A Guideline-Directed Approach to Obesity Treatment

Abstract

This article summarizes and compares 18 sets of guidelines for adult obesity treatment, highlighting key recommendations for patient evaluation, lifestyle intervention, anti-obesity medications (AOMs), and metabolic and bariatric surgery. Guidelines are consistent in many regards, although there is divergence regarding preferred AOMs. Metabolic and bariatric surgery is still recognized as the most durable form of obesity treatment, and newer guidelines suggest these procedures at lower BMI thresholds for people with uncontrolled type 2 diabetes. Overall, guidelines for obesity treatment show a high degree of agreement, although updates are needed to incorporate new treatment innovations.

Despite the availability of effective treatments for weight management, the prevalence of obesity remains high. The current prevalence of obesity in adults is 41.9% in the United States (1) and 14.0% globally (2). Obesity is a chronic and progressive disease that increases the risk of developing several complications, including hypertension (3), type 2 diabetes (4), and osteoarthritis (5). Losses of ≥5% of initial weight produce multiple improvements in both physical and mental health (6).

Clinical practice guidelines help health care professionals (HCPs) make evidence-based decisions to optimize patient care. Systematic evaluation of the effectiveness of different weight management approaches has supported the development of several practice guidelines from various organizations, including guidelines from the U.S. National Institutes of Health published in 1998 (7), a joint initiative from the American Heart Association, the American College of Cardiology, and The Obesity Society released in 2013 (8), an Endocrine Society report published in 2015 (9), and a combined initiative from the American Association of Clinical Endocrinologists (AACE) and the American College of Endocrinology issued in 2016 (10). These guidelines have been reviewed and compared previously (11–13). Recently, several additional national and international guidelines for obesity management have been published that build upon prior recommendations and reflect new evidence about innovative interventions, including novel medications and devices, as well as the voluntary withdrawal from the market of a previously approved drug (lorcaserin) (14). Guidelines vary in methodology, scope, and critical questions addressed. In this article, we summarize and compare select guidelines for obesity management in adults, highlighting key recommendations for patient evaluation, lifestyle intervention, anti-obesity medications (AOMs), and metabolic and bariatric surgery.

General Overview of Guidelines

Of the 18 guidelines reviewed, two were published in 2013, three in 2015, one in 2016, one in 2017, four in 2020, two in 2022, four in 2023, and one in 2024 (Table 1). The guidelines were issued by organizations in the United States, Europe, Canada, the United Kingdom, Ireland, India, Australia, and Korea. Ireland’s guidelines were contextually adapted from the Canadian Adult Obesity Clinical Practice Guideline (15). Six guidelines address the full spectrum of obesity treatments (i.e., lifestyle, pharmacotherapy, devices, and metabolic and bariatric surgery); six include lifestyle, AOMs, and metabolic and bariatric surgery; three focus on pharmacotherapy; and three concentrate on metabolic and bariatric surgery (Table 1). Figure 1 summarizes some aspects and commonalities across most guidelines.

Table 1.

Select Obesity Treatment Guidelines

Guideline	Country	Topics Included				Preferred AOM (General or Based on Obesity-Related Complications/Diseases or Characteristics)
		Lifestyle	AOMs	Devices	Metabolic and Bariatric Surgery
AACE and American College of Endocrinology (10)	United States	X	X	X	X	Clinical characteristics or coexisting diseases, efficacy, side effects, warnings/contraindications, organ clearance, mechanisms of action, and available data for use under specific conditions are the basis for individualized weight loss pharmacotherapy; generalizable hierarchical algorithm applicable to all patients cannot be scientifically justified
American Gastroenterological Association (content contributions from Society of American Gastrointestinal and Endoscopic Surgeons, The Obesity Society, Academy of Nutrition and Dietetics, and North American Society for Pediatric Gastroenterology, Hepatology and Nutrition; endorsement with input by American Society for Gastrointestinal Endoscopy, American Society for Metabolic and Bariatric Surgery, American Association for the Study of Liver Diseases, and Obesity Medicine Association (31)	United States	X	X	X	X	In CVD, recommends against sympathomimetic agents such as phentermine and phentermine/topiramate ER and identifies lorcaserin and orlistat as safer alternatives; in type 2 diabetes, suggests antidiabetic agents that promote weight loss, such as GLP-1 receptor agonists, in addition to metformin
ADA (24)	United States	X	X	X	X	Recommends semaglutide and tirzepatide
National Health and Medical Research Council, Department of Health (32)	Australia	X	X	X	X	NR*
Department of Veterans Affairs and Department of Defense (prepared by the Management of Adult and Obesity Work Group, with support from the Veterans Affairs Office of Quality and Patient Safety and the U.S. Army Medical Command’s Office of Evidence-Based Practice) (37)	United States	X	X	X	X	Suggests liraglutide, naltrexone/bupropion, orlistat, or phentermine/topiramate; insufficient evidence to recommended for or against phentermine monotherapy, benzphetamine, diethylpropion, or phendimetrazine
Endocrine Society of India (20)	India	X	X	X	X	NR*
American Heart Association/American College of Cardiology/The Obesity Society (8)	United States	X	X		X	NR
Association for the Study of Obesity on the Island of Ireland, the Irish Coalition for People Living with Obesity, and the Health Service Executive Obesity National Clinical Programme (34)	Ireland	X	X		X	To maintain weight loss from health behavior changes, recommends liraglutide or orlistat; in type 2 diabetes, recommends semaglutide, liraglutide, naltrexone/bupropion, orlistat; in prediabetes, recommends liraglutide, orlistat
European Association for the Study of Obesity (33)	Europe	X	X		X	NR
KSSO (25)	Korea	X	X		X	NR
NICE (21)	United Kingdom	X	X		X	Recommends use of liraglutide, orlistat, or semaglutide based on different BMI cutoffs and risk factors
Obesity Canada and the Canadian Association of Bariatric Physicians and Surgeons (30)	Canada	X	X		X	NR
American Gastroenterological Association (46)	United States		X	X		Semaglutide 2.4 mg may be prioritized over other approved AOMs for most patients; recommends against the use of orlistat
Endocrine Society (co-sponsored by the European Society of Endocrinology and The Obesity Society) (9)	United States		X			Recommends against the use of sympathomimetic agents phentermine and diethylpropion in patients with uncontrolled hypertension or a history of heart disease and suggests lorcaserin and/or orlistat as alternatives; in type 2 diabetes, suggests the use of antidiabetic agents that promote weight loss, such as GLP-1 receptor agonists or SGLT2 inhibitors in addition to metformin
European Association for the Study of Obesity (55)	Europe		X			NR
American Association of Clinical Endocrinologists/American College of Endocrinology, The Obesity Society, American Society for Metabolic and Bariatric Surgery, Obesity Medicine Association, and American Society of Anesthesiologists (26)	United States			X	X	NA
European Association for Endoscopic Surgery (endorsed by the European chapter of the International Federation for the Surgery of Obesity and Metabolic Disorders, the European Association for the Study of Obesity, and the European Society for the Peri-Operative Care of the Obese Patient (50)	Europe				X	NA
ASMBS and IFSO (22)	United States/ International				X	NA

^*Orlistat was only approved medication. NA, not applicable; NR, not reported; SGLT2, sodium–glucose cotransporter 2.

Figure 1.

Commonalities across obesity treatment guidelines. CKD, chronic kidney disease; CVD, cardiovascular disease; MASH, metabolic dysfunction–associated steatohepatitis.

Obesity Diagnosis and Patient Evaluation

All of the guidelines use BMI, calculated as weight in kilograms divided by height in meters squared, as a screening measure for obesity. BMI is strongly correlated with body fat percentage (16). However, it has several limitations, such as not providing direct assessment of adiposity and reduced accuracy in some populations, including older adults and athletes (17). Because of these limitations, guidelines emphasize that additional assessments should be used in conjunction with BMI when considering obesity-related health risks and treatment approaches.

Guidelines define overweight as a BMI of 25.0–29.9 kg/m² and obesity as a BMI ≥30 kg/m². Some guidelines also include ethnicity-specific cut points, which are suggested based on demonstrated differences in body composition and cardiometabolic risk at lower BMI levels in some populations (16,18–20). Guidelines developed by the National Institute for Health and Care Excellence (NICE) (21) and by the American Society of Metabolic and Bariatric Surgery (ASMBS) and the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) (22) use an obesity cut point of ≥27.5 kg/m² for people who are Asian, as recommended by the World Health Organization expert consultation panel (23). The American Diabetes Association (ADA) (24), Korean Society for the Study of Obesity (KSSO) (25), Endocrine Society of India (20), and joint guidelines on perioperative nutrition, metabolic, and nonsurgical support of patients undergoing bariatric procedures (26) use a cut point for obesity of ≥25 kg/m², as cited in the Consensus Statement for Asian Indians of the Metabolic and Obesity Summit (27) and guidelines of the Japan Society for the Study of Obesity (28) and the KSSO (29).

Several guidelines also include measures of waist circumference (8,10,20,24,25,30–34), waist-to-hip ratio (24,31), and/or waist-to-height ratio (21,24) to provide added information about central adiposity. These additional measures are typically recommended for individuals with a BMI <35 kg/m² based on the premise that individuals with a BMI ≥35 kg/m² likely have reached elevated waist circumference thresholds, and these measures provide limited additional risk information (7). Specific cut points to define abdominal obesity vary based on sex and ethnicity, with most guidelines typically referencing the International Diabetes Federation (among people who are White: men ≥94 cm and women ≥80 cm) (35) or the Adult Treatment Panel III thresholds (among people who are White: men ≥102 cm and women ≥88 cm) (36), with smaller waist circumference criteria for specific ethnicities.

Beyond anthropometric measures, the presence of obesity complications and related diseases is commonly considered in determining risk and treatment decisions. Formalized staging systems are used by three guidelines. The Canada, Ireland, and India guidelines include the Edmonton Obesity Staging System (EOSS) (20,30,34), and the AACE guidelines include the AACE Obesity Staging System (10). The EOSS considers medical, mental, and functional aspects of obesity and classifies individuals into five graded categories based on their morbidity and health-risk profile. The stages range from 0 (no apparent obesity-related risk factors or comorbidities) to 4 (presence of severe disability or end-stage organ failure due to obesity). The AACE Obesity Staging System is based on ethnicity-specific BMI cut points, along with the assessment of adiposity-related complications. Stage 0 is assigned to people with overweight or obesity who have no obesity-related complications, whereas stages 1 and 2 include individuals with overweight or obesity with one mild-to-moderate complication (stage 1) or at least one severe complication (stage 2).

Multiple guidelines recommend a comprehensive initial assessment to determine treatment selection and tailoring (8,10,20,21,24,30–34,37). This assessment includes a thorough physical examination and medical history, with attention given to existing health conditions that may contribute to weight gain or complicate treatment, weight distribution, weight gain pattern and trajectory, and previous weight loss attempts. Guidelines also recommend that clinicians assess factors that may influence a patient’s ability to adopt and sustain health-related behaviors, including eating habits, physical activity, sleep, stress, behavioral and psychological challenges, motivation, readiness to change, and cultural, social, socioeconomic, and environmental variables. Laboratory assessments and other evaluations should be conducted to identify contributors to obesity and possible complications, such as blood pressure, lipids, thyroid function, and glycemic parameters. Guidelines also recommend reviewing patients’ medications to identify any that may contribute to weight gain and potentially switching these to weight-neutral or weight-reducing medications after communicating with the patient’s primary care provider (9).

As highlighted in the NICE guidelines (21), obesity-related complications should be managed independently of obesity treatment. Effective treatments for hypertension, dyslipidemia, type 2 diabetes, and other diseases should not be withheld in expectation of weight loss. Improvements in obesity-related diseases and complications should be assessed during treatment, and medications can potentially be decreased or discontinued after successful weight reduction and maintenance.

Treatment Initiation and Evaluation

The selection and initiation of obesity treatment is a collaborative decision between an individual and an HCP based on the assessment of the multiple factors outlined above. Treatment goals for adults are individualized with consideration of the patient’s desired goal weight and the percentage reduction in baseline weight likely to result in improvements in obesity-related risk factors and complications, physical function, and psychosocial well-being. Goals should be monitored regularly to assess progress and make necessary adjustments to treatment. Most guidelines emphasize the benefits of achieving a ≥5% reduction in body weight at 6 months and maintaining it long term (8,20,24,25,31,32,37), with greater improvements observed at higher weight losses.

Lifestyle Modification

Twelve guidelines that we reviewed include recommendations for lifestyle intervention, which is considered the cornerstone and first-line treatment of obesity (Table 2). Comprehensive interventions produce average weight losses of 5–8 kg at 1 year, equal to reductions of 5–8% of baseline weight (8). The guidelines generally identify similar components of lifestyle modification approaches, which include goal-setting, self-monitoring, problem-solving, stimulus control, cognitive therapy, and relapse prevention. These components have been successfully used in obesity treatment trials such as the Diabetes Prevention Program (38) and the Look AHEAD (Action for Health in Diabetes) trial (39).

Table 2.

Summary of Recommendations for Lifestyle Interventions From Obesity Treatment Guidelines

Guideline	Reduced-Calorie Diet?	Calorie Target, kcal/day	Suggested Diet	Increased Physical Activity?	Physical Activity Target/Type	Behavioral Modification Program	Counseling Frequency
American Gastroenterological Association (31)	Yes	1,200–1,500 for women, 1,500–1,800 for men, or estimation of individual daily energy requirements and 500–750 deficit	Limit consumption of liquid calories; individualized, structured meal plan; focus on balanced diet rather than specific macronutrient composition or elimination diets; emphasize designing plan to maximize adherence	Yes	≥10,000 steps/day; ≥150 minutes/week of cardiovascular exercise; 200–300 minutes/week for maintenance or to minimize regain	Comprehensive lifestyle intervention that provides structured behavior strategies to facilitate adherence to diet and activity recommendations	14 visits for 6 months (weekly for the first month, then biweekly for months 2–6) and monthly thereafter for 1 year
ADA (24)	Yes	500–750 deficit	Energy deficit regardless of macronutrient composition, tailored to individual preferences and nutritional needs	Yes	200–300 minutes/week for weight loss maintenance	Intensive behavioral intervention	16 or more sessions in 6 months; long-term weight maintenance programs with monthly contact
Association for the Study of Obesity on the Island of Ireland, the Irish Coalition for People Living with Obesity, and the Health Service Executive Obesity National Clinical Programme (34)	No	NA	Any of the following (each with different goal targets and not all for weight loss): calorie-restricted dietary pattern emphasizing variable macronutrient distribution ranges; Mediterranean; vegetarian; Portfolio diet; low-glycemic index; DASH; Nordic; partial meal replacements; intermittent or continuous calorie restriction; pulses; vegetables and fruit, nuts, whole grains, dairy foods	Yes	30–60 minutes of moderate- to vigorous-intensity aerobic exercise most days of the week for cardiorespiratory fitness, muscle mass maintenance, weight loss, and reductions in abdominal visceral fat and ectopic fat; increasing exercise intensity can achieve greater increases in cardiorespiratory fitness; resistance training may promote weight maintenance or modest increases in muscle mass or fat-free mass and mobility; regular (≥120 minutes/week) aerobic exercise may improve overall mental health and health-related quality of life in adults who are middle-aged or older	Multicomponent psychological interventions combining behavior modification (goal-setting, self-monitoring, problem-solving), cognitive therapy (reframing), and values-based strategies	Longitudinal care
AACE and American College of Cardiology (10)	Yes	500–750 deficit	Reduced-calorie healthy meal plan individualized based on personal and cultural preferences; meal plans can include Mediterranean, DASH, low-carbohydrate, low-fat, volumetric, high protein, and vegetarian; meal replacements; very-low-calorie diet is an option in selected patients and under medical supervision	Yes	Voluntary aerobic exercise progressing to >150 minutes/week performed on 3–5 days; resistance exercise: single-set repetitions involving major muscle groups 2–3 times/week; reduced sedentary behavior; individualized program based on preferences that considers physical limitations	Interventional package that includes any number of the following: self-monitoring (food intake, exercise, weight), goal-setting, education, problem-solving, stimulus control, behavioral contracting, stress reduction, psychological evaluation, counseling and treatment when needed, cognitive restructuring, motivational interviewing, and/or mobilization of social support structures	NR
AHA/ACC/TOS (8)	Yes	1,200–1,500 for women, 1,500–1,800 for men, 500 or 750 deficit	Calorie-restricted diet based on individual preferences and health status	Yes	Aerobic exercise ≥150 minutes/week; 200–300 minutes/week to maintain weight and minimize weight regain	Comprehensive program that assists with adhering to lower-calorie diet and increasing physical activity through the use of behavioral strategies	≥14 sessions in 6 months; monthly or more frequently for weight loss maintenance
KSSO (25)	Yes	500–1,000 deficit; degree of energy restriction should be individualized based on characteristics and medical conditions	Various dietary methods can be selected, but energy intake should be reduced and nutritionally appropriate methods are recommended; individualize macronutrient composition based on individual characteristics and medical conditions	Yes	Aerobic exercise ≥150 minutes/week performed on 3–5 days; additional resistance training 2–3 times/week using large muscle groups; 250–300 minutes/week for more meaningful weight loss	Self-monitoring, reinforcement, stimulus control, alterative behavior, and cognitive reconstruction	>6 months and ≥1 year for weight loss maintenance
Endocrine Society of India (20)	Yes	NR	Hypocaloric diet with reduced portion sizes, balanced macronutrients and micronutrients (e.g., plate model), mindfulness, dietary monitoring, and compatibility with weight-related comorbidities	Yes	Aerobic exercise (30–60 minutes of moderate to vigorous intensity on most days of the week) up to 300 minutes/week for moderate intensity or 150 minutes/week for vigorous intensity; high-intensity interval training; resistance exercise; physical activity can be accumulated throughout the day in blocks as short as 10 minutes; work-related activity should be encouraged whenever possible	Medical nutrition therapy and physical activity counseling	NR
National Health and Medical Research Council, Department of Health (32)	Yes	Dietary interventions designed to produce ∼600 deficit*	Tailor to individual dietary preferences and to include a wide variety of nutritious foods	Yes	Aerobic exercise 300 minutes/week of moderate-intensity activity or 150 minutes/week of vigorous activity or an equivalent combination of moderate-intensity and vigorous activities	Multicomponent individually tailored lifestyle intervention that includes a healthy eating plan, increased physical activity, and support for behavioral change	NR
NICE (21)	Yes	600 deficit or reduce calories by lowering fat content; consider low-calorie diets (800–1,600), but these are less likely to be nutritionally complete	Tailor to individual dietary preferences and allow for flexible and individual approach to reducing calorie intake; do not use unduly restrictive and nutritionally unbalanced diet because they are ineffective in the long term and can be harmful	Yes	Meet recommendations in U.K. Chief Medical Officers’ physical activity guidelines; 60–90 minutes/day of activity to avoid regaining weight for those with obesity; lifestyle and supervised exercise programs to reduce time spent inactive	Multicomponent intervention that includes behavior-change strategies to increase physical activity or decrease inactivity, improve eating behavior and diet quality, and reduce energy intake	Offer regular, nondiscriminatory long-term follow-up by a trained professional; ensure continuity of care within the multidisciplinary team through good record-keeping
Department of Veterans Affairs and Department of Defense (37)	Yes	500–1,000 deficit	Dietary approaches that contribute to a negative energy balance to achieve weight loss; meal replacements can be used as a component of a comprehensive lifestyle intervention; a low-carbohydrate diet may be preferable over a low-fat diet for patients who prioritize short-term (up to 6 months) weight loss	Yes	Aerobic, resistance, and/or lifestyle physical activity; while not reviewed in this guideline, higher volumes of physical activity (e.g., ≥300 minutes/week of moderate activity) were associated with improved weight maintenance after weight loss	Interventions that combine behavioral, dietary, and physical activity components that aim to produce a negative energy balance, usually including goal-setting, self-monitoring, stimulus control, cognitive strategies, identification of barriers to change, problem-solving, relapse prevention, and support	NR
Obesity Canada and the Canadian Association of Bariatric Physicians and Surgeons (30)	No	NA	Personalized to meet individual values and preferences and a treatment goal to support a dietary approach that is safe, effective, nutritionally adequate, culturally acceptable, and affordable for long-term adherence; nondieting approach; multiple medical nutrition therapies to improve health-related outcomes to support long-term adherence (e.g., calorie-restricted, Mediterranean, and Portfolio dietary patterns)	Yes	30–60 minutes of moderate-to vigorous-intensity aerobic exercise on most days of the week; resistance training (duration not specified); increasing exercise intensity to achieve greater increases in cardiorespiratory fitness	Multicomponent psychological interventions combining behavior modification (goal-setting, self-monitoring, and problem-solving), cognitive therapy (reframing), and values-based strategies	Longitudinal care
European Association for the Study of Obesity (33)	Yes	600 deficit	Individualized energy restriction taking into account eating habits, physical activity, comorbidities, and previous dieting attempts; prescribing an energy-restricted diet may require a nutritionist/dietitian; balanced hypocaloric diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize; low-glycemic-load diets may be slightly superior to hypocaloric diets in the short term	Yes	>150 minutes/week of moderate aerobic exercise such as brisk walking should be combined with three weekly sessions of resistance exercise to increase muscle strength; further objectives should be to reduce sedentary behavior and increase daily activities (e.g., walking or cycling instead of using a car and climbing stairs instead of using elevators)	Cognitive behavioral therapy that includes components such as self-monitoring, techniques controlling the process of eating, stimulus control, and reenforcement, as well as cognitive and relaxation techniques	NR

^*Reported as 2,500 kJ/day. DASH, Dietary Approaches to Stop Hypertension; NA, not applicable; NR, not reported.

Most guidelines recommend regularly scheduled counseling visits, with some recommending at least 14–16 sessions in the first 6 months and monthly visits for ≥1 year for weight loss maintenance (8,24,25,31). Several guidelines recommend that counseling be delivered in individual or group sessions led by a trained interventionist. Some guidelines highlight the potential of technology-based interventions such as texting or Internet-based approaches. For example, the Canadian guidelines recommend management strategies through Web-based platforms or mobile devices, as well as the use of wearable activity-tracking technology as part of a comprehensive strategy for weight loss (30).

Ten of the 12 guidelines advise that patients should be prescribed a reduced-calorie diet, whereas expert panels from Canada and Ireland include nondieting approaches in addition to calorie-restricted dietary patterns (30,34). Increased caloric restriction is associated with increased weight loss at 6 months, but differences in weight reduction between severely and moderately restricted diets decline over 12–18 months of nonintervention follow-up (40). Thus, most guidelines recommend a moderately restricted or low-calorie target, with suggested daily energy deficits of 600 (21,32,33), 500–750 (8,24,31), or 500–1,000 (10,25,37) kcal/day. Alternatively, some guidelines recommend a daily target of 800–1,600 (21) or 1,200–1,500 kcal/day for women and 1,500–1,800 kcal/day for men (8,31).

There are few long-term differences in weight loss between diets with markedly different macronutrient composition, such as low-carbohydrate versus low-fat regimens (8,41). Thus, the majority of guidelines recommend a hypocaloric diet that provides ample fruits and vegetables, lean protein, and other foods that promote cardiometabolic health, tailored to personal and cultural preferences to optimize long-term adherence (Table 2). Examples of such diets include energy-restricted versions of the Mediterranean diet, the Dietary Approaches to Stop Hypertension diet, and low-fat and low-glycemic-index dietary patterns. Structured meal plans, portion-controlled servings, and meal replacements (e.g., shakes and bars) are also suggested as additional dietary options that may promote an individual’s ability to adhere to a reduced-calorie diet (8,10,34,42).

All guidelines recommend increased physical activity, tailored to patients’ capabilities and preferences. Most suggest starting with at least 30 minutes of moderate-intensity exercise on 5 or more days a week (>150 minutes/week) during weight loss and progressing to 200–300 minutes/week to promote weight loss maintenance (Table 2). Engaging in resistance training two to three times per week is recommended by some guidelines, such as those from Canada (30), given evidence that different types of physical activity generate distinct benefits. The benefits of regular aerobic activity of moderate to vigorous intensity include facilitating cardiorespiratory fitness, muscle mass maintenance, weight loss, mental health, health-related quality of life, and reductions in abdominal visceral fat and ectopic fat (34). Resistance training can increase physical mobility and strength as well as enhance (or at least preserve) muscle mass.

AOMs

Fifteen guidelines include recommendations for AOMs, all of which recommend AOMs as an adjunct to a reduced-calorie diet and increased physical activity, congruent with the package inserts of AOMs and specified by the U.S. Food and Drug Administration (FDA) and other regulatory bodies (Table 1). In considering eligibility for AOMs, the majority of guidelines recommend a BMI threshold of ≥30 kg/m² or ≥27 kg/m² with at least one obesity-related comorbidity, consistent with marketing authorizations; some also included ethnicity-specific criteria (20,24,25). Additional criteria include unsuccessful attempts to lose weight using dietary, exercise, and behavioral approaches or patients not achieving their target weight loss goals (21). The guidelines encourage HCPs to speak with patients about the potential benefits and limitations of pharmacotherapy, including potential adverse effects and contraindications to treatment, the medication’s mechanism of action, the schedule of medical monitoring required, and the course of treatment, including the possibility of indefinite (i.e., chronic) use to maintain improvements in body weight and health.

Particular AOMs that are described in guidelines differ based on the medications available in the country at the time of publication. Current medications that have been approved by the FDA for chronic weight management include orlistat in 1999, phentermine-topiramate in 2012, liraglutide in 2014, naltrexone-bupropion in 2014, semaglutide in 2021, and tirzepatide in 2023. Setmelanotide was FDA-approved in 2020 for individuals with obesity resulting from genetic disorders. From meta-analyses, on average, participants tend to have the smallest weight losses with orlistat and largest weight losses with tirzepatide (43). At 1 year, individuals on placebo lost 6.1 kg, which was less than the 10.3 kg lost by those on orlistat (44). At 72 weeks, participants on placebo lost 2.4 kg, which was significantly less than those on all tirzepatide doses, who experienced losses of 16.1 kg with the 5-mg dose, 22.2 kg with 10 mg, and 23.6 kg with 15 mg (45).

Most guidelines do not specify the precise order in which AOMs should be prescribed and instead make general recommendations with no preferred treatment options. However, some guidelines include suggestions about selecting specific AOMs, either generally or based on specific patient characteristics (Table 1). For example, the NICE guidelines have varied recommendations based on the specific medication and patient’s BMI (21). Orlistat is recommended at a BMI ≥30 kg/m² or ≥28 kg/m² for those with associated risk factors. In contrast, semaglutide is recommended for individuals with a BMI ≥35 kg/m² or 30–34.9 kg/m² in those who meet the criteria for referral to specialist weight management services. Use of semaglutide is also recommended at lower BMI thresholds, usually reduced by 2.5 kg/m², for people from South Asian, Chinese, other Asian, Middle Eastern, Black African, or African Caribbean family backgrounds who also have at least one weight-related comorbidity and are using the medication within a specialist weight management service. Liraglutide is recommended for individuals with a BMI ≥35 kg/m² or ≥32.5 kg/m² for members of minority ethnic groups known to be at equivalent risk of the consequences of obesity at lower BMI levels than the White population who meet other specified criteria.

Other guidelines include specific prescribing recommendations based on obesity-related complications. For example, the Canadian obesity guidelines recommend consideration of liraglutide 1.8 mg daily or semaglutide in conjunction with health behavior changes in treating people with metabolic dysfunction–associated steatohepatitis (MASH) and overweight or obesity for weight loss and improvement of MASH parameters (30). They recommend that liraglutide 3.0 mg daily be considered in conjunction with health behavior changes in treating people with obstructive sleep apnea and a BMI ≥30 kg/m². The American Gastroenterological Association recommends semaglutide as the prioritized medication over other approved AOMs given the magnitude of net benefit (46). For individuals with diabetes and overweight or obesity, the ADA recommends as the preferred pharmacotherapy a glucagon-like peptide 1 (GLP-1) receptor agonist or a dual GLP-1/glucose-dependent insulinotropic polypeptide (GIP) receptor agonist with substantial weight loss efficacy (i.e., semaglutide or tirzepatide).

Guidelines recommend that patients be monitored monthly for the first 3 months and then at least every 3 months to assess for efficacy and adverse effects. Typically, a specific weight loss agent should only be continued when patients lose ≥5% of their initial body weight in the first 3 months and there are no concerns pertaining to safety and tolerability. Treatment should be discontinued in nonresponders or if there are safety or tolerability issues at any time. If possible, an alternative therapy should be used in these cases. The NICE guidelines include that semaglutide should be used for a maximum of 2 years; however, most other guidelines recognize the chronicity of obesity and advise that long-term treatment is necessary.

Devices

Eight guidelines include novel devices that have been approved for obesity management by the FDA and other regulatory bodies. FDA-approved intragastric balloons include the ReShape Duo, Orbera, and Obalon Ballons. These devices promote satiety by taking up space in the stomach and delaying gastric emptying. They are approved for patients with a BMI of 30–40 kg/m². Intragastric balloons are available for 6-month implantation to treat obesity, after which they are deflated and extracted endoscopically. Thus, their long-term utility and safety are unclear. In clinical trials, intragastric balloons combined with lifestyle intervention produced an average weight loss of 10.2% at 6 months, compared with 3.3% with lifestyle alone (47).

Endoscopic sleeve gastroplasty, another device, decreases gastric volume by creating a sleeve-like tubularized conduit using sutures endoluminally placed through the gastric wall. At 52 weeks, endoscopic sleeve gastroplasty plus lifestyle modification resulted in a weight loss of 13.6% compared with 0.8% for lifestyle alone (48). Limited published data are available about this approach.

In 2019, the Gelesis100 device was approved by the FDA for obesity treatment in people with a BMI of 25–40 kg/m². It is an orally administered hydrogel capsule that releases cellulose and citric acid particles to increase bulk in the stomach. At 6 months, the Gelesis100 produced a mean weight loss of 6.4% compared with a loss of 4.4% with placebo (49).

Other devices that are mentioned in guidelines but are no longer marketed in the United States include gastric emptying systems and electrical stimulation systems. Obesity treatment devices have not been approved in many countries, and currently they are largely not covered by insurance. Thus, most guidelines conclude that there are insufficient data to provide guidance regarding these novel approaches.

Metabolic and Bariatric Surgery

Fifteen guidelines include metabolic and bariatric surgery (Table 1). All guidelines recommend a comprehensive preoperative workup, including a medical, nutritional, and psychological evaluation. Special considerations before surgery are given to manage modifiable risk factors, such as addressing nutrient deficiencies, smoking cessation, and obstructive sleep apnea and evaluating cardiopulmonary function, all with the goal of reducing the risk of perioperative complications and improving outcomes. Additional considerations, as indicated, include esophagogastroscopy (50), gastrointestinal and endocrine evaluation (26), optimization of glycemic control (26), pregnancy counseling (21,26), verification of cancer screening (26), and evaluation of biliary symptoms using ultrasonography (37).

Guidelines are generally consistent about using BMI and obesity-related comorbidities to identify candidates for bariatric surgery. Eleven guidelines (8,10,21,26,30–34,37,50) recommend metabolic and bariatric surgery for individuals with a BMI ≥40 kg/m² regardless of the presence, absence, or severity of obesity-related conditions. The ASMBS and the IFSO recommend a lower BMI range, indicating that metabolic and bariatric surgery may be considered for individuals with a BMI ≥35 kg/m² regardless of obesity-related conditions (22). Twelve guidelines suggest that surgery be considered for people with a BMI of 35–39.9 kg/m² and the presence of metabolic disease (8,10,21,24,26,31–34,37,50). But, even without metabolic disease, three guidelines recommend that surgery be considered starting at a BMI of 30 kg/m² for adults who do not achieve substantial or durable weight loss or obesity disease–related improvement using nonsurgical methods (22,30,34). Ten guidelines recommend that surgery be considered for individuals with a BMI ≥30 kg/m² with poorly controlled type 2 diabetes despite medical therapy (10,21,22,24,26,30,34,37,50). Guidelines from Europe (50) and from AACE (10) include individuals with a BMI ≥30 kg/m² and poorly controlled arterial hypertension and metabolic syndrome despite medical therapy.

Some guidelines contain BMI cut point guidance based on ethnicity (22,24–26). For example, the KSSO guidelines have lower BMI cut points for bariatric surgery. They recommend consideration of surgery for all individuals who have not lost weight despite behavioral intervention and medical management and who have a BMI ≥30 kg/m² with obesity-related comorbidities or ≥27.5 kg/m² with type 2 diabetes or poorly controlled blood glucose (25). The NICE guidelines recommend that a lower BMI threshold (reduced by 2.5 kg/m²) be used for individuals in South Asian, Chinese, other Asian, Middle Eastern, Black African, or African Caribbean populations (21). Guidelines from India use BMI thresholds for bariatric surgery of >32.5 kg/m² with comorbidity and >37.5 kg/m² without comorbidity (20).

Guidelines recommend that the choice of surgery should be patient-centered, taking into account individual factors and preferences, as well as the expertise of the surgeon and surgical team. However, laparoscopic techniques are usually preferred because they are associated with reduced complications and faster recovery. Currently, the Roux-en-Y gastric bypass and sleeve gastrectomy are the dominant procedures, together accounting for about 90% of worldwide operations (22). The anticipated loss of excess weight at 2 years is 70% with the Roux-en-Y gastric bypass and 60% with sleeve gastrectomy (51,52), which is equal to reductions in baseline weight of ∼25 and 20%, respectively. Adjustable gastric banding is no longer widely used because of suboptimal long-term outcomes.

All 15 guidelines provide postoperative guidance that recommends long-term multicomponent follow-up and monitoring, including behavioral and nutritional guidance. Nine guidelines recommend micronutrient and/or macronutrient supplementation to prevent deficiencies (21,24,26,30–32,34,37,50), and three advise delaying pregnancy during the weight loss phase after surgery (30,37,50). Most of the guidelines recognize obesity as a chronic and relapsing condition. Although metabolic and bariatric surgery is generally considered the most effective treatment of severe obesity, weight regain may occur (53). Multimodal strategies that integrate more intensive lifestyle modification and pharmacotherapy should be considered under these circumstances.

Discussion

Obesity treatment guidelines provide evidence-based recommendations and/or expert opinion for HCPs so they can provide the best treatment to patients. Despite being produced by different organizations from around the globe, the guidelines discussed in this review share many commonalities. There is agreement on the use of BMI as a screening tool for obesity and the addition of other anthropometrics, as well as examination for obesity complications and related diseases, to guide treatment selection. In addition, lifestyle intervention is universally recommended as the first-line treatment of obesity. Most guidelines are also concordant in terms of thresholds at which to consider metabolic and bariatric surgery. However, given the new second-generation AOMs that have resulted in significantly improved weight losses and amelioration of obesity-related conditions (i.e., semaglutide and tirzepatide), updating and disseminating guidelines that incorporate these strategies is urgently needed.

Despite many elements of agreement, some differences have started to emerge among guidelines, particularly concerning the selection of AOMs. For example, the 2022 Canadian guidelines use the general marketing authorization for all AOMs (i.e., BMI ≥30 kg/m² or ≥27 kg/m² with an obesity-related complication), including for semaglutide. By contrast, the 2023 NICE guidelines recommend semaglutide at a BMI ≥35 kg/m² or 30–34.9 kg/m² with an obesity-related complication while meeting the criteria for referral to specialist weight management services, with lower BMI thresholds for certain ethnicities. The NICE guidelines also limit use of semaglutide to 2 years because of the restricted time for specialist weight management services and lack of evidence for longer-term use. In addition, in models in which time on treatment was increased to 3 years, the medication was no longer cost-effective (54). These variations are likely a result of different perspectives, including the way recommendations were formulated, considerations of cost, and how health care is provided and financed in each country.

A common recommendation in several guidelines (10,20,25,26,30,31,33,34,55) is a complications-centric approach to care, in which the goal of treatment is to improve health by preventing and treating obesity complications and improving quality of life, rather than just the loss of weight per se.

Semaglutide and tirzepatide are often not covered by insurance or carry strict restrictions for their use, and their cost is >$1,000 USD per month in the United States, placing this treatment out of reach for many individuals. In addition, demand for these medications has outpaced supply. Research is needed to examine the economics and cost-effectiveness of AOMs and how they compare with other treatment approaches. Advocacy efforts are needed to expand access to and affordability of these treatments.

Updates to most guidelines will be needed because of recent groundbreaking data, including results from the Semaglutide Effects on Cardiovascular Outcomes in People with Overweight or Obesity (SELECT) trial and data from the SURMOUNT research program supporting the approval of a new AOM, tirzepatide, as discussed elsewhere in this article collection (p. 303) (56). The SELECT trial randomized adults ≥45 years of age with preexisting cardiovascular disease and a BMI ≥27 kg/m² but no history of type 2 diabetes to once-weekly subcutaneous semaglutide 2.4 mg or placebo (57). Semaglutide, relative to placebo, was associated with a 20% reduced risk of a composite of death from cardiovascular causes, nonfatal myocardial infarction, and nonfatal stroke at a mean duration of 33 months. These landmark results further support the use of semaglutide and have important implications for supporting wider use of second-generation AOMs. Tirzepatide, a dual GLP-1/GIP receptor agonist in a single molecule, was approved by the FDA for chronic weight management in 2023. In the 72-week SURMOUNT-1 trial, participants with overweight/obesity but without diabetes lost an average of 15.0% of their initial weight with tirzepatide 5 mg, 19.5% with 10 mg, and 20.9% with 15 mg relative to 3.1% with placebo (45). Several other novel AOMs are in the pipeline, and research and guidance about the selection of appropriate AOMs is urgently needed. Because of a lack of evidence, there are other important gaps in guidelines related to switching medications and weight loss maintenance plans, as well as the role of lifestyle modification with second-generation AOMs (58).

Guidelines offer an important mechanism for improving the quality of care provided to patients while containing health care costs and decreasing variability in clinical practice. However, they do not fully address the overall low utilization of treatments for obesity. For example, in the United States, <1% of eligible adults undergo bariatric surgery each year, and <2% of individuals who are eligible for pharmacotherapy receive treatment (59–62). Low utilization of these treatments is related to multiple factors, including a lack of insurance or underinsurance, limited access to treatments, public concern about the safety and/or long-term efficacy of some interventions, and lack of knowledge about treatments among HCPs (63). Efforts are needed to ensure the clinical applicability of guidelines and the involvement of multi-sectorial stakeholders in their development and to develop strategies to maximize the uptake and implementation of available treatments based on these guidelines.

Traditionally, obesity treatment has been thought of as a triad of lifestyle intervention, pharmacotherapy, and metabolic and bariatric surgery. Novel devices are approved for short-term (≤6 months) weight management among individuals with a BMI of 30–40 kg/m² who have been unable to achieve weight loss with a supervised weight control program. Because of a lack of research and insurance coverage, guidelines do not include information about these approaches and how they fit into the continuum of obesity care. Further research is needed to assess the efficacy of these approaches and their potential place in the toolbox of obesity treatments.

With the emergence of new innovations for weight management, including highly effective AOMs, it is crucial that thoughtful guidance be developed to provide recommendations to clinicians about using these treatment options. Given the enormous progress in obesity treatment, clinical practice guidelines will need to be updated. Efforts are needed to promote the adoption and use of guidelines in clinical practice to improve patient outcomes.