Physical activity and diet improve after weight loss surgery, but fall short of federal guidelines

Reviewed by Emily Henderson, B.Sc.Jun 16 2022

In a long-term study of adults who have undergone bariatric weight loss surgery, University of Florida researchers found participants' physical activity and diet quality improved after surgery, but fell short of federal physical activity guidelines.

The findings, which appear in JAMA Network Open, suggest patients may need continued support to help them maintain weight loss and other health benefits of the surgery.

Bariatric surgery is an effective treatment for obesity and other associated conditions, such as diabetes, heart disease, sleep apnea and joint pain, but outcomes can vary from patient to patient.

Although evidence has established the association between bariatric surgery and improvement in cardiometabolic outcomes, postoperative lifestyle patterns -; which could help patients achieve long-term health benefits of bariatric surgery -; are not well understood."

Young-Rock Hong, Ph.D., M.P.H., study's lead author, assistant professor of health services research, management and policy in the UF College of Public Health and Health Professions and member of the UF Cancer Center

Patients who have had bariatric surgery might regain weight due to several factors, and a fraction of patients may have significant weight regain several years after surgery, said Crystal Johnson-Mann, M.D., M.P.H., a study author, an assistant professor and a minimally invasive/bariatric surgeon in the division of gastrointestinal surgery at the UF College of Medicine. Providing patients access to continued treatment by dietitians, clinical psychologists and bariatric physicians can help mitigate weight regain.

"Obesity is a chronic disease process and must be managed as one, like hypertension or diabetes," she said. "Patients have the best outcomes from bariatric surgery when it is fully utilized as an adjunct to lifestyle/behavioral changes, such as changes in physical activity and diet. Not all patients post surgery can be as physically active as desired due to ongoing neurologic, musculoskeletal or other factors, but physical activity should be highly encouraged in those who can engage in order to maximize the benefits of their metabolic surgery."

For the UF study, investigators analyzed 2015-2018 data from the National Health and Nutrition Examination Survey, a nationally representative study that collects data from a combination of interviews, physical examinations and laboratory tests. The UF researchers looked at self-reported data on physical activity and diet for more than 4,600 adult participants in three categories: people who had received bariatric surgery; people who met eligibility requirements for bariatric surgery but had not undergone the procedure; and people who had normal weight.

People who had undergone bariatric surgery reported spending more time per week doing moderate-to-vigorous physical activity than people who were eligible for surgery, but did not receive it. Yet, only 23% of patients who had bariatric surgery met federal physical activity guidelines, compared with 45% of people at normal weight. Current guidelines published by the U.S. Department of Health and Human Services recommend 150 minutes a week of moderate-intensity aerobic exercise or 75 minutes a week of vigorous aerobic activity.

An analysis of self-reported calorie intake and diet showed that patients who received bariatric surgery consumed the lowest number of calories a day of the three groups, but the quality of the food they ate, as measured by the Healthy Eating Index, was lower than participants in the normal weight group.

Beyond surgery-related factors that may affect weight regain, adults who have undergone bariatric surgery face the same environmental, social and cultural barriers as anyone attempting to maintain weight loss, said the study's senior author, Kathryn Ross, Ph.D., M.P.H., an associate professor of clinical and health psychology in the College of Public Health and Health Professions. These include maintaining a healthy diet in an environment where highly palatable, highly processed, high-calorie foods are cheap and plentiful, and the ability to engage in physical activity may be hampered by sedentary jobs, lack of access to safe spaces for walking and biking, and time restrictions due to work or caregiving responsibilities.

"The provision of nutritional counseling and support to help patients make and maintain postsurgical changes in their dietary intake and physical activity is key to supporting long-term weight loss maintenance," Ross said. "Offering positive, nonjudgmental support while helping patients set realistic, achievable goals can also benefit postoperative patients trying to make changes in their eating and activity patterns."