Participants
Objectives
Brochure

RTD1: Obesity and macronutrient composition of the diet
Co-ordinator: Professor Arne Astrup, Copenhagen, Denmark

The macronutrient composition of the diet appears to play a role in determining the total energy intake. Proteins have been shown to produce a higher degree of satiety and to have a higher stimulating effect on energy expenditure compared with fat and carbohydrates.
In addition carbohydrates with a low glycaemic index (GI) have been suggested to have a higher satiating power than carbohydrates having a high GI. However, so far this evidence, which has led to some widely promoted dietary recommendations, has come only from studies limited in duration, subject numbers and types, and dietary variables.
The core of RTD1 will be a 6-12 months dietary intervention study involving some 350 families (obese/overweight parents and their children) across 8 European centres. All adults will complete an 8-week weight loss phase with a fixed low energy intake. Hereafter the families will be randomised to one of 5 diet groups differing in carbohydrate GI and protein content. The aim of this controlled intervention study is to address the efficacy of these diets in preventing weight (re)gain. The intervention study will also generate information and materials for RTDs 2, 3 and 4, and may test new food concepts from RTD5.
 

RTD2: Obesity and gene-nutrient interaction
Co-ordinator: Dr. Dominique Langin, Toulouse, France

The model for obesity is a two-step one: an individual’s susceptibility is determined largely by genetics, while the observed outcome is determined by environmental factors (diet, physical activity etc.). Understanding of the genetic elements is still limited. We have not identified the multiple genetic determinants of excess fat mass, and knowledge of the interactions of gene function and nutritional status is scarce.
Diogenes will focus on gene-nutrient interactions associated with changes in body weight. RTD2 will identify and characterise biomarkers of dietary intake with variations in GI and protein content and predictors of weight- and metabolic variations. Three complementary, state-of-the-art approaches will be used:
• genetics, addressing how variants in the coding and the regulatory regions of candidate genes affect overall weight regulation, and whether certain genotypes are associated with a differential response to different dietary GI levels or protein content respectively.
• transcriptomics, addressing whether gene expression in adipose tissue predicts weight loss and weight gain patterns, and how gene expression is altered in response to changing the dietary protein content or GI.
• proteomics/peptidomics, addressing whether proteins or peptides in the blood predict weight loss and weight gain patterns, whether some peptides predict a differential response to different diet compositions, and finally how protein and peptide levels alter in response to changing the dietary protein content or GI.
Input samples and phenotypic data (weight and metabolic variables) will be drawn from the RTD1 intervention study and RTD3 epidemiology cohorts, and findings validated in the intervention study population.


RTD3: Obesity, genes and diet at the population level
Co-ordinator: Professor Thorkild Sørensen, Copenhagen, Denmark

There is strong evidence that environmental factors in general influence the differences in occurrence of obesity both within and between populations, but we do not have a clear and coherent understanding of those factors. One major reason is that weight gain in any single individual is influenced by multiple, interacting, influences, including socio-economic and psycho-social background, life events and life-style, physical activity and diet. For example, there is no clear-cut evidence from prospective population studies pointing to specific dietary components as major factors in obesity development.
Diogenes’ RTD3 will use epidemiology to study the long-term role of key dietary parameters – carbohydrate GI and protein content – in relation to other behavioural, environmental and genetic factors, in influencing obesity and its co-morbidities in the general population across Europe. The studies will draw their data from pre-existing cohorts, including 145,000 subjects followed for up to 5 years in the EPIC cohorts (see www.iarc.fr/epic/) and two twin cohorts in Finland and Denmark. Data from analyses of these cohorts will link with the studies of the RTDs 1 (macronutrient composition), 2 (genetic factors) and 4 (psycho-social factors).


RTD4: Obesity and consumer attitudes and behaviour
Co-ordinator: Dr. Monique Raats, Guilford, United Kingdom

Availability of foods and dietary advice which can facilitate weight control is no guarantee that individuals will successfully control their weight. The majority of individuals who lose weight by dietary adjustment cannot control or sustain the loss. It is clear that in choosing dietary approaches, consumers are influenced by other major factors: their lifestyles, their psychological, psycho-social and physiological characteristics, and their own behaviour patterns. If weight control strategies through diet, such as change in GI and protein content, are to succeed, they need to be complemented by advances in understanding the roles of these factors. New dietary solutions can then be tailored to fit with the consumer’s attitudes, perceptions and difficulties with effective weight control.
RTD4 will develop a series of psychological/behavioural predictors of weight control or gain, which will be validated in the intervention study (RTD1). These predictors will then be integrated with biomarkers (RTD2) and actual responses to diet composition (RTD1) in a new Obesity Risk and Behaviour Advice Screening Tool (ORBAST). ORBAST is a software-based tool to assist consumers in devising, and their health professionals in prescribing, individual behavioural approaches to weight control that better protect against obesity.


RTD5: Obesity and food technology
Coordinator: Dr Øydis Ueland, Oslo, Norway

The sensory experiences of eating determine to a great extent both the foods we choose and how much we eat of them. Diogenes will explore the potential to develop foods that combine liking with limitation of intake due to enhanced satiation signals. RTD5 will bring together
• sensory, metabolic and psychological studies to identify physiological, oral or olfactory triggers which regulate food intake behaviour
• development and testing, including in the dietary intervention study of RTD1, of concept foods which incorporate triggers to regulate intake, as well as varying values for GI and protein content.
Findings on variations in the sensory status of consumers in relation to food intake control will be an additional input to the ORBAST of RTD4.


RTD6: Data Hub
Co-ordinator: Dr Claus Holst, Copenhagen, Denmark

The central data hub will maximize integration between RTD lines, through standardization of protocols and data collation, the storage of (or remote access to) data from the RTD lines, and rapid, detailed analysis and modelling of complex data sets.
Shared tasks, common protocols and objectives will all be orchestrated through the links between the data hub, the Diogenes website and the NuGo Network of Excellence with which Diogenes will be associated. This will ensure frequent cross-fertilization and exchange of innovative ideas between the consortium and other institutions/organisations, drawing benefit from the scientific critical mass and capabilities involved.
 

RTD7: DIDT. Ensuring Diogenes’ science yields practical benefits
Co-ordinator: Gabby Hul, MSc and Karin Quanten, Maastricht, the Netherlands

The ultimate aim of Diogenes is not only the new scientific knowledge it will generate. It is the widespread application of that knowledge for the benefit of people who might otherwise be overweight or obese.
In DIDT, Dissemination activities will communicate with key stakeholder groups who can influence public awareness of obesity and its associated risks, and create a climate supporting new strategies for combating obesity.
Innovation (including demonstration) will be a programme of activities designed to secure the transfer of exploitable knowledge from RTDs 1-5 to SMEs, the food industry and service providers in the area of health and diet, so that commercialisation in beneficial new products and services occurs as rapidly and widely as possible.
Training will ensure that the specialist skills necessary for execution of the Diogenes programmes are embedded in the institutes and the persons who will be required to practice them. Externally it will disseminate these skills to others in the broader scientific community to benefit their research capabilities and professional development.