How to Lose Weight: Evidence-Based Starting Point for UK Adults

Weight loss advice is everywhere, but the core evidence base for what actually works is relatively consistent. This article summarises what the evidence shows about the essential components of effective weight loss and how to structure a starting approach.

Step 1: Establish Your Calorie Target

Estimated Total Daily Energy Expenditure (TDEE): This is the number of calories you burn daily across all activities. For a rough estimate:

Sedentary adults (desk job, minimal exercise): BMR × 1.2
Lightly active (1–3 exercise sessions/week): BMR × 1.375
Moderately active (3–5 sessions/week): BMR × 1.55
Very active (6–7 hard sessions/week): BMR × 1.725

BMR (Basal Metabolic Rate) can be estimated using the Mifflin-St Jeor equation:

Men: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
Women: (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161

Creating a deficit: NICE NG238 recommends an energy deficit of approximately 600 kcal/day below estimated energy requirements for most adults with obesity — producing approximately 0.5–0.75kg/week weight loss.

Important: Do not drop below 1,200 kcal/day for women or 1,500 kcal/day for men without medical supervision. Very low calorie diets accelerate lean mass loss and metabolic adaptation.

Step 2: Set Protein Target

Protein is the most critical macronutrient during weight loss for two reasons:

Lean mass preservation: Protein provides amino acid substrate for muscle protein synthesis to continue during caloric deficit. Without adequate protein, a significant proportion of weight lost is lean mass rather than fat — reducing metabolic rate and strength.

Satiety: Protein is the most satiating macronutrient. Higher protein intake significantly reduces spontaneous calorie intake through GLP-1, PYY, and CCK release.

Target: 1.6–2.2g protein per kg bodyweight per day. Distribute across 3–4 meals, each containing approximately 25–40g protein.

Practical sources: Chicken, fish (especially white fish and salmon), eggs, Greek yoghurt, cottage cheese, legumes (lentils, chickpeas, black beans), tofu and tempeh.

Step 3: Structure Your Approach to Food

What to Eat More of

Non-starchy vegetables: At least 5 portions/day; high volume and fibre per calorie; excellent for satiety within a deficit
Lean proteins: See above; should constitute 30–35% of calorie intake ideally
Whole grains: Brown rice, oats, quinoa, wholegrain bread and pasta — higher fibre, slower glucose release, more satiating than refined equivalents
Legumes: Lentils, chickpeas, kidney beans — protein + fibre combination with low energy density
Fruit: Moderate amounts; high fibre, low energy density (except dried fruit and juice)

What to Reduce

Ultra-processed foods: Associated with passive overconsumption of 500 kcal/day in RCTs. Minimise food products with >5 ingredients, additives, preservatives, and high palatability without nutritional density
Liquid calories: Sugary drinks, fruit juices, alcohol — calories consumed in liquid form produce less satiety than equivalent solid food calories
Refined carbohydrates: White bread, white rice, pastries — rapidly digested, shorter satiety duration, easier to overconsume than whole food equivalents
Calorie-dense snacks: Crisps, biscuits, chocolate bars — typically low in protein and fibre, high in energy density

Calorie Tracking

Calorie awareness is the most evidence-supported dietary behaviour for weight management. A 2019 systematic review found mobile dietary self-monitoring produced significantly greater weight loss than control groups.

Options:

MyFitnessPal or Cronometer — free apps; calorie and protein tracking
NHS Weight Loss Plan app — free; evidence-based structure
Manual food diary — paper-based; lower barrier than app-based tracking

Tracking does not need to be permanent — many people use it for 8–12 weeks to develop accurate portion awareness, then maintain without tracking.

Step 4: Include Resistance Training

Resistance training during weight loss is the most evidence-supported strategy for preserving lean mass. A 2018 Obesity Reviews meta-analysis found resistance training significantly reduced lean mass loss compared to calorie restriction alone.

Minimum effective dose: 2–3 resistance training sessions per week. Exercises that engage large muscle groups:

Squats and lunges (quadriceps, glutes, hamstrings)
Deadlifts (hamstrings, glutes, back)
Push-ups and bench press (chest, triceps, shoulders)
Rows and lat pulldowns (back, biceps)
Overhead press (shoulders, triceps)

Gym membership is not required — bodyweight exercises (press-ups, squats, lunges, rows with a resistance band) provide adequate stimulus for beginners.

Step 5: Address Daily Activity (NEAT)

Non-Exercise Activity Thermogenesis (NEAT) — the energy expended in daily movement outside formal exercise — varies by 350–750 kcal/day between sedentary and active individuals of similar size.

For most people, increasing daily step count is the simplest, most sustainable intervention:

Aiming for 8,000–12,000 steps/day adds approximately 200–500 kcal/day to energy expenditure
Walking is low-intensity, requires no recovery, and can be accumulated throughout the day
UK adults average approximately 5,000–6,000 steps/day — increasing to 10,000 is achievable for most people

Step 6: Monitor Progress Appropriately

Weigh yourself weekly, not daily: Body weight fluctuates 1–3kg daily due to water retention, glycogen, and gut content. Weekly averages provide meaningful trend data without day-to-day noise.

Track multiple metrics:

Scale weight (weekly average)
Waist circumference (monthly)
Progress photographs (monthly)
How clothes fit

Scale weight alone can be misleading if muscle is being gained simultaneously with fat loss — body circumference measurements and photographs provide additional information.

When Progress Stalls

Weight loss plateaus are expected and result from:

Reduced energy expenditure with lower body weight — a lighter body burns fewer calories at rest and during activity
Metabolic adaptation — reduced thyroid output and NEAT during sustained deficit
Increased logging inaccuracy — portion size creep is common over time

Response options:

Recalculate TDEE for new (lower) body weight and adjust target
Increase physical activity rather than further reducing food intake
Take a diet break (2 weeks at maintenance calories) — may partially restore metabolic rate and improve subsequent adherence
Review logging accuracy — food weighing rather than estimating

NHS Support Options

UK residents have access to evidence-based support:

NHS Better Health: free online resources, apps, and NHS Weight Loss Plan (nhs.uk/better-health/lose-weight)
GP referral to Tier 2 weight management services: Group or individual behaviour change support; available in most areas
Tier 3 specialist obesity services: For BMI ≥35 with obesity-related conditions
NHS Low Calorie Diet Programme: For eligible adults with type 2 diabetes; includes total diet replacement phase

Disclaimer: This article is for informational and educational purposes only. For personalised guidance, consult your GP or a Registered Dietitian. If you have medical conditions including cardiovascular disease, diabetes, or eating disorder history, seek medical advice before starting any weight loss programme.