During the research, male and female subjects consumed orange juice from concentrate, semi-skimmed milk, a sugar-sweetened fruit drink or a calorie-free fruit drink, one hour before their lunchtime meal. Each group was then provided with a self-selection buffet, including a variety of foods in ample quantity, and the amount of energy they then freely consumed was analyzed and compared.

The results show that liquid calories are detected by the body and compensated for at the next meal. Both men and women who consumed a drink containing calories in the morning ate less energy for lunch, compared to when they had a calorie-free mid-morning drink. However, while the mean total energy intakes for men following all four beverages were similar, women demonstrated a trend for greater energy intake following the three caloric drinks compared to the control. Thus, using a preload paradigm differing in protocol to previously reported studies, the new research gives evidence of a possible energy compensation dysregulation in women compared to men.

Professor Henry, of Oxford Brookes University, said, "It is important to understand if the growth in caloric beverage consumption is contributing to the increased prevalence of obesity and diabetes. It has been suggested that sugars provided in liquid form encourage 'passive over-consumption' of energy from food, but this study shows that the body does compensate in the short term. Further research is now needed to understand the mechanisms involved and whether the body also compensates for liquid calorie consumption in the long term."

From the September 20, 2010, Prepared Foods E-dition