Obesity as a Disease: BMI, Waist and When to Seek Help

Weight is regulated by the brain, which defends a “set point” and increases hunger and lowers energy use after weight loss, so regain is common. Genes explain a large share of who gains weight easily. Environment adds to it: calorie-dense foods and sugary drinks, large portions, little walking in hot weather, long sitting, short sleep, stress, and some medicines (certain antidepressants, antipsychotics, steroids, insulin and others). Medical causes include an underactive thyroid, polycystic ovary syndrome, Cushing’s syndrome and rare genetic conditions. In Arab and South Asian populations the same BMI often carries more body fat, particularly around the abdomen.

Obesity has more than doubled worldwide since 1990. According to the WHO, in 2022 about 1 in 8 people in the world was living with obesity. It is common in the Gulf region, and in Saudi Arabia surveys have found that around a fifth to a third of adults are in the obesity range, depending on the survey and the year; the exact figure should be checked against the latest Ministry of Health survey.

Obesity and diabetes are major public-health priorities in the Kingdom, and weight management is part of Saudi Vision 2030 health goals. Large family meals, sweet drinks, dates and sweets in hospitality, and limited outdoor activity in hot months all play a part. A practical approach is to keep traditional foods but change portions and preparation: brown or mixed rice, grilled rather than fried, more salad and vegetable dishes, water and unsweetened coffee with a small number of dates, and indoor or evening exercise. Women and men alike may find privacy or time barriers to exercise; home-based and women-only programmes are widely available. Ask about weight-management services at your primary care clinic or hospital. Stigma about weight is common; remember that obesity is a medical condition, and seeking treatment is a sign of strength.

Your clinician measures height and weight to calculate BMI, and should also measure waist circumference or waist-to-height ratio, because two people with the same BMI can have very different amounts of belly fat. Standard WHO BMI categories for adults: 18.5 to 24.9 healthy, 25 to 29.9 overweight, 30 to 34.9 class 1 obesity, 35 to 39.9 class 2, 40 or above class 3. NICE (2025) advises lower BMI cut-offs for people of South Asian, Chinese, other Asian, Middle Eastern, Black African or African-Caribbean background: overweight from 23 and obesity from 27.5, because health risk begins at lower BMI. For waist, the International Diabetes Federation uses 94 cm or more for men and 80 cm or more for women for Arab populations; a waist-to-height ratio of 0.5 or more (waist at least half of height) suggests increased risk. BMI can mislead in very muscular people, older adults with muscle loss, and during pregnancy. Then the important step is to look for related conditions: blood pressure, blood sugar (HbA1c), cholesterol and triglycerides, liver tests with a liver scan or elastography, sleep apnoea screening, thyroid and other tests as needed, and screening for depression and disordered eating.

Small, sustainable habits matter more than short bursts of effort.

• Move more: aim for at least 150 minutes of moderate activity a week (brisk walking, swimming, cycling), plus muscle-strengthening exercise twice a week. Indoor malls and evening walks are options in hot weather.

• Sleep 7 to 9 hours; short or poor sleep raises appetite. Ask about snoring and sleep apnoea.

• Cut long sitting: stand or walk for a few minutes every hour.

• Weigh yourself regularly, measure your waist monthly, and focus on health measures too (energy, blood pressure, sugar, fitness).

• Look at stress, emotional eating and mood; psychological support or behavioural therapy helps many people.

• Stop smoking if you smoke; do not use diet pills or “detox” or herbal slimming products, which are unproven and sometimes dangerous to the liver.

Which diet is best is the one you can follow for years. See the separate article on weight-loss diets for the evidence. These principles are common to all successful plans.

• Build meals around vegetables, fruit, legumes, whole grains, fish, eggs, poultry, yoghurt and olive oil, with fewer sugary drinks, sweets, fried foods and ultra-processed snacks.

• Replace sugary drinks (soft drinks, sweetened juice and sweet coffee drinks) with water, unsweetened tea or coffee, or laban without sugar.

• Use smaller plates, eat slowly, and share large restaurant portions; large shared dishes such as kabsa are easier to overeat from, so serve yourself a portion first.

• Do not skip meals and then overeat; plan regular meals and healthy snacks (fruit, nuts in small portions, yoghurt).

• Realistic aims: a loss of 5 to 10% of your body weight over 6 months is a meaningful, health-improving goal for most people. Faster is not better.

• Very low calorie plans below about 800 kcal a day should only be used with medical supervision.

Do not use words such as “cheat day” or “good and bad foods”; flexible, kind eating habits are easier to keep.

Medicines for weight are used together with diet and activity, not instead of them. Your doctor decides who is eligible and watches for side effects.

• Current guidelines consider anti-obesity medicines for adults with BMI 30 or more, or 27 or more (lower in some ethnic groups) with a weight-related condition. Newer GLP-1-based medicines produce larger average weight loss than older drugs; see our article on GLP-1 and weight.

• Some medicines you already take may cause weight gain; never stop them yourself, but ask your doctor whether alternatives exist.

• Treatment of related problems: blood pressure, diabetes, cholesterol, sleep apnoea and fatty liver are treated alongside weight.

• Only use medicines from licensed pharmacies approved by the Saudi Food and Drug Authority (SFDA); avoid unregulated products sold online or on social media.

Procedures are for people with more severe obesity, or with obesity-related disease, when other treatment has not given enough benefit.

• Metabolic-bariatric surgery (for example sleeve gastrectomy or gastric bypass) is generally considered at BMI 35 or more, or 30 or more with diabetes or other serious complications (lower thresholds apply for Asian populations), and gives the largest and most durable weight loss. See our bariatric surgery article.

• Endoscopic options such as intragastric balloons or endoscopic sleeve are available in some centres for selected patients, with smaller average weight loss.

• Pre-procedure assessment includes nutrition, psychological and medical review and lifelong follow-up with vitamin monitoring.

The Lancet Diabetes & Endocrinology Commission on the definition and diagnosis of clinical obesity (2025) recommends confirming excess fat using BMI plus waist measures (or direct fat measurement), then assessing organ function and daily function to decide whether the obesity is “clinical”. The 2022 Canadian guideline (Obesity Canada) and the 2025 ADA Standards of Care frame obesity as a chronic disease to be treated with long-term, patient-centred care, not blame. Weight loss of about 5% improves blood sugar, blood pressure and liver fat; 7 to 10% is linked with improvement of inflammation in metabolic dysfunction-associated steatotic liver disease (MASLD, formerly “fatty liver”) and 10% or more with possible fibrosis regression, according to AASLD guidance (2023) and cohort data. Excess body weight is linked to an increased risk of at least 13 cancers, including colorectal, liver, oesophageal, pancreatic and gallbladder cancer. Weight bias and shame are themselves harmful and are associated with avoiding care and worse health. Modern treatment includes lifestyle support, anti-obesity medicines (see the GLP-1 article) and metabolic-bariatric surgery for suitable patients.

Obesity is manageable but usually lifelong, like high blood pressure or diabetes: when treatment stops, weight tends to return. The best results come from a long-term plan with regular follow-up. Even modest, sustained weight loss lowers the chance of type 2 diabetes, helps fatty liver and joints, improves mood and sleep, and can reduce the number of medicines needed. Setbacks and regain are part of the condition, not personal failure.

• What is my BMI and waist measurement, and what do they mean for my health?

• Should I be tested for diabetes, fatty liver, high blood pressure, cholesterol or sleep apnoea?

• Is any of my medicine contributing to weight gain?

• What weight-loss goal is realistic for me?

• Am I a candidate for medicines or bariatric surgery?

This guide comes from the Saudi Gastroenterology Association (SGA) patient library, prepared by the Approved for publication by SGA; individual clinician review is ongoing. Last reviewed: 2026-04-24. It is for education and does not replace your doctor's advice.