Publishing their findings in this week's issue of Archives of Internal Medicine, researchers at the University of Arkansas for Medical Sciences in the US say they found that a high carbohydrate diet consumed at will, with no attempt at energy restriction or change in energy intake, can result in the loss of body weight and body fat in older men and women.
The scientists examined the effect of a 12-week low-fat, high-complex carbohydrate diet alone and in combination with aerobic exercise training on body weight and composition in 34 individuals with impaired glucose tolerance in total 20 women and 14 men with a mean age of 66 years.
Participants were randomly assigned different diets. The control diet (41 per cent fat, 14 per cent protein, 45 per cent carbohydrate and 7 g of fibre per 1000 kcal) included foods such as sausage, scrambled eggs, macaroni and cheese, french fries, whole milk and some fruits and vegetables.
The high complex-carbohydrate diet (18 per cent fat, 19 per cent protein, 63 per cent carbohydrates and 26 g of fibre per 1000 kcal) included high-fibre cereal, vegetarian chilli, whole-wheat spaghetti, skimmed milk, and fruits and vegetables.
The third was a high-complex carbohydrate diet plus endurance exercise 4 days a week, 45 minutes per day at 80 per cent peak oxygen consumption. The researchers provided the participants with 150 per cent of estimated energy needs and instructed to consume food at will. Total food intake, body composition, resting metabolic rate, and substrate oxidation were measured.
The researchers conclude that despite the fact there was no significant difference in total food intake among the three groups and no change in energy intake over time, the high-carbohydrate diet participants with and without exercise lost more body weight and a higher percentage of body fat than the controls.
With more than 40 million Americans hitched on the Atkins diet, mainstream supermarket shelves are now heavy with the weight of low-carb alternatives supplied by food and drink manufacturers eager to cash in on the popularity of the 30 year old dietary regime. While the UK is showing signs of Atkins fever, a recent survey suggested that around 3 million people have given it a whirl, elsewhere in Europe consumers have been reticent.
Industry observers predict that an alternative diet trend - the Glycemic Index (or GI) labelling - that measures the effect that carbohydrates have on blood glucose levels, could offer greater possiblilities for European businesses.
Full findings for the recent high carbohydrated study, 'Effects of an ad libitum low-fat, high-carbohydrate diet on body weight, body composition, and fat distribution in older men and women,' by N. P. Hays, R. D. Starling, X. Liu, D. H. Sullivan, T. A. Trappe, J. D. Fluckly and W. J. Evans was published in Archives of Internal Medicine (2004) 164:210-217.