What are the current treatment options for weight reduction?

Current Treatment for Weight Reduction

Comprehensive lifestyle modification combining diet, physical activity, and behavioral therapy is the foundation of all weight reduction efforts, with GLP-1 receptor agonist-based pharmacotherapy added for patients with BMI ≥30 kg/m² or BMI ≥27 kg/m² with comorbidities who fail to achieve adequate weight loss with lifestyle changes alone. 1

Initial Assessment and Goals

• Target a 5-10% weight loss from baseline, which provides substantial health benefits including reduced cardiovascular events and prevention of type 2 diabetes 1
• Evaluate within 3 months to determine if lifestyle changes are effective; if minimal weight loss occurs, escalate to pharmacotherapy or surgical referral 1
• Screen for obesity-related complications including type 2 diabetes (HbA1c ≥6.5%), hypertension (BP ≥130/80 mmHg), dyslipidemia, sleep apnea, and nonalcoholic fatty liver disease 1

Dietary Intervention

• Reduce calorie intake by 500-1000 kcal/day to achieve 1-2 pound weight loss per week 1
• For BMI 25-29.9 kg/m² with cardiovascular risk factors or BMI 30-34.9 kg/m²: reduce by 500 kcal/day 1
• For BMI ≥35 kg/m²: reduce by 500-1000 kcal/day 1
• Ensure adequate protein, vitamins, and minerals while restricting calories 1
• Portion-controlled servings, prepackaged meals, and liquid meal replacements enhance adherence and weight loss compared to self-selected foods 1, 2
• Low-fat diets combined with reduced carbohydrates facilitate caloric reduction 1

Physical Activity Requirements

• Minimum 150 minutes per week of moderate-intensity aerobic exercise (30-60 minutes per day, at least 5 days per week) 1
• For weight loss maintenance: 200-300 minutes per week of moderate-intensity or ≥150 minutes per week of vigorous activity 1
• Add resistance exercises 2-3 times per week to enhance muscular strength 1
• Gradually increase activity over time based on current fitness level and complications 1

Behavioral Modification

• Implement at all stages of treatment, including those on pharmacotherapy or post-bariatric surgery 1
• Use self-monitoring of food intake, body weight, physical activity, and cravings 1
• Apply stress management, stimulus control, problem-solving, and cognitive restructuring techniques 1
• High-intensity behavioral interventions require 14 visits over 6 months (weekly for month 1, biweekly for months 2-6), then monthly for 1 year 1
• Web-based, phone-based, or tablet-based tools may support lifestyle changes 1

Pharmacotherapy Indications and Options

Initiate pharmacotherapy when:

• BMI ≥30 kg/m² regardless of comorbidities 1, 3
• BMI ≥27 kg/m² with at least one obesity-related complication 1, 3
• Patients require more urgent weight loss due to severe obesity 1
• Inadequately controlled obesity-related complications require greater weight loss 1
• Lifestyle intervention alone fails to achieve adequate weight loss 1

First-line pharmacotherapy:

• GLP-1 receptor agonist-based medications achieve 15-25% weight reduction and reduce cardiovascular events in patients with established CVD 1
• Phentermine as short-term adjunct (a few weeks) for BMI ≥30 kg/m² or BMI ≥27 kg/m² with risk factors 1, 3

Phentermine-specific considerations:

• Dose: 15-30 mg approximately 2 hours after breakfast 3
• Maximum 15 mg daily for severe renal impairment (eGFR 15-29 mL/min/1.73 m²) 3
• Avoid in eGFR <15 mL/min/1.73 m² or end-stage renal disease 3
• Contraindicated in cardiovascular disease, uncontrolled hypertension, hyperthyroidism, glaucoma, pregnancy, and history of drug abuse 3
• Risk of primary pulmonary hypertension and valvular heart disease, though rare 3
• Discontinue if tolerance develops rather than increasing dose 3

Bariatric Surgery

• Consider for BMI ≥40 kg/m² or BMI ≥35 kg/m² with comorbidities when less invasive methods have failed 1
• Achieves approximately 25-30% weight loss 1
• Follow-up minimum every 3 months during first year, then every 6 months while weight loss is maintained 1

Common Pitfalls to Avoid

• Do not use phentermine in combination with other weight loss drugs including over-the-counter preparations, herbal products, or SSRIs—safety and efficacy not established 3
• Avoid late evening medication with phentermine due to insomnia risk 3
• Do not exceed recommended phentermine dose when tolerance develops; discontinue instead 3
• Screen for depression, anxiety, and binge eating disorder before initiating treatment as these derail weight loss efforts 1
• Review medications that may cause weight changes (antidepressants, antihyperglycemics) 4
• Ensure frequent follow-up and long-term contact to prevent weight regain 1, 2