Low-carb diets not suitable for most people
18 April 2003
Low-carbohydrate, high-protein diets are inappropriate for most people who consult their doctor about their wish to lose weight, a leading Australian obesity researcher says in light of a recent review.
Dr Cameron-Smith, senior lecturer at Deakin University's school of health sciences, was commenting on a review showing there was not enough evidence to recommend such diets to anyone with risk factors for syndrome X.
(Syndrome X is not a disease in itself but a group of conditions that occurs at the same time, including obesity, high blood pressure, high blood triglycerides (type of fat), low levels of HDL ('good') cholesterol and insulin resistance. It is associated with a greater risk of certain other conditions such as diabetes and heart disease.)
'There would be few people approaching a GP for weight loss intervention who do not have significant cardiovascular disease risk factors, impaired glucose tolerance or diabetes. In these people, there is no evidence that high-protein diets are an appropriate strategy.'
However, for otherwise healthy individuals, the evidence indicated that a high-protein diet followed for up to 3 months would be relatively benign, provided there was some carbohydrate intake.
US authors of a systematic review of 107 articles covering more than 3000 patients concluded that low-carbohydrate diets resulted in weight loss due mostly to restricted calorie intake and long diet duration rather than reduced carbohydrate content (Journal of the American Medical Association 2003; 289: 1837-50).
There was insufficient evidence to recommend low-carbohydrate diets, particularly for longer than 90 days, the researchers said. They had not been adequately evaluated for the over 50s, or for those with high blood fat levels, high blood pressure or diabetes, they added.
Dr Cameron-Smith said the studies were flawed because of ineffective randomisation, short-term nature and the absence of strategies to address activity and emotional and behavioural factors.
'And we know that people can't stick to high-protein diets,' he said.
Concerns about the Atkins diet and similar regimes popularised by best-selling books included epidemiological (population health) evidence that high protein intake was associated with low bone mineral density.
In addition, little attention was paid to the type of dietary fat consumed, or to the consequences of reducing fruit and vegetable consumption.
Last Reviewed: 17 April 2003
- 1. Medical Observer Weekly 18/4/03
