The main sources of dietary protein come from animals: meat, seafood, dairy and eggs. Vegetable sources include beans and soy-based products like tofu. Unfortunately, protein sources such as red meat and full-fat dairy products are also high in saturated fats which are harmful to your health, especially your heart. This is why there is so much concern in the medical field about the popularity of high-protein/low-carb diets like Atkins.

The problem is not so much with the high levels of protein, but with the saturated fats associated with these proteins.

It is important that we get our protein from sources that are low in saturated fats, such as lean meats, skinless poultry, seafood, low-fat dairy products, tofu and other soy products.

One exceptional source of protein is the humble bean. Beans are just about a perfect food - they're high in protein and fiber, and low in saturated fat. No wonder so many of the world's cuisines have found a myriad of wonderful ways to cook beans.

We need to become more bean savvy. Nuts are another excellent source of protein that are relatively low in fat - as long as you don't eat a whole bowlful.

In terms of how you feel, protein is what leaves you feeling satisfied and well fed. Because it breaks down more slowly in your digestive system you feel fuller longer. This characteristic is key to the success of any quick weight loss program.