An interview with Professor Katherine Appleton and Dr Lucy Boxall, Bournemouth University, UK
Dietary recommendations around the world consistently call for a reduction in high free sugars intake. However, effective strategies to achieve such a dietary change are yet to be defined. With this scope, a newly published randomised controlled trial evaluated the effectiveness of three different types of dietary recommendations in achieving free sugars intake reduction, and further evaluated their impact on diet composition and weight-related outcomes over a period of twelve weeks.
In this interview, we asked the principle investigator of this study, Prof. Katherine Appleton, Professor of Psychology at Bournemouth University, UK, and the PhD researcher Lucy Boxall, about the findings and importance of their study from both a scientific and public health perspective.
ISA: What was your new study about?
Prof. Katherine Appleton: A number of previous studies have used different methods to try to reduce free sugar intakes, and in our study we simply wanted to compare three of these methods. The participants of our study were given either nutrient-based information about free sugars (group N), or they were given this information, plus information on the foods high in free sugars (group NF), or they were given this information, plus further information on possible food substitutions (group NFS). All recommendations were based on the information available from the UK government, that was given at a single time point, and participants then recorded their diets for us, completed some questionnaires and were weighed and measured over the next 12 weeks. A control group also recorded their diets for us, completed the questionnaires and were weighed and measured, but they received no information. We were interested in the effects of the different types of dietary information on free sugar intakes, other aspects of the diet and on body weight. Approximately 60 people were recruited to each of the study groups, without any choice of the group they were given.
ISA: How did the different types of dietary recommendations affect the participants’ intake of free sugars and their overall dietary quality?
Lucy Boxall: On average, participants in the three groups that received the information reduced their free sugar intakes from around 10% of their total energy intake, to around 7% total energy intake, while those in the control group reduced their free sugar intakes to only around 9%. In other aspects of their diet, we found no effects in the consumption of specific foods, but energy consumed from other carbohydrates also went down, while energy consumed from protein went up. Importantly, fat intake and salt intake did not appear to increase.
ISA: How did the different interventions impact participants’ body weight?
Lucy Boxall: We found lower body weight at 12 weeks in the three groups with the dietary advice, when taking account of participant body weight at the start of the study. These changes demonstrated an average of around a 1 kg reduction in body weight in all groups compared to a reduction of 0.2kg in the control group.
ISA: Was any of the dietary recommendation versions easier to follow?
Lucy Boxall: As part of the trial, we also measured what participants thought of the guidance they were given and how they experienced the ups and downs of the 12-week period. These data are currently being written up for publication and will hopefully be available soon.
ISA: What is the significance of your study findings from a public health perspective?
Prof. Katherine Appleton: Our findings suggest that the current guidance provided by the UK government can aid individuals to reduce their free sugar intakes, to result in diets that are more healthy. Other dietary improvements were also found, and we found no increases in fat or salt intakes. Effects were achieved furthermore after only 1 week and lasted for the whole of the 12-week study period. It is important to add however, that our participants were all volunteers and were motivated to change their diet as part of the study. This motivation will have contributed to our findings. We also found no differences between the different types of information provided, and no differences between groups in the consumption of specific food items. These findings suggest that participants made small and varied changes to their diets, that when deconstructed into nutrients demonstrated a healthier diet, and may suggest value to providing individuals with a range of options and free choice when they asked to change their intakes.
ISA: Based on the study findings and the collective literature, what role could low/no calorie sweeteners play in recommendations for reducing free sugars intake?
Prof. Katherine Appleton: One of these options could be use of low-calorie-sweeteners. We find no specific effects of the advice including reference to low-calorie sweeteners, nor did we find effects in low-calorie-sweetened food consumption, but low-calorie sweeteners can provide a sweet taste in the absence of sugar, and may allow participants to maintain a palatable diet, that may otherwise be difficult to follow. Further work in this area is currently ongoing.
