How to Lose Body Fat: The Complete Evidence-Based Guide

Introduction

Fat loss — specifically the reduction of body fat while preserving lean muscle mass — is more nuanced than the common advice of ‘eat less, move more’ suggests. The most effective and sustainable approach combines a moderate caloric deficit, high protein intake, resistance training, sleep optimisation, and stress management into a comprehensive strategy.

Step 1: Calculate Your Calorie Target

The foundation of fat loss is a sustained caloric deficit. Use our calorie calculator to determine your TDEE, then subtract 500 calories for a deficit that produces approximately 0.5kg of fat loss per week. This rate preserves lean mass while making meaningful progress.

Step 2: Prioritise Protein

Protein is the most critical dietary variable for fat loss body composition outcomes. A meta-analysis of 87 studies found higher protein intakes during caloric restriction produced significantly better lean mass preservation and greater fat loss than lower protein intakes at the same calories. Target 1.8–2.4g of protein per kilogram of body weight daily.

Step 3: Resistance Training

Resistance training during a caloric deficit is the most effective strategy for preserving lean mass. Without it, a significant portion of weight lost during caloric restriction comes from muscle. With resistance training and adequate protein, the vast majority of weight lost is fat. Train 3–4 times per week with progressive overload.

Step 4: Increase NEAT

Non-exercise activity thermogenesis (NEAT) can vary by up to 2,000 calories per day between individuals. Targeting 8,000–12,000 steps per day through walking is the most sustainable way to increase daily energy expenditure without formal exercise and without triggering compensatory appetite increases.

Step 5: Sleep and Stress

Poor sleep and elevated cortisol both directly impair fat loss and accelerate muscle breakdown. Chronic stress promotes visceral fat accumulation through cortisol-driven appetite stimulation and adipose tissue insulin resistance. Treating sleep as a performance variable and managing stress through exercise, meditation, and social connection are high-leverage interventions.