Most people today have heard of Low Carb Diets. Typically, the diet restricts the intake of carbohydrates to below 20 percent of daily caloric intake. Most calories consumed come from proteins and fats. It is generally believed that The Atkins Diet released in the early 1990s marked the beginning of low carb diets. However the book Eat Fat and Grow Slim by Richard Mackarness was written in 1958 and also instructs dieters to cut their carbohydrate intake to almost zero.

The Atkins Dietis the diet that made low carb popular as it was sold to celebrities. It became more and more popular with every new celebrity who spruiked its benefits. These days there are many varieties on The Atkins Diet but all have the same thing in common - an extremely low intake of carbohydrates.

An Australian study published in Archives of Internal Medicine, a journal of the American Medical Association, has found that low carb diets, compared with low fat diets, can cause depression, anxiety and mood swings.

The study followed 106 overweight and obese dieters over twelve months, half on a low carb diet and the other half on a low fat diet. The low carb diet consisted of 4 per cent carbohydrate, 35 per cent protein and 61 per cent fat, and the high carb diet had 46 per cent carbohydrate, 24 per cent protein and 30 per cent fat. Each group was allowed the same number of calories per day, about 1,400 for women and 1,700 for men.

Both groups showed the same amount of weight loss of about 14kg, as well as similar effects on cognitive functioning (working memory and speed of processing information). Also, during the first eight weeks of the diet both groups showed a similar effect of elevated mood - they were happy with the results of beginning to lose weight. However as the diet continued and for the remainder of the year, those on the low carb diet started suffering from mood swings, anxiety, tension and depression.

The main points made by the researchers are:

• Low carb diets may have a detrimental effect on mood, negating any positive effect the weight loss may have.
• Carbohydrates are essential to proper brain functioning. Taking most carbohydrates out of the diet can cause depression and lack of stamina.
• Other studies have shown that taking carbohydrates out of the diet adversely effects brain functioning leading to chronic fatigue syndrome, mixed anxiety, restlessness, palpitations and panic attacks.
• The one situation where a low carb diet may be effective under strict supervision is in the case of diabetics. A low carbohydrate intake has been shown to be helpful in the management of diabetes, however further studies are required to see whether the changes in mood negate any improvement from the low carb intake.

Other studies have also found that very low carb diets may help in the management of epilepsy.

I am by far no expert in Low Carb Diets. As a teenager many years ago I read Eat Fat and Grow Slim, but couldn't follow the diet as I simply love my carbohydrate foods too much. I found that reducing my fat intake, consuming low GI foods and increasing my exercise levels worked wonderfully to lose weight and feel energetic.

I know everyone's experience will be different so I would never totally discount anything that seems to be working. I only hope that weight loss doesn't come at the expense of a person's good health and wellbeing.

The main things about low carb diets that make me think they're not a healthy option are:

• As mentioned above, the brain needs glucose (a simple carbohydrate) to function properly. It uses glucose exclusively as its energy source. Without sufficient fuel, the brain cannot function properly. I have experienced hypoglycemia (low blood sugar levels) and know that it can result in lower levels of concentration, dizziness, and even unconsciousness.
• Dietary fibre is only found in carbohydrate-based foods. Both soluble and insoluble fibre is necessary to good health. Although fibre can be taken in tablet form or as a drink, I have found that these forms of fibre are not always as effective as obtaining fibre from fibre-rich food sources.
• Low carb diets are high in protein and fat. This could result in a high intake of saturated fat which can lead to high levels of cholesterol.
• Ketosis - this is when the body has run out of carbohydrate stores and starts converting fats into fatty acids and ketone bodies to use as an alternative source of fuel. This may sound good at first, after all isn't that what we want, for our fat stores to be converted and used as energy? However changing fuel sources from predominantly carbohydrates to fats is a complex process and takes various stages to complete. The adverse health effects have been argued but are not conclusive. Different groups also argue on one side that this is an unnatural state, while the other side argues that historically many groups have (and still do) lived on such diets. Personally I feel as though it's an unnatural state for our bodies to be in because of the above three points, but I know others feel differently about this.
• Bad breath - once in a state of ketosis, ketones are released from the body in the breath and in the urine. Ketones on the breath cause a foul odour and many people on long term low carb diets have to counteract this with oral sprays.