Inside UC Davis Health’s new approach to obesity care

Obesity has become a major public health crisis in the United States, leading to serious health consequences and placing a significant burden on the health care system. 

Currently, more than 40% of U.S. adults and one in five children are classified as being obese. This marks a dramatic increase from 1960, when fewer than 15% of adults were considered obese.

The economic impact is substantial. Obesity-related health care costs in the U.S. are estimated at $173 billion annually. On average, individuals with obesity incur $1,861 more in medical expenses each year compared to those with a healthy weight.

In response to this growing issue, UC Davis Health’s Division of Endocrinology is launching a new Obesity Clinic to provide specialized care for patients struggling with severe obesity. Miranda Stiewig-Rapp, a medical doctor and an endocrinologist who will be directing the program, joined us to share insights into the clinic’s goals. 

She discusses current trends in obesity treatment, including GLP-1 agonists, the potential benefits of intermittent fasting and the health care industry’s shift toward more personalized approaches to obesity care.

How have GLP-1 receptor agonists transformed the clinical approach to obesity management?

GLP-1 agonists are transforming the landscape of weight management by significantly enhancing the results we can achieve when combined with lifestyle interventions. Before their introduction, we relied on medications such as phentermine, dopamine agents, bupropion and naltrexone, which typically resulted in a 5-10% reduction in body weight. In contrast, GLP-1 agonists have demonstrated weight loss outcomes of approximately 15-20% in some cases. Even more promising results are emerging with tirzepatide, which shows potential for even greater efficacy.

What’s particularly exciting is that, when these medications are paired with lifestyle therapy, we’re not only helping patients reach their weight loss goals but also supporting long-term maintenance through continued treatment.

As these therapies become more advanced, we are now seeing the development of triple agonists that are producing even more substantial weight loss. These next-generation medications could offer a non-surgical alternative to bariatric procedures, which have traditionally been necessary for significant weight reduction. Over time, these medications may help patients avoid surgery altogether, along with the associated risks such as micronutrient deficiencies.

How do you integrate behavioral therapy, nutritional counseling and exercise physiology alongside pharmacologic treatment?

Obesity is a complex condition influenced by multiple factors, and it is essential to meet patients where they are. Because individuals may struggle with obesity for a variety of reasons, treatment must be personalized and comprehensive.

For some patients, addressing underlying mental health conditions such as depression or anxiety is critical, as these can limit their ability to engage in physical activity. Other patients may face physical limitations due to injury, making physical therapy an important tool for teaching safe, pain-free exercises that promote movement without causing discomfort. By addressing these barriers early, patients are more likely to engage with other lifestyle interventions.

Nutrition education is also important. Helping patients understand macronutrients, micronutrients and how to achieve a caloric deficit through counseling can significantly support their progress. Additionally, managing obesity-related comorbidities such as sleep apnea is vital. Connecting patients with sleep medicine specialists to improve sleep quality is crucial, as poor sleep can significantly hinder weight loss efforts.

Ultimately, a successful approach to obesity must be multifaceted. When our obesity clinic at UC Davis Health opens this fall, we will integrate nutrition, physical therapy, sleep medicine, behavioral counseling and medication management. This holistic model is designed to meet patients where they are and support them in achieving sustainable health goals.

“When our obesity clinic at UC Davis Health opens, we will integrate nutrition, physical therapy, sleep medicine, behavioral counseling and medication management. This holistic model is designed to meet patients where they are and support them in achieving sustainable health goals.”—Miranda Stiewig-Rapp

How reliable is BMI as a primary health metric and what alternative measures do you find more clinically meaningful?

We are moving away from relying solely on BMI because it does not accurately reflect body composition. BMI is calculated using weight and height, which means a patient with significantly more muscle mass, such as a bodybuilder, may fall into the overweight or obese category, even though they do not have increased metabolic risk factors due to low levels of adipose tissue.

In the field of obesity medicine, there is a growing emphasis on finding better ways to quantify adipose tissue relative to muscle mass and to stratify risk based on metabolic factors. One promising method is bioimpedance, which measures fat tissue, muscle mass, skeletal muscle, water weight and bone mass. It also differentiates between visceral and subcutaneous fat, which poses health risks, and essential fat that the body needs.

Tools like bioimpedance and DEXA scans allow us to better understand body composition and assess a patient's health more accurately. Tracking increases in muscle mass and decreases in adipose tissue can also be motivating for patients. Many become discouraged when the number on the scale does not change, so having alternative ways to demonstrate progress can be very encouraging.

What strategies can physicians employ to mitigate weight stigma in clinical environments?

Much of the stigma surrounding obesity stems from the belief that it is a moral failure or that patients have simply chosen a lifestyle that led to their condition. This perception can cause significant shame and make individuals feel as though they are at fault, which can be discouraging.

In reality, obesity is a multifactorial condition influenced by genetic, hormonal and environmental factors. For example, when someone loses weight, hormonal pathways involving ghrelin and leptin respond by increasing appetite to regain the lost weight. This is a primitive biological mechanism designed to protect against starvation and famine, which are no longer common threats in many modern societies. As a result, the body actively resists weight loss, making the process even more challenging and discouraging for patients.

Part of our role as clinicians is to help patients understand that obesity is not a moral failing. We must acknowledge the biological and hormonal factors at play and support patients as they navigate these challenges. It is also important to engage patients in their own care, empowering them to take an active role in their treatment and helping them feel in control of their health journey.

Do you consider intermittent fasting a first-line dietary intervention for patients with obesity, or do you reserve it for specific clinical scenarios?

I believe intermittent fasting should be reserved for more specific scenarios. Especially in the initial stages of obesity treatment, or for someone who has never engaged in lifestyle therapy. The focus should be on creating a caloric deficit while maintaining balanced nutrition. This includes ensuring adequate intake of protein, carbohydrates, healthy fats, minerals and micronutrients. Intermittent fasting may also not be the best choice for achieving a caloric deficit for patients with diabetes, due to risk of low blood sugar. 

Research has shown that intermittent fasting through time-restricted eating, or 24-hour fasts can lead to successful weight loss and improvements in other cardiometabolic risk factors. Recent studies have shown, however, that there is not a significant difference between intermittent fasting and simply reducing overall caloric intake through consistent meals throughout the day. Ultimately, it comes down to what a patient can realistically maintain. If a patient finds it easier to follow a 12-hour or 16-hour fast, or alternate between fasting and regular eating days, and can adhere to that approach, it can still result in a caloric deficit and lead to weight loss.

However, for many patients just beginning treatment, intermittent fasting may feel overwhelming. It is important to meet patients where they are and take gradual steps while ensuring they maintain good nutrition. If a patient has already received nutrition counseling and is consistently eating smaller, balanced meals and expresses interest in trying intermittent fasting, it may be a reasonable option.

At the end of the day, the goal is to help patients achieve and sustain a caloric deficit in a way that is manageable and supportive of their overall health.

Do you anticipate a shift toward personalized obesity treatment based on hormonal profiles, genetic markers or other biomarkers?

Monitoring markers of metabolic health is becoming increasingly important. We currently regularly monitor hemoglobin A1c, lipid profiles and liver function to assess the cardiometabolic impact of obesity. One area gaining attention is lipoprotein(a), or Lp(a), which is genetically determined and associated with increased cardiovascular risk. Although lifestyle changes do not affect Lp(a) levels, several promising therapies are currently in development to target and reduce these levels and thereby improve cardiovascular risk. As these treatments become available, routine monitoring of Lp(a) may play a larger role in cardiovascular risk management.

Another emerging area is the study of adipokines, hormones produced by adipose tissue such as leptin and ghrelin, as well as their associated micro-RNA levels.  These hormones influence appetite regulation and energy balance, and their levels tend to be elevated in individuals with obesity. While we do not yet have clear clinical guidelines linking specific adipokine levels to outcomes, research suggests that higher levels are associated with increased inflammation and metabolic dysfunction. Studies have also demonstrated that increased cytokines, or markers of inflammation, are associated with metabolic dysfunction in obesity.  In the future, measuring these markers may help stratify risk and guide personalized treatment strategies, as well as allow for personalized monitoring of response to treatment.

Although these approaches are not yet standard practice, they represent exciting directions in the evolving landscape of metabolic health monitoring.