By Carley Rusch

The number is startling--51% of the world’s population will have overweight or obesity by 2035, according to the World Obesity Atlas 2023. As the ICAA commented earlier this year, this was presented to the United Nations by the World Obesity Federation, which also called on governments to develop national action plans to address obesity.

According to the same report, one of the top perceived barriers to effective treatment is that “obesity [is] not recognized as a disease.” Obesity is defined by the Obesity Society as a chronic disease that increases risk of other conditions, such as cardiovascular disease, cancer, and diabetes, and is associated with premature mortality. Obesity treatments can include lifestyle and diet modifications, medications, and/or surgical interventions to induce changes in body weight and reduce complications.

Traditionally, body mass index (BMI) has been the focus for identification and treatment of obesity. The American Association for Clinical Endocrinology (AACE) has recently introduced a new diagnostic term, adiposity-based chronic disease (ABCD), to shift from a weight/BMI-centered obesity diagnosis to an approach that aims to improve health through prevention and treatment of complications (see below).

AACE Complications-Centric Care Model for Adiposity-based Chronic Disease (ABCD)

Abbreviations: AACE, American Association of Clinical Endocrinology; ABCD, adiposity-based chronic disease; BMI, body mass index.

Weight Loss and Body Composition Changes

Weight loss may be a part of the treatment plan for older adults with obesity and/or ABCD complications. AACE recommends weight loss between 5-15% to improve ABCD complications. Yet some individuals with more severe ABCD complications may benefit from more weight loss. Medications, such as semaglutide and tirzepatide, have been approved for the treatment of obesity. In combination with intensive lifestyle interventions, these medications can induce significant weight loss (i.e., >10% within 6 months). Intensive lifestyle interventions usually focus on achieving a calorie deficit to assist in weight loss and use a holistic approach to improve nutrition, physical activity, sleep, and mental health. 

Rapid weight loss while taking medications for obesity induce significant changes in body composition, including variable losses in muscle. Skeletal muscle supports body strength, movement, and balance. It is also an essential organ for insulin sensitivity, protein and glycogen storage, and immune function. Loss of muscle can be a sign of malnutrition and sarcopenia which are conditions that can increase risk for falls, reduced strength, and quality of life. 

Preserving muscle during intentional weight loss is important for active aging but can be impacted by age and chronic disease. Adults naturally lose between 3-8% of their body’s muscle with each decade of life. Obesity and diabetes may further contribute to loss in muscle vitality, as older adults (aged 65+) with these conditions can have two-fold greater loss of muscle compared to adults without diabetes.

Protein is Needed to Maintain Muscle

Protein is an important macronutrient, providing amino acids which are the building blocks for maintaining muscle, providing energy, and forming proteins needed for metabolism. While the Recommended Dietary Allowance (RDA) for protein in adults is 0.8 g/kg body weight/day, older adults may require up to 1.2 g/kg body weight daily to build and preserve muscle. It is reported nearly half of older adults (ages >50 years old)  do not meet the RDA for protein and are also more likely to have reduced intake of other nutrients. This may be the result of changes associated with aging including taste, poor oral health, delayed stomach emptying, mood-related shifts and other changes.

To promote healthy weight loss and maintain muscle, it is crucial to monitor and maintain adequate protein intake for older adults who pursue weight loss through various strategies including obesity medications. In combination with resistance exercise, increasing protein intake — especially at breakfast and lunch — to achieve an even distribution of protein throughout the day may be necessary to support muscle. While meeting nutritional needs through foods alone may be difficult, oral nutrition supplements can be helpful to support the nutrition needs of patients pursuing intentional weight loss. In addition, older adults on obesity treatment medications could seek the support of a registered dietitian nutritionist who can help monitor protein intake and provide individualized diet recommendations. In summary, these recommendations are important to help maintain the muscle needed to support active aging during obesity treatment.

Resources:

• The Academy of Nutrition and Dietetics position paper on Weight Management for Adults provides information for healthcare professionals about interventions for the treatment of overweight and obesity in adults.
• The STOP Obesity Alliance Weight Can’t Wait guide providers guidance for healthcare professionals on the management of obesity in the primary care setting
• The Intentional Weight Loss in Older Adults and Motivational Interviewing webinars review effective strategies associated with weight loss in adults.

Carley Rusch, PhD, RDN, LDN is a medical science liaison for the Nutrition division of Abbott, located in Columbus, Ohio.