Are low-carbohydrate diets the best way to lose weight?

Low-carbohydrate diets have become extremely popular, promoting quick and easy weight loss. However there is continuous debate over the benefits and safety of these diets.

PRINCIPLE

Low-carbohydrate diets generally aim to encourage the consumption of unrestricted amounts of protein-rich foods (meat, poultry, dairy, eggs), and limit or restrict the intake of carbohydrate-rich foods (bread, cereals, grains, pasta, fruit, vegetables).

The basic principle of any low-carbohydrate diet is that weight gain is caused by carbohydrate, hence the need to limit or restrict carbohydrate-containing foods. However, it must be emphasised that weight gain is the result of consuming too many kilojoules or calories (units of energy), in excess of how much energy the body is expending.

Also, according to these diets, if you eat lots of protein, the body reduces its production of insulin (a hormone that is stimulated by eating carbohydrates). Therefore without carbohydrate to burn, the body will be forced to use fat for energy or fuel, thus causing weight loss. However, weight loss through fat burning, in the absence of carbohydrate, will not in itself lead to weight loss unless people consume less energy than their body expends.

PROS AND CONS

• These diets, which promote an unrestricted protein and fat intake, and restricted carbohydrate intake:
  - Contradict the Dietary Guidelines; these Guidelines outline, based on scientific evidence, the best ways to achieve optimal health and nutrition.
  - By restricting the intake of carbohydrates, certain food groups (and therefore nutrients) are excluded from the diet, such as breads, cereals, grains, fruits and vegetables. As a result, people may miss out on getting all their essential vitamins and minerals.
  - Diets low in carbohydrate are also low in fibre, which is essential for intestinal health and prevention of certain cancers.
  - These diets do not provide the variety of foods needed to achieve a balanced diet, important for meeting nutritional needs.
• As promoted, many people on these diets lose large amounts of weight, rapidly. Initial weight loss on low-carbohydrate diets is mostly water and muscle loss, not body fat. If the diet is maintained for a reasonable time period, it does lead to meaningful weight loss in body weight and fat. However, when a ‘normal’ diet is resumed, i.e. when there is more carbohydrate in the diet, weight returns mostly in the form of fat. 
• A high protein and fat intake, especially saturated or ‘bad’ fat intake, have been associated with several long-term health risks and complications, including Heart Disease, kidney damage, osteoporosis, certain cancers, and other diet- or health-related problems.
•  There are several reported side-effects associated with low-carbohydrate diets, such as constipation, nausea, dizziness, dehydration and bad breath.
• Low-carbohydrate diets are often difficult to stick to, as the diet can become boring with being so rigid. People often increase their carbohydrate intake after a while, therefore making long-term weight loss and maintenance unsuccessful.

CONCLUSION

There are no quick, easy ways to lose weight and maintain it successfully over the long-term. There is potential for people to achieve weight loss on a low-carbohydrate diet, being suitable for some people over others. Ultimately, to achieve weight loss and avoid weight gain, energy intake (the calories or kilojoules you consume through food and drink) should not exceed energy expenditure (the energy your body uses in rest and during activity) over a period of time. For long-term weight management, the benefits of a healthy, well balanced diet and regular physical activity cannot be emphasised enough.