The Effects of Ready Meal Consumption on Self- reported Appetite Ratings and Subsequent Food Intake in Females

Introduction: Overweight and obesity are public health concerns and there is a forecast rise in the consumption of ready meals that are generally high in saturated fat and low in fibre (Reimers et al. 2011; WHO, 2018). Slimming World, a commercial weight management organisation has designed a range of ready meals in line with their weight management programme, which advocates an unrestricted intake of low energy dense food in order to aid in weight loss. Hence, it is valuable to understand the satiating properties of ready meals in order to establish if specific ready meals can enhance satiety and contribute to reducing subsequent energy intake. This thesis will explore the effect of ready meals on short-term satiety and food intake among females with a BMI ≥ 25 kg/m2. Methods: In two separate studies a total of 38 female participants (Study One: n= 26, Study Two: n= 12), aged between 18-65 years attended Oxford Brookes Centre for Health and Nutrition for two separate testing days. Study One aimed to investigate the effects of energy matched ready meals (calorie-matched but differing quantities of protein and fat), whilst Study Two aimed to explore the effects of fixed portion size (differing in calories and fat, with similar protein) ready meals on appetite and subsequent energy and macronutrient intake. The ready meals (Control = Sainsbury’s, Test = Slimming World) differed in energy density and macronutrient composition, with satiety responses investigated in the studies. For both studies, participants consumed a standard breakfast and four hours later consumed either a test ready meal (lasagne, higher energy density) or the control ready meal (lower energy density). Four hours after lunch participants food intake was measured during an ad libitum buffet tea. Additionally, satiety measurements were recorded using visual analogue scales throughout and participants completed a weighed food diary for the remainder of the test day. Results: Study One revealed that the test meal significantly reduced hunger (p= p<0.001), desire to eat (DTE; p<0.01) and prospective consumption (p=0.001), whilst fullness (p<0.001) increased compared to the control meal between lunch and the buffet tea. There was no significant difference between energy intake between the two ready meals during the buffet tea (p=0.10), however, during the whole testing day the test meal provided significantly less fat and saturated fat (both p<0.01), but significantly more carbohydrates, sugars, fibre, protein and salt (all p<0.01) compared to the control day. In Study Two, appetite ratings between lunch and buffet tea indicated no difference between the two meals for hunger (p=0.06) but fullness was significantly greater (p<0.01) after consuming the control meal. DTE and prospective consumption were significantly greater after consuming the test meal (p=0.01 & p=<0.01, respectively). Whole day food intake showed a significant reduction in energy intake (~873 kcal; p=0.05), fat and saturated fat (both p=0.00) for the test day but there were no differences between test and control days regarding carbohydrate, sugars, fibre, protein and salt (all p>0.05) consumption. Conclusion: Both of these studies found that in the instance of subsequent shortterm energy intake, there was no significant difference between the two ready meals, despite indicating beneficial subjective satiety responses. Nevertheless, these ready meals are important for aiming to improve nutritional guidelines e.g. reduced fat, especially if the forecast increase in ready meal consumption does occur. It may be beneficial for weight management organisations to continue to promote consumption of ‘satiety-enhancing’ ready meals over standard ready meals in order to lower fat, potentially impacting long-term energy balance and overall health but longitudinal studies would need to be conducted