New study challenges conventional thinking that high carbohydrate, low fat slimming plan should contain little or no added sugar (sucrose).
A team of scientists at Queen Margaret University, Edinburgh has found that a low-fat, high-carbohydrate diet (containing sucrose) combined with physical activity achieved the greatest health benefits in overweight subjects. The study, which will be published in the August issue of International Journal of Food Sciences and Nutrition, provides evidence that the exclusion of sucrose, as is normally advocated in a weight loss diet, is not necessary to achieve weight reduction. In fact, the palatability of sucrose may even help dieters stick to their eating plans.
As part of a 12-week programme, 69 overweight women (average age 41 years; average body mass index [BMI] 32 kg/m2) were given advice on either diet, physical activity or both. A fourth group acting as the 'control' received no advice. Measures of body fat and markers of heart disease risk (such as waist circumference and cholesterol levels) were collected at the beginning and end of the trial.
The advice followed healthy eating guidelines and recommended:
- a reduced daily calorie intake, which was low in fat (35% of calorie intake) and high in carbohydrates (55% of calorie intake)
- that one tenth of their total calorie intake included sugar - around the average for a British adult. To achieve this goal, subjects were advised to include high carbohydrate snacks such as low fat cereal bars and low fat yogurts (containing at least 20g sugar) between two and four times per day, depending on their energy needs.
- an increase in activity levels focused on including sixty minutes of brisk walking per day.
Writing in the International Journal of Food Sciences and Nutrition, the researchers noted that after three months, the group combining the sugar-containing diet and activity changes recorded the greatest positive health outcomes, compared with diet or exercise alone. Significant reductions were observed in body weight (4.7% loss), waist circumference and percentage body fat. Measures of blood fats (total cholesterol and LDL) had also significantly improved.
'This research contributes to the growing body of evidence that an effective way to lose weight is by adhering to a high-carbohydrate, low-fat diet and by being physically active.' commented Dr Drummond, adding ' it also provides evidence that the exclusion of sucrose, as is normally advocated in a weight loss diet, is not necessary to achieve weight reduction.'
Part of its effectiveness may be due to the palatability of sucrose, making it easier to stick to the diet. As Dr Drummond points out 'Compliance with this palatable low fat diet was excellent and when combined with increased physical activity resulted in significant improvements in body composition for this group of overweight women.' This study highlights the need for dietary advice to accompany increased physical activity in order to achieve weight loss. It also demonstrates that a low-fat, high-carbohydrate, sucrose-containing diet combined with increased exercise can be effective for slimming. Further studies are now required to investigate which methods will motivate overweight individuals to adopt these lifestyle changes.