IM14.1-14 | Obesity — Glossary

Screening test for Cushing syndrome: 1 mg oral dexamethasone given at 11 PM, cortisol measured at 8 AM — cortisol <50 nmol/L = normal (Cushing excluded); cortisol >138 nmol/L = failed suppression (Cushing probable). False positives occur with depression, alcoholism, obesity, and enzyme-inducing drugs.

A standardised dietary assessment method in which the patient is asked to recall all foods and beverages consumed in the previous 24 hours; provides a practical starting estimate of dietary intake for clinical purposes; subject to recall bias and day-to-day variation.

The minimum weight reduction (5% of total body weight) that produces measurable clinical benefits: reduced blood pressure, improved insulin sensitivity, lower triglycerides, reduced hepatic fat, and improved OSA severity; used as the pharmacotherapy efficacy benchmark — if <5% loss at 3 months on optimal dose, reassess.

A structured brief obesity counselling model: Ask (seek permission), Assess (BMI, waist, comorbidities, readiness), Advise (personalised non-judgmental health risk communication), Agree (collaborative SMART goal-setting), Assist (resources, referral, follow-up); applicable in any clinical setting within 5–10 minutes.

Velvety, hyperpigmented, thickened skin in body folds (neck, axillae, groin) that is a reliable cutaneous marker of insulin resistance and hyperinsulinaemia; bilateral and symmetrical in metabolic acanthosis; unilateral or rapidly progressive may suggest paraneoplastic cause.

Cytokines and signalling proteins secreted by adipose tissue, including leptin (satiety signal), adiponectin (insulin sensitiser), resistin, and pro-inflammatory cytokines (TNF-α, IL-6); dysregulated in obesity, contributing to systemic inflammation and insulin resistance.

Pathological adipose tissue function characterised by adipocyte hypertrophy, hypoxia, macrophage infiltration, and chronic inflammatory state; the mechanistic basis for the systemic complications of obesity including insulin resistance, dyslipidaemia, and cardiovascular disease.

Antibodies against thyroid peroxidase, the enzyme responsible for thyroid hormone synthesis; marker of autoimmune thyroiditis (Hashimoto's); their presence in subclinical hypothyroidism (elevated TSH with normal fT4) indicates higher risk of progression to overt hypothyroidism and supports initiation of levothyroxine.

The number of apnoeic and hypopnoeic episodes per hour of sleep measured on polysomnography; grading: normal <5, mild OSA 5–14, moderate 15–30, severe >30 events/hour; guides treatment decisions (CPAP for moderate-severe, lifestyle for mild).

Indications for bariatric surgery using Asian-Indian BMI cut-offs: BMI ≥37.5 kg/m² without comorbidities; BMI ≥32.5 kg/m² with at least one major obesity-related comorbidity (T2DM, hypertension, OSA, NAFLD); BMI ≥27.5 kg/m² with poorly controlled T2DM (emerging metabolic surgery indication).

An autosomal recessive ciliopathy syndrome characterised by childhood obesity, retinal dystrophy (night blindness leading to visual loss), polydactyly, renal anomalies, intellectual disability, and hypogonadism; caused by mutations in BBS genes.

Surgical procedures to achieve substantial, sustained weight loss in severely obese patients; indications in India: BMI ≥37.5 kg/m² without comorbidities or BMI ≥32.5 with major comorbidities; procedures include sleeve gastrectomy and Roux-en-Y gastric bypass; can achieve T2DM remission.

Weight (kg) divided by height squared (m²); the primary population-level index of adiposity; Asian-Indian cut-offs are overweight ≥23 kg/m² and obese ≥25 kg/m², lower than Western WHO cut-offs (overweight ≥25, obese ≥30).

The difference between energy intake and total daily energy expenditure; a sustained deficit of 500–750 kcal/day below TDEE produces approximately 0.5–0.75 kg/week of weight loss and 4–8 kg over 6 months; the dietary target in structured obesity management.

Excess adipose tissue deposited in the abdominal region and around visceral organs; metabolically more harmful than subcutaneous fat due to higher pro-inflammatory cytokine output and direct portal delivery of free fatty acids to the liver.

Falsely elevated blood pressure reading caused by using a standard-sized cuff on a large arm (circumference >34 cm); the standard bladder under-cuffs the arm, increasing the pressure required to occlude the brachial artery and producing an erroneously high reading; corrected by using a large-adult or thigh cuff.

A secondary cause of obesity resulting from chronic glucocorticoid excess; characterised by central obesity, moon face, buffalo hump, wide purple striae, proximal myopathy, hypertension, and hyperglycaemia; screened for with 24-h urinary free cortisol or overnight 1 mg dexamethasone suppression test.

A post-bariatric (especially RYGB) complication in which rapid gastric emptying of hyperosmolar contents into the small intestine triggers early dumping (vasomotor symptoms: flushing, palpitations, diarrhoea within 30 min of eating) or late dumping (reactive hypoglycaemia 1–3 h after eating); managed by avoiding large meals, high-sugar foods, and liquid calories during meals.

A validated self-report questionnaire assessing daytime somnolence across 8 situations; scores range 0–24; score ≥10 suggests excessive daytime sleepiness warranting investigation for obstructive sleep apnoea; widely used as a screening tool for OSA in clinical practice.

A class of anti-obesity and anti-diabetic drug that mimics glucagon-like peptide-1; reduces appetite, slows gastric emptying, and promotes satiety; examples include liraglutide and semaglutide; associated with significant weight loss and cardiovascular benefit; first-line pharmacotherapy for obesity in patients with cardiometabolic risk.

A calculated index of insulin resistance: [fasting insulin (μU/mL) × fasting glucose (mmol/L)] / 22.5; values >2.5 indicate insulin resistance; not diagnostic of diabetes but useful to quantify metabolic risk and monitor response to lifestyle intervention.

Obesity resulting from lesions or injury to the hypothalamic appetite-regulation centres (tumours such as craniopharyngioma, trauma, surgery, radiotherapy); often associated with other hypothalamic hormone deficiencies and marked hyperphagia with reduced satiety.

Fasting plasma glucose 100–125 mg/dL (5.6–6.9 mmol/L); a pre-diabetic state with elevated risk of progressing to type 2 diabetes; warrants lifestyle intervention (weight loss, dietary modification, increased physical activity) and repeat FPG or OGTT in 3–6 months.

A state in which normal concentrations of insulin produce a subnormal biological response in target tissues (skeletal muscle, liver, adipose tissue); central to the pathogenesis of type 2 diabetes, metabolic syndrome, and PCOS; driven by visceral adiposity, free fatty acid overflow, and adipokine dysregulation.

The most commonly performed bariatric procedure; 80% of the greater curvature of the stomach is removed laparoscopically, creating a sleeve-shaped tube; predominantly restrictive mechanism plus reduced ghrelin secretion; expected 25–30% total body weight loss; T2DM remission 50–60%; fewer nutritional complications than RYGB.

A peptide hormone secreted by adipocytes in proportion to fat mass; acts on hypothalamic neurons to suppress appetite and increase energy expenditure; leptin resistance (not deficiency) is present in most common obesity, characterised by high leptin levels that fail to produce satiety.

A rare autosomal recessive monogenic form of severe early-onset obesity; serum leptin is markedly elevated because the receptor is non-functional; presents in infancy with constant hyperphagia; distinguished from leptin deficiency by elevated (not low) serum leptin.

A GLP-1 receptor agonist approved for obesity (Saxenda® 3.0 mg/day) and T2DM (Victoza® 1.2–1.8 mg/day); subcutaneous once-daily injection; ~8% mean weight loss at 56 weeks (SCALE trial); cardiovascular benefit in T2DM (LEADER trial); contraindicated in personal/family history of medullary thyroid carcinoma or MEN2.

The most common monogenic cause of severe childhood obesity, accounting for 2–5% of cases; autosomal dominant with variable penetrance; caused by loss-of-function mutation reducing satiety signalling in the hypothalamic leptin-melanocortin pathway; setmelanotide is approved for treatment.

A cluster of cardiometabolic risk factors; by IDF 2005 criteria, defined as central obesity (mandatory, using ethnic-specific waist cut-offs) plus any 2 of: fasting TG ≥150 mg/dL, HDL <40/50 mg/dL, BP ≥130/85 mmHg, fasting glucose ≥100 mg/dL.

A semiquantitative scoring system for hirsutism in women; assesses terminal hair growth in 9 androgen-sensitive body areas (upper lip, chin, chest, upper abdomen, lower abdomen, upper arm, thigh, upper back, lower back); total score ≥8 indicates hirsutism (hyperandrogenism).

An evidence-based person-centred counselling technique for behaviour change; key principles are expressing empathy, developing discrepancy, rolling with resistance, and supporting self-efficacy; demonstrated to produce better weight loss outcomes than traditional didactic dietary advice in obesity management.

Accumulation of fat in hepatocytes (steatosis) in the absence of significant alcohol consumption; strongly associated with central obesity and insulin resistance; can progress to non-alcoholic steatohepatitis (NASH), cirrhosis, and hepatocellular carcinoma; now often termed metabolic-associated fatty liver disease (MAFLD).

Chronic hypoventilation and daytime hypercapnia (PaCO2 >45 mmHg) in obese patients (BMI ≥30) not explained by other causes; also called Pickwickian syndrome; can progress to pulmonary hypertension and right heart failure.

Repeated episodes of upper airway obstruction during sleep, causing apnoeas and hypopnoeas; strongly associated with pharyngeal fat deposition in obesity; leads to nocturnal hypoxia, sympathetic activation, daytime somnolence, hypertension, and cardiovascular complications.

A pancreatic and gastric lipase inhibitor that prevents digestion and absorption of ~30% of dietary fat; dosed 120 mg three times daily with meals; produces ~2.5–3.5 kg additional weight loss vs placebo; side effects are GI (steatorrhoea, faecal urgency) and are worse with high-fat meals; impairs fat-soluble vitamin absorption — supplement separately.

Ultrasound finding of ≥20 follicles of 2–9 mm diameter per ovary, or ovarian volume >10 mL per ovary (in the absence of a dominant follicle or corpus luteum); one of the three Rotterdam criteria for PCOS; can be present without clinical or biochemical hyperandrogenism.

A syndromic form of obesity caused by loss of paternal 15q11-q13 gene expression; presents with neonatal hypotonia and poor feeding followed by severe hyperphagia, rapid weight gain, intellectual disability, short stature, and hypogonadism; growth hormone therapy is used.

Weakness of the proximal limb girdle muscles (shoulder and hip girdle); clinically tested by asking the patient to rise from a chair without using their hands, or to raise both arms above the head; an important red-flag sign of Cushing syndrome and also seen in hypothyroidism, inflammatory myopathies, and osteomalacia.

Diagnostic criteria for polycystic ovary syndrome requiring 2 of 3: (1) oligo- or anovulation; (2) clinical or biochemical hyperandrogenism (Ferriman-Gallwey ≥8 or elevated free testosterone); (3) polycystic ovarian morphology on ultrasound (≥20 follicles per ovary 2–9 mm or ovarian volume >10 mL); after excluding other androgen-excess causes.

A bariatric procedure creating a small gastric pouch (~30 mL) anastomosed to the distal small bowel, bypassing the stomach remnant, duodenum, and proximal jejunum; weight loss by restriction + malabsorption + dramatic GLP-1 increase; expected 30–35% total body weight loss at 2 years; T2DM remission 60–80%.

A GLP-1 receptor agonist approved for obesity (Wegovy® 2.4 mg weekly) and T2DM (Ozempic® 0.5–2 mg weekly); the STEP-1 trial demonstrated ~15% mean total body weight loss at 68 weeks — the largest pharmacological weight loss demonstrated to date; also with cardiovascular benefit (SELECT trial).

Five stages of readiness to change a health behaviour: pre-contemplation, contemplation, preparation, action, maintenance; matching the counselling intervention to the patient's current stage improves engagement and outcomes compared to providing uniform advice.

A behavioural framework describing the readiness to change unhealthy behaviours: pre-contemplation (not yet aware/ready), contemplation (aware but ambivalent), preparation (planning to change soon), action (currently making changes), maintenance (sustaining change >6 months); used to match counselling intervention to patient readiness.

Drinks with added caloric sweeteners (colas, fruit juices with added sugar, energy drinks, sweet lassi, sweet chai); provide liquid calories with minimal satiety effect; fructose in SSBs drives hepatic de novo lipogenesis, contributing to NAFLD and dyslipidaemia; reducing or eliminating SSBs is among the highest-yield dietary interventions in obesity management.

Normalisation of blood glucose to pre-diabetic or non-diabetic levels after bariatric surgery, independent of weight loss alone; most complete after RYGB (60–80%) due to GLP-1 surge from undigested food reaching the distal ileum; also occurs after sleeve gastrectomy (50–60%); a distinct mechanistic benefit beyond weight reduction.

Foods manufactured through intensive industrial processing, typically high in energy density, added sugars, unhealthy fats, and additives, with little intact nutritional structure; primary dietary driver of the global obesity epidemic; disrupt satiety signalling disproportionately to their caloric content.

Anthropometric measure of central (abdominal) obesity; action thresholds for Asian Indians are ≥90 cm in men and ≥80 cm in women; correlates better with visceral fat mass and cardiometabolic risk than BMI alone.

Social stereotyping, discrimination, and prejudice directed at individuals because of their weight; documented in healthcare settings as clinician bias, leading to shorter consultations, dismissive attitudes, and avoidance of healthcare by patients with obesity; associated with worse health outcomes; counteracted by person-first language and non-judgmental counselling practice.