What is the body‑mass index (BMI) for a 171 cm tall, 92.5 kg adult, and what first‑line weight‑loss interventions should be advised?

BMI Calculation and Weight Loss Management

This individual has a BMI of 31.6 kg/m² (calculated as 92.5 kg ÷ 1.71² m), which classifies them as obese (Class I), and they require comprehensive lifestyle intervention for at least 6-12 months as first-line treatment. 1

BMI Classification and Risk Assessment

• The calculated BMI of 31.6 kg/m² falls into the obese category (BMI ≥30 kg/m²), which is associated with increased risk of cardiovascular disease, type 2 diabetes, certain cancers (including breast, colon, endometrium, kidney, and esophageal adenocarcinoma), and overall mortality. 1

• Waist circumference should be measured to provide additional cardiometabolic risk stratification, with cutpoints >102 cm (>40 inches) for men or >88 cm (>35 inches) for women indicating elevated risk. 1

• Screen for obesity-related comorbidities including hypertension, dyslipidemia, prediabetes/diabetes, and sleep apnea, as these require intensive management regardless of weight loss efforts. 1

First-Line Treatment: Comprehensive Lifestyle Intervention

The cornerstone of treatment is a multifactorial lifestyle intervention lasting 6-12 months that combines dietary modification, physical activity, and behavioral therapy. 1

Dietary Intervention

• Create a calorie deficit of 500-1000 kcal/day to achieve weight loss of 0.5-1 kg per week. 2

• Eliminate sugary drinks and ultra-processed foods entirely. 2

• Use portion control strategies such as meal replacements or pre-packaged meals to improve adherence. 1

• Increase consumption of fruits and vegetables while reducing high-fat and high-sugar foods. 1

Physical Activity Requirements

• Perform at least 30 minutes of moderate-intensity endurance exercise (such as brisk walking) five or more days per week, combined with strength training. 1

• For optimal weight loss maintenance, aim for 60-90 minutes of moderate-intensity activity daily or 30-45 minutes of vigorous-intensity activity. 2

• Focus on activities of daily living (walking, cycling, gardening) that match the patient's capabilities and preferences. 1

• Reduce sedentary activities such as television watching and computer use. 1

Behavioral Therapy

• Provide a minimum of 14 sessions of intensive behavioral therapy over 6 months, focusing on self-monitoring, nutrition education, and cognitive restructuring. 2

• Assess weight and lifestyle histories, including patterns of previous weight gain/loss, details of past weight loss attempts, dietary habits, family history of obesity, and medications that may affect weight. 1

Weight Loss Goals and Monitoring

• Target an initial weight loss of 10% of body weight (approximately 9.3 kg) over 6 months, which produces significant clinical benefits including reduced blood pressure and improved glycemic control. 2

• This 10% weight loss goal is achievable through lifestyle intervention alone and provides meaningful health improvements. 1, 2

• Monitor weight regularly and assess progress at 3 months; if <5% weight loss is achieved despite adherence to lifestyle interventions, consider escalation to pharmacotherapy. 1

When to Consider Pharmacotherapy

• Pharmacological weight reduction should only be considered as an adjunct to lifestyle interventions if the patient has not achieved 5-10% weight loss after 3-6 months of comprehensive lifestyle modification. 1, 2

• Medications are indicated for BMI ≥30 kg/m² (which applies here) or BMI ≥27 kg/m² with weight-related complications. 1

• Continue pharmacotherapy only if the patient loses at least 5% of initial body weight during the first 3 months or at least 2 kg during the first 4 weeks of treatment. 1

Common Pitfalls to Avoid

• Do not skip the comprehensive lifestyle intervention phase and jump directly to medications; lifestyle modification must be the foundation of treatment. 1

• Avoid focusing solely on BMI without measuring waist circumference, as this provides crucial additional risk information at this BMI level. 1

• Do not neglect screening and intensive management of cardiovascular risk factors (hypertension, dyslipidemia, diabetes), which should be addressed concurrently with weight loss efforts. 1

• Recognize that resistance exercise alone does not reduce weight effectively; endurance exercise must be the primary focus. 1