How to lose weight — and keep it off.
Sustainable weight loss comes from one thing: a consistent calorie deficit — eating less than your body burns. Everything else is detail. Here is how to do it right.
Optimal deficit
250–500 kcal/day
Sustainable fat loss pace
Expected rate
0.25–0.5 kg/week
Without muscle loss
Protein target
1.6–2.2 g/kg
Preserve muscle while cutting
The science of weight loss
Your body weight is governed by energy balance: calories in versus calories out. When you consume fewer calories than your body expends — your Total Daily Energy Expenditure (TDEE) — the deficit must be covered by stored energy. Most of that stored energy is body fat.
One kilogram of body fat contains roughly 7,700 calories of stored energy. A sustained daily deficit of 500 calories therefore produces approximately 0.45 kg of fat loss per week. This is a reliable, predictable relationship — the reason calorie tracking is the most evidence-backed approach to weight loss.
The challenge is that your TDEE is not fixed. As you lose weight, your body requires fewer calories to function, so the same calorie intake that produced a deficit at the start of your journey will produce a smaller deficit — or none at all — months later. This is the root cause of most weight loss plateaus.
Calorie deficit drives fat loss
No deficit = no fat loss. Your body burns stored fat when dietary calories fall short of energy needs. The size of the deficit controls the speed of loss.
Protein preserves muscle
High protein intake (1.6–2.2 g/kg body weight) signals your body to preserve lean tissue while burning fat. Less muscle loss means a higher resting metabolism.
TDEE falls as you lose weight
Smaller body = lower energy needs. Your calorie target must be updated every few weeks as your weight changes, or progress will stall.
Consistency beats perfection
Weight loss is a weekly average game, not a daily one. One high-calorie day does not undo a week of deficit. Tracking long-term trends matters more than any single number.
How to set your weight loss calorie goal
Your daily calorie target for weight loss is your TDEE minus your chosen deficit. Here is how to choose a deficit that fits your goal pace:
Best for those close to their goal weight, people who train hard and need to preserve performance, or anyone who finds larger deficits unsustainable. Slower progress but very little muscle loss risk.
The sweet spot for most people. Large enough to produce meaningful weekly progress on the scale, small enough to preserve muscle and energy levels. Adjust based on 2–3 weeks of real weight data.
Appropriate only for those with significant excess weight to lose and under professional guidance. Increases risk of muscle loss, fatigue, and nutrient deficiencies. Requires very high protein intake to compensate.
These are starting estimates. Always validate against 2–3 weeks of real weight data and adjust your target by ±100–200 kcal if results are not matching expectations.
Nutrition principles for sustainable fat loss
The calorie deficit is the non-negotiable. Within that deficit, what you eat affects hunger, energy, muscle retention, and long-term adherence. These principles make weight loss more effective and sustainable.
Prioritise protein at every meal
Protein is the most satiating macronutrient and has the highest thermic effect — your body burns more calories digesting it than carbs or fat. Aim for 1.6–2.2 g per kg of body weight per day. Distribute it across meals rather than loading it into one sitting.
Keep carbs and fat to your preference
Both low-carb and low-fat approaches produce similar fat loss results when protein and total calories are equated. Pick the distribution that keeps you fullest and most consistent. Neither is magic — total calories are what drives the deficit.
Choose high-volume, lower-calorie foods
Foods with a high water and fibre content — vegetables, fruits, legumes, lean proteins — provide more volume per calorie, making it easier to feel full within your calorie budget. Ultra-processed, calorie-dense foods do the opposite.
Track weekly averages, not daily perfection
Your weight fluctuates daily due to water retention, glycogen, digestion, and hormones. What matters is the trend over 1–2 weeks. One high-calorie day within an otherwise controlled week will not meaningfully affect fat loss.
Keep resistance training in your routine
Lifting weights while in a calorie deficit is the most effective way to preserve muscle mass. More muscle means a higher resting metabolic rate — making it easier to maintain your deficit and keep weight off long-term.
How 2BIB helps you lose weight
The biggest reason weight loss plans fail is not lack of willpower — it is using a static calorie goal that does not update as your body changes. 2BIB is built specifically to solve this.
Personalised TDEE calculation
2BIB calculates your real TDEE from your height, weight, age, sex, and activity level using the Mifflin-St Jeor equation — not a generic population average. Your calorie deficit is built on your actual energy needs.
Automatic target recalibration
As you lose weight, your TDEE falls. 2BIB compares your actual weight progress against your milestone targets and automatically adjusts your daily calorie goal when the two diverge — keeping your deficit accurate without any manual recalculation.
Macro tracking with protein focus
Log every meal with 2BIB's AI food scanner or barcode lookup. See your protein, carb, and fat intake in real time alongside your calorie total — so you can hit your protein target while staying within your deficit.
Weight progress vs. milestones
Log your weight daily or weekly and 2BIB shows you how your actual rate of loss compares to your goal pace. When you're on track, you see it. When you're off track, your calorie target updates.
Plain-English weekly action plan
Every week, 2BIB generates a simple summary of your progress and tells you exactly what to adjust — no nutrition degree required. Just follow the plan and let the app do the maths.
Start losing weight with a goal that actually adapts
Enter your metrics once. 2BIB sets your personalised calorie deficit and keeps it calibrated as you progress — so plateaus become a diagnostic, not a dead end.
Common weight loss mistakes to avoid
Setting too large a deficit
Eating 1,000+ kcal below TDEE often causes rapid scale losses — but much of that is water and muscle, not fat. A 250–500 kcal deficit is more sustainable and protects your metabolism.
Ignoring protein
Cutting calories without eating enough protein leads to significant muscle loss alongside fat loss. Less muscle means a lower resting metabolic rate — making the deficit harder to maintain over time.
Never updating your calorie goal
A calorie target set at 90 kg is wrong at 80 kg. As you lose weight, your TDEE decreases. Your daily goal must be recalculated regularly or your deficit will shrink to nothing.
Giving up after a bad week
Weight fluctuates daily by 1–3 kg due to water, glycogen, and digestion. A week where the scale does not move — or moves up — does not mean you are not losing fat. Look at the 2–4 week trend.
Dramatically under-eating
Very low calorie diets (below 1,200 kcal for women, 1,500 kcal for men) trigger metabolic adaptation, muscle loss, and nutrient deficiencies. They also have the highest long-term failure rates due to unsustainability.
Only relying on cardio
Cardio burns calories but has a limited effect on body composition without resistance training. Lifting weights preserves muscle during a deficit, which keeps your metabolic rate higher as you lose weight.
Frequently asked questions
How many calories should I eat to lose weight?
Eat 250–500 calories below your TDEE. Your TDEE depends on your weight, height, age, sex, and activity level. A 500-calorie daily deficit typically produces around 0.45 kg (1 lb) of fat loss per week. Recalculate every 4–6 weeks as your weight changes.
How fast should I lose weight?
A sustainable rate is 0.25–0.5 kg (0.5–1 lb) per week. Faster loss is possible but increases muscle loss risk and is harder to sustain. Slower rates are absolutely fine — consistency matters more than pace.
What is the difference between fat loss and weight loss?
Weight loss is total body mass reduction (fat, muscle, water, glycogen). Fat loss specifically means reducing body fat tissue. A high-protein diet plus a moderate calorie deficit maximises fat loss while minimising muscle loss.
Why does weight loss slow down over time?
As you lose weight, your TDEE decreases — smaller body = lower energy needs. The same calorie intake that created a deficit initially produces a smaller deficit later. Recalculate your TDEE every 4–8 weeks, or use an adaptive app like 2BIB that does it automatically.
Do I need to track macros to lose weight?
No. A calorie deficit alone drives fat loss. But tracking protein (targeting 1.6–2.2 g/kg body weight) significantly improves body composition by preserving muscle. Tracking all macros gives the most complete picture.
How does 2BIB help with weight loss?
2BIB calculates your personalised TDEE, sets your calorie deficit target, tracks your food and weight daily, and automatically adjusts your calorie goal as you lose weight. When your weight progress deviates from your milestone, your target recalibrates — so your deficit stays accurate without any manual work.
Your weight loss target, always accurate.
2BIB calculates your calorie deficit from your real TDEE and automatically recalibrates as you lose weight — so you never plateau because of a stale number.
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