Development of protocols to identify high hunger and low satiety phenotypes

Obesity has become a worldwide epidemic. Impaired appetite control is associated with weight gain. People who have difficulties in recognising their appetite sensations before and after a meal and who do not eat in response to their appetite sensations seem to be more susceptible to weight gain. These individuals may represent the ‘low satiety phenotype.’ The objective of the present study was to extend and test the work identified in the literature regarding the identification of a satiety phenotype. To identify, at baseline, individuals who struggle to lose weight on weight management programmes, due to reduced satiety, to help clinical professionals to identify those people at baseline so that they can use personalised weight loss strategies to help them. The work included studies in an acute laboratory setting and clinical studies. The first laboratory setting study was a pilot study to allow the researcher to gain expertise in the methods used to assess satiety phenotypes in people with obesity by analysing blood samples for gut hormone levels, subjective ratings of appetite response to a test meal, Three Factor Eating Questionnaire (TFEQ) subscales, food diaries and food craving. A second laboratory based study identified a satiety phenotype in individuals with normal weight by measuring energy intake in an ad libitum test meal, as well as energy intake from a 3 day food diary. Subjective ratings of appetite response, gut hormones, TFEQ and food cravings were also assessed. This study developed methods to subsequently use in a clinical community by designing a heat map, which is a visual presentation tool including independent variables, scores to help clinical professionals working in clinical settings to follow this scoring system to identify individuals who have low or high satiety prior to participation in weight management programmes. Clinical studies were carried out on individuals with obesity by determining at baseline, variables prior to participation in a weight management programme to identify those who struggle to lose weight. In the study carried out in a Tier 3 setting, fasting samples of plasma gut hormones, subjective ratings of appetite response and TFEQ subscales were used to predict subsequent weight loss and reduced satiety. In a Tier 2 setting study, food diaries, food craving and TFEQ subscales were used to identify those who may struggle to lose weight. In the acute laboratory setting, subjective ratings of appetite response were found to be the best measure to identify satiety phenotypes and this was combined with other predictive measures to build the heat maps. In the clinical studies, subjective ratings of appetite response were the best baseline measures to predict weight loss. In the Tier 3 study, subjective ratings of appetite response predicted weight loss and people with reduced satiety, as determined using the heat map tool, on average lost more body mass, BMI and waist circumference although the difference was not significant. In the Tier 2 study, carbohydrate food craving predicted subsequent weight loss. In conclusion, the novel findings in this study are the further development of protocols to identify high hunger and low satiety phenotypes. These will inform researchers and staff in clinical community settings to identify people who have a low satiety phenotype and may inform personalised treatments. However, further studies are needed with larger sample sizes to fully elucidate and validate the above findings.