The One Rule That Actually Matters
To lose weight, you need to consistently consume fewer calories than your body uses — a calorie deficit. Every diet approach that works (keto, intermittent fasting, calorie counting, low-carb, etc.) works because it makes a deficit easier to sustain, not because of some special metabolic trick. There is no way around this rule; there are only easier and harder ways to follow it.
Start here: use our BMR & TDEE Calculator to find your maintenance calories, then subtract 250-500 calories to set your target. That number is your actual starting point — everything else in this guide is about hitting it consistently.
Step-by-Step: Setting Up Your Deficit
How Fast Should You Lose Weight?
| Rate | Daily Deficit | Trade-off |
|---|---|---|
| 0.25 kg/week | ~250 kcal | Slower, easier to sustain, minimal muscle loss risk |
| 0.5 kg/week | ~500 kcal | Balanced pace for most people, still sustainable long-term |
| 0.75-1 kg/week | 750-1000 kcal | Faster but harder to sustain, higher risk of muscle loss and fatigue |
Faster isn't better by default. A deficit you can't sustain past 2-3 weeks does less for you long-term than a moderate one you can hold for 3 months.
Protecting Muscle While You Cut
Keep lifting
Resistance training signals your body to preserve muscle even while in a calorie deficit. Cardio-only weight loss loses more muscle for the same fat loss compared to strength training + a deficit.
Prioritise protein
Protein is the most muscle-protective macronutrient during a deficit. Check the macro breakdown on our calculator to see your target in grams.
Don't cut too aggressively
Very large deficits force your body to pull energy from muscle tissue more than a moderate deficit does. Stick to 250-500 calories below TDEE where possible.
Common Mistakes
- Underestimating portion sizes — most people underestimate calorie intake by 20-30% without tracking, even when they feel confident they know their intake.
- Overestimating exercise burn — fitness trackers and gym machines often overstate calories burned by a wide margin; don't "eat back" all exercise calories.
- Judging progress by the scale alone — water retention, sodium, and hormonal cycles shift daily weight by 1-2 kg; track weekly averages instead.
- Cutting calories too low, too fast — leads to fatigue, poor training performance, and rebound overeating.
Hit a Plateau? Do This First
Before assuming your metabolism "stalled," check the basics: has your weight actually stopped dropping over a 2-3 week average (not just one week)? Are you still weighing/logging food accurately? Has your activity level quietly dropped? Most plateaus are a tracking or adherence issue, not a metabolic one.
If a genuine plateau is confirmed after 2-3 weeks of flat weekly averages, recalculate your TDEE (it's likely dropped as you've lost weight), and either tighten your deficit slightly or take a 1-2 week maintenance "diet break" to reduce fatigue before continuing.
Frequently Asked Questions
Set Your Deficit Correctly
Calculate your TDEE and get a personalised calorie target for 0.25 kg, 0.5 kg or faster weight loss.
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