This cluster randomized trial aims to test nutritional and physical activity interventions in older adults in nursing homes. The overall research question are:

o What are the effects of nutritional and physical activity interventions on muscle function and quality of life in older adults with overweight and obesity? Participants' data on body composition, physical function, and diseases will be collected. Furthermore, participants will be interviewed for a questionnaire on quality of life and nutritional intake.

Researchers will compare three intervention nursing homes with three control nursing homes to see if nutrition and physical interventions have on physical function and quality of life.

Background: The aging population is increasing both globally and nationally in Denmark. Concurrent with the generally rapidly increasing incidence of being overweight, a large number of older people risk facing several health problems associated with being overweight and obesity (Ow/O). Aging related to malnutrition or undernutrition has received a lot of attention. However, overnutrition described as Ow/O is also classified as a nutritional disorder or a nutrition-related condition, in the same term as malnutrition.

Today, all older adults in Danish nursing homes are offered an enriched diet type for malnourished older adults, focused on energy-dense snacks and a high-fat percentage. This is not necessarily an appropriate diet, but it is unknown which nutritional interventions are effective in maintaining/ improving physical functioning, independence, and quality of life. One of the concerns is that many older adults with Ow/O may have a loss of muscle mass, which can worsen with weight loss if this is not taken into account in the nutritional intervention. There is therefore a clear need to develop targeted interventions for older adults with Ow/O that can maintain or improve physical functioning and quality of life.

However, a literature review of interventions within the last 10 years shows that none of the interventions are aimed at healthy older adults ≥ 65 years with a BMI≥ 25kg/m2 and good physical functioning. Instead, interventions targeted older adults with Ow/O with either low physical functioning or chronic diseases. These interventions show that older adults can lose weight, but without significant positive effects on functioning and quality of life. The interventions in the studies contain complex nutrition and exercise interventions, and the differences in the intervention descriptions and target groups make it difficult to compare and point to safe and effective interventions. In addition, the studies show that there is no difference between whether the nutrition intervention applies to weight loss or weight maintenance interventions.

However, the above literature review has confirmed that there are older people with Ow/O, especially those with both low physical function and chronic disease, who may benefit from a nutritional intervention, which has led to a proposed approach. The characterization according to the screening model will be performed in sub-study 1 (a cross-sectional study) and adapted to be easy to use in a community health care setting.

In this trial, based on a descriptive pre-study, the project, in collaboration with the older adults, the care staff, and the project participants, developed and tested nutritional interventions that can improve muscle function and quality of life of the target group.

Purpose: The overall purpose is to investigate how muscle function and care-related quality of life can be maintained or improved through nutrition and physical activity interventions in older adults in nursing homes.

Study design and methods:

This cluster randomized controlled intervention study will be performed at six nursing homes in "Odsherred" City, Denmark. Participants and care staff from nursing homes will contribute to the design of this study protocol.

Sample size calculation:

Initially, the power calculation is performed by individual randomization based on the 30-second chair stand test. The starting point is six nursing homes are involved in the study. Approximately 40-50 residents are living in each location and assumable half of them want to participate in the project (n=20). A desired detectable change of 1.3, a P-value <0.05, and a power of 80%. The study has two arms (Usual care group (control) and nutritional and physical interventions group (intervention)) and the standardized difference in the nursing homes incl. intra cluster correlation, SD diff, nursing center = 0.42.

SD (diff., nursing center) =(SD (diff.,person))/√n, SD diff, person ≈1.87 If SD is 1.87 or less, the power will be at least 80% or greater. If there are more than 20 people per nursing home power will increase and if there are fewer than 20 people power will decrease.

Approximately 100 participants will be included and cluster randomized to either 12 months of collaborating developing (6 months) and testing (additional 6 months) nutritional and physical activity intervention (intervention group) or 12 months of usual care (control group). A simple random sample without replacement will be selected using the lottery method by statistical software (R).

Effects from the intervention will be examined by mixed methods that include both quantitative and qualitative data, as well as action research that focuses on creating development and change in collaboration with participants and care staff at the nursing homes.

Recruitment of participants and informed consent:

Recruitment of project participants takes place from "Odsherred" city's six nursing homes. The first step in recruitment takes place by the principal investigator orally and in writing informing the nursing homes, care staff, relatives, nursing home councils, and the residents of the nursing homes about the project's purpose, content, and course. In the next step, (oral information) the principal investigator, the care staff, and relatives talk to the residents. Participant information (written information) is provided. The written information contains a description of the project, its purpose, method, and possible consequences associated with the participant's participation.

In the trial, no serious adverse events or minor risks are expected. No biological materials are collected. A nurse at each of the nursing homes is included in the project and will be present during all data collection periods. The nurses will be involved immediately if any health issues or concerns about health issues should arise. This project meets the guidelines of the Declaration of Helsinki II, as well as the guidelines of the Regional Ethics Committee (EMN-2021-07672 ) and the University of Copenhagen Ethical Committee (504-0316/22-5000).

Participants have the opportunity to withdraw consent at any time during the project. If there are measurements, eg performance tests, which the participants do not want to participate in, available data is collected from the journaling system without participation in all measurements.

Data on participants who withdraw will be documented. Participants receive no fee or other benefits. Collection, storage, and processing of empirical data are done with the Danish Data Protection Agency's instructions for handling confidential information in research work of an empirical nature.

Nutritional and physical intervention:

The intervention is developed with a focus on nutritional needs and physical activities.

The Plan-Do-Study-Act (PDSA) model is used to redefine issues and relevant actions together with residents, care staff, nursing home management, and relatives. The intervention will be developed based on new knowledge from a descriptive pre-study, previous studies, practical experiences, the participant's experiences and wishes as well as the staff's experiences and wishes. In collaboration they will form an implementation catalog, from here, the nursing homes can select a relevant number of components, which will be tested and implemented in practice.

The development and implementation duration is 6 months and the PDSA model is repeated three times at two-month intervals to strengthen and qualify the intervention. The PDSA model is known to the city's staff in advance and is additionally used in connection to continuing education. In addition, everyday physical activities that contribute to maintaining/improving physical function are included, based on the potentials that are uncovered in the descriptive pre-study.

The development and implementation period was followed by testing the effects of the intervention components and 12 months follow-up data collection was performed.

Data collection:

Data are collected at baseline, after 6, and 12 months.

The primary outcome is sustained or improved muscle function, but other outcomes including the "Adult Social Care Outcomes Toolkit" (ASCOT) questionnaire, calf circumference, and nutritional risk using the Eating Validation Scheme (EVS) were also collected.

The data analysis takes into account that not all participants are included in all measurements.

Statistical analysis:

The analysis includes all data after randomization, regardless of non-compliance or lack of results.

The effect of measures and intervention is assessed using an analysis of covariates adjusted for potential confounders (sex and age), which will be used to compare the variables between groups.

The Fisher Xact Test or chi-square test will be used to compare groups of older adults with overnutrition in terms of body composition, muscle function, non-communicable disease, and nutritional risk.

Data on recruitment and participants' feasibility and compliance in relation to intervention will be assessed by descriptive and comparative analysis.

A statistical software program for scientific research "R" will be used for statistical analysis.

Inclusion Criteria:

• Living at the nursing homes in Odsherred City
• Informed consent form signed after receiving oral and written information
• Read, speak and understand Danish

Exclusion Criteria:

• Terminal ill

After study is finished, no data will be shared