Risk of weight gain due to the consumption of ultra-processed foods or Cystic Fibrosis Transmembrane Conductance Regulator modulator intake: Studies on the impact of protein content in ultra-processed foods and an inpatient rehabilitation programme in people with Cystic Fibrosis

Abstract

This doctoral thesis explores two critical risk factors for obesity: the consumption of ultra-processed foods (UPF) and the use of a novel pharmacological therapy in people with Cystic Fibrosis (CF). Strategies to address these risks include protein fortification of UPF and rehabilitation programmes combining exercise and dietary counselling for people with CF, who often have poor diet quality. The low protein content of UPF may contribute to increased energy intake, as humans overconsume low-protein foods to meet protein targets (protein leverage). The first study presents a market analysis of high-protein (HP) UPF in German supermarkets and online shops, assessing nutritional value, additives, and hyper-palatability. HP UPF had an improved nutritional profile with lower energy density, sugar and fat content, higher fibre and protein content, but more additives and higher salt content. The use of flavourings and artificial sweeteners in HP UPF may increase palatability and promote hedonic eating and excessive intake. Thus, protein fortification in UPF may not effectively reduce the risk of weight gain. Long-term studies are needed to assess their impact on energy balance and health. The second study examines the impact of CFTR modulator therapy (ETI: Elexacaftor, Tezacaftor, Ivacaftor) on appetite regulation and energy balance during a 3-week inpatient rehabilitation programme with exercise. ETI patients had higher post-exercise meal intake, but changes in BMI and body composition were comparable to those without ETI, likely due to the higher prevalence of pancreatic insufficiency. These findings imply that rehabilitation programmes with regular exercise may improve body composition in people with CF on ETI therapy without leading to a more positive energy balance. Given links between ETI intake and fat mass gain, rehabilitation programmes should prioritise improving body composition and reduce UPF consumption to support long-term metabolic health