How to Lower Your BMI: Evidence-Based Steps That Work

How much can BMI change?

BMI drops by roughly 1 unit per 3 kg (6.6 lb) of weight loss for an average-height adult. To move from overweight (BMI 27) to normal (BMI 24.9), a 170 cm person would need to lose approximately 6 kg (13 lb). A realistic, sustainable rate is 0.5–1 kg per week — so that's 6–12 weeks of consistent effort.

1. Create a moderate calorie deficit

Losing 0.5 kg per week requires burning roughly 500 calories more than you consume per day. This doesn't require extreme restriction — for most people it's the difference between eating 1,800 kcal vs 2,300 kcal.

• Use a food tracking app for 2–4 weeks to establish your baseline
• Prioritise protein (1.2–1.6 g/kg body weight) — it preserves muscle and increases satiety
• Reduce ultra-processed foods and liquid calories (alcohol, sugary drinks) first
• Avoid deficits over 1,000 kcal/day — muscle loss, nutrient deficiencies, and rebound risk increase significantly

2. Add resistance training

Cardio burns calories during exercise; strength training raises your resting metabolic rate for 24–48 hours afterward. More importantly, building muscle means more of your weight loss comes from fat, not lean tissue.

2–3 sessions of full-body resistance training per week — bodyweight, free weights, or machines — is sufficient for most people. Progressive overload (gradually increasing resistance) drives continued adaptation.

3. Increase daily movement (NEAT)

Non-Exercise Activity Thermogenesis (NEAT) — the calories you burn walking, fidgeting, standing, doing chores — accounts for 200–800 kcal/day in most people. It's often more impactful than structured exercise.

• Aim for 8,000–10,000 steps per day
• Take stairs, walk to nearby destinations, stand during calls
• A standing desk can add 50–150 kcal/day burned

4. Prioritise sleep

Sleeping under 6 hours per night increases ghrelin (hunger hormone) and decreases leptin (satiety hormone), making it significantly harder to maintain a calorie deficit. Short sleepers eat an average of 300–400 extra calories per day compared to those sleeping 7–9 hours.

If you're struggling to lose weight despite a good diet, sleep is often the missing variable. Target 7–9 hours of consistent sleep, with a regular bedtime.

5. Manage chronic stress

Cortisol (the stress hormone) promotes visceral fat storage and increases appetite for calorie-dense foods. Chronic work stress, poor sleep, and emotional strain can make weight loss significantly harder even when calorie intake is controlled.

• Regular exercise itself is one of the best stress reducers
• Mindfulness and breathing techniques reduce cortisol
• Addressing the source of stress (workload, relationships) is more effective long-term than coping techniques alone

Realistic timelines

Estimates assume 0.5–1 kg/week loss rate for a 170 cm person. Individual results vary.

What doesn't work

• Crash diets under 800 kcal/day — cause rapid muscle loss, nutrient deficiencies, and almost always lead to rebound weight gain
• Spot reduction — you cannot choose where your body loses fat; it's determined genetically
• Exercise without diet changes — exercise alone rarely produces more than 0.1–0.2 kg/week loss; appetite often compensates
• Supplements claiming to "burn fat" — none have clinically meaningful effects without diet and exercise