Well, another new year is upon us and many people have made their new year's resolution to lose weight. There has been a lot of talk in the media about low carb diets. What are they? Do they work? Let's take a look at the low carb diet and why you should or shouldn't try one.

What is Low-carb?

The body runs on 3 main sources of fuel: carbohydrates, fats and protein. When carbohydrates or 'carbs' are used in the body as fuel, the body must secrete insulin. Body tissues have insulin receptors on them. We can think of these receptors as 'keyholes'. Insulin is like the 'key' that must be inserted into this 'keyhole' to allow the tissues (the 'door') to let the carbs 'in' as fuel. The problem is, when a person is eating a lot of carbs, the pancreas is continually pumping out insulin. When there is too much insulin ('keys') in the system, the tissues decide that they do not need as many receptors ('keyholes'). This is called 'downregulation'.

Downregulation, or the decreasing of insulin receptors, causes insulin resistance. Insulin resistance is recognized as a way for obesity and type 2 diabetes to develop. When the tissues do not have enough receptors to use the insulin present in the system, the  insulin continues to float around in the system. Insulin promotes fat storage in the body and tends to inhibit fat burning. As long as massive amounts of insulin are present in the system, it is thought that the body can not burn fat. This is where the low card diet can help you loose weight.

Low-carb diets were first made popular by the Atkin's diet. The idea behind low-carb diets is to avoid all carbohydrates and force the body to use protein and fat as fuel. Low-carb diet proponents argue that by not consuming carbs, insulin is not secreted in the first place, therefore downregulation does not have the opportunity to occur. They also claim that the smaller amount of insulin present in the system better allows the system to stop storing fat and begin to burn it.

When you are on a low-carb diet, your body does not have carbs to use for fuel so it must break down fat and protein for fuel. The byproducts of this breakdown are chemicals called ketones. Ketones are an alternative source of fuel for the brain and other tissues. So, in other words, the absence of carbs, and therefore the absence of insulin, triggers the production of ketones.

Since the production of ketones is triggered by low insulin, ketones can be produced in diabetic people who are low on insulin. In a diabetic person, ketones act as a 'low fuel' light like the one in you car that tells you when you are almost out of fuel. In this case, the presence of ketones mean you are almost out of insulin. The presence of ketones in a diabetic person can be dangerous, even deadly. It is never ok for a diabetic to have ketones. The treatment for a diabetic with ketones present is to give insulin.

The presence of ketones in a non-diabetic is not as big of a deal. Generally a non-diabetic person will still be able to produce enough insulin to keep ketone levels in check before they can lead to dangerous conditions like ketoacidosis, dehydration and coma.

The good thing about following a low carb diet like the Atkin's diet is you will likely loose weight quickly and will likely feel full or satisfied most of the time. The problem is, the minute you go off the diet, you will likely gain it back, quickly. Another problem with the Atkin's diet in particular is it promotes eating a diet high in saturated and trans fats. This is known through research to be harmful to your health. The Atkin's diet is also low in fiber which has been shown to reduce the risk of certain cancers and promote a healthy colon and weight. It is also devoid of other much needed nutrients that are typically found in fruits and veggies. Finally, the presence of ketones in your system can cause bad breath. This is because excess ketones in the body are excreted through the breath and the urine.

Low-glycemic Diets: The Healthy Alternative Low-carb Diets?

A compromise to the Atkin's-type extreme low-carb diet is a 'low glycemic' diet. Most low glycemic diets do not promote taking all carbs out of your diet. Instead it promotes sticking to those 'good' carbs that do not 'spike' the blood sugar. White flour, starch and sugar are considered high glycemic index foods. Eating high glycemic index food tends to cause the body to produce large amounts of insulin quickly when eaten. Low glycemic index foods like those from whole grains are harder to digest. Since the body digests these foods more slowly, they do not cause the rapid spike in blood sugar and therefore don't cause a rapid, profound insulin response either. This is thought to keep downregulation from happening.

Low-glycemic diets are being studied to see if they can help with weigh loss while not compromising nutrition. A good low glycemic diet will low in saturated fat, high in lean protein, have lots of healthy fruits and veggies and be high in fiber and whole grains. The Mediteranean diet is a good place to start when looking at different low glycemic diets. There is no one Mediteranean diet. Many  Mediterrean countries have variations on this type of eating. The Mediteranean diet typically has all of the good characteristics mentioned above and stresses good fats like those from olive oil and fish. It also is high in flavanoids and antioxidants like those found in red wine. It may have a slightly higher percentage of calories from fat than other diets, however, the majority of these fats are 'good' fats from fish and olive oil that have been shown to have beneficial effects on our hearts.

What About Low Fat Diets?

Low fat diets are ok as long as they specify where your carbs some from. Beware of doctors or nutritionists who stress a low-fat ADA pyramid diet that does not tell you what kind of carbs to eat. The idea of 'a carb is a carb' is an 'old school' way of thinking about nutrition. More and more evidence is mounting that tells us that we need to distinguish between starchy, sugary, nutritionally-void carbs and those with nutritional and metabolic value like those from whole grains. In other words 'calories in do not always equal calories out'. The body is a little more complex than that.

The Bottom Line

An extreme low-carb diet like the one promoted in the Atkin's Diet are not recommended. On the flip side, beware of traditional low-fat diets that promote starchy or sugary carbs. Instead, you may want to opt for a diet high in whole grain carbs, fruits, veggies and lean protein. A good diet should also avoid saturated fat and concentrate on getting most of its fat-calories from 'good' fats like those found in fish and olive oil. When you start eating well, you will be amazed how much better you feel and how much easier it will be to control your weight.