The step-by-step system for turning your TDEE number into a fat loss plan that actually lasts
You've calculated your TDEE. You have a number. Now what?
Most people at this point do one of two things: they either ignore the number entirely, or they subtract 500 calories and start eating that amount โ forever โ regardless of what their body actually does in response. Neither approach leads anywhere good.
Building a sustainable fat loss plan from a TDEE calculation is a process, not a single step. This guide walks through every stage of that process: what a 500-calorie deficit really means, how to implement it practically, how to know if it's working, and how to adjust when it inevitably needs recalibrating.
The 500-calorie deficit has become the standard recommendation in weight loss nutrition for a reason grounded in physiology. One kilogram of body fat contains approximately 7,700 calories of stored energy. A daily deficit of 500 calories produces a weekly deficit of 3,500 calories โ or roughly 0.45 kg (1 lb) of fat per week.
This rate โ approximately 0.5 kg/week โ has been identified across multiple research trials as sitting in a productive sweet spot:
Use a reliable TDEE calculator with your current weight, height, age, sex, and activity level. This is your maintenance number โ the calories you need to eat to hold your current weight. Be honest about activity level; overestimating here is the single most common reason calorie targets fail.
Your starting daily calorie target = TDEE โ 500. This is where you begin. Example: if your TDEE is 2,350 kcal, your starting deficit target is 1,850 kcal/day. Note: if this puts you below 1,200 kcal (women) or 1,500 kcal (men), use a smaller deficit โ these are physiological floors below which health risks increase significantly.
Before assigning calories to carbohydrates and fat, determine your protein target: 1.6โ2.0 g per kg of body weight per day. Multiply by 4 (calories per gram of protein) to find how many calories protein will consume from your daily budget. This is non-negotiable โ protein is what protects your muscle mass during a deficit.
Set fat at minimum 0.7โ1.0 g/kg/day (essential for hormone function). Allocate remaining calories to carbohydrates. Most people find performance and adherence easiest when carbohydrates are not excessively restricted โ prioritise them around training sessions.
Use a food scale for at least the first 2โ4 weeks. Volume estimation errors of 20โ40% are common even for experienced trackers. Use a consistent calorie tracking app. Weigh yourself daily first thing in the morning and calculate a 7-day rolling average โ this smooths out water retention fluctuations and gives a real signal.
Compare your weekly weight average to the previous week. If losing 0.3โ0.7 kg/week: your plan is working โ continue. If not losing or gaining: your real TDEE is lower than estimated โ reduce intake by 100โ150 kcal and re-evaluate in 2 more weeks. Don't panic-reduce by 500+ kcal in one adjustment.
| TDEE | Deficit Target | Protein (75kg person) | Fat (min) | Carbs |
|---|---|---|---|---|
| 1,800 kcal | 1,300 kcal | 120โ150 g | 53โ75 g | Remaining |
| 2,200 kcal | 1,700 kcal | 120โ150 g | 53โ75 g | Remaining |
| 2,600 kcal | 2,100 kcal | 120โ150 g | 53โ75 g | Remaining |
| 3,200 kcal | 2,700 kcal | 120โ150 g | 53โ75 g | Remaining |
Here's what nobody tells you when they hand you a calorie target: the body adapts. Two interacting mechanisms work against you as a fat loss phase progresses:
As you lose weight, your body has less mass to maintain, and your TDEE drops accordingly. A person who started at 90 kg with a TDEE of 2,500 kcal might have a TDEE of 2,300 kcal after losing 8 kg โ even if nothing else changed. Their 500-calorie deficit has shrunk to 300 calories without them adjusting anything.
Beyond the weight-driven reduction, the body responds to sustained caloric restriction by reducing NEAT (unconscious movement decreases), lowering thyroid hormone output slightly, and becoming more efficient at extracting energy from food. This metabolic adaptation can reduce TDEE by an additional 100โ300 kcal/day compared to what weight loss alone would predict.
The practical response: recalculate your TDEE every 4โ6 weeks using your current body weight and reset your calorie target accordingly. This is not failure โ it's the expected biology of fat loss. Planning for it is what separates sustainable programmes from ones that plateau and collapse.
The counterintuitive tool for breaking a plateau is sometimes a diet break โ 1โ2 weeks of eating at estimated maintenance โ rather than a deeper cut. Research on diet breaks shows they partially restore NEAT and reduce the metabolic adaptation effect, allowing the subsequent deficit phase to be more effective.
A structured programme might look like:
Below certain calorie thresholds, the risks of nutrient deficiency, severe muscle loss, hormonal disruption, and metabolic adaptation become too large to justify a faster rate of fat loss. These floors represent points where you should switch strategies โ add more activity rather than removing more food:
| Population | Minimum Calorie Floor | If Below This: |
|---|---|---|
| Average women | 1,200โ1,400 kcal/day | Increase activity; do not cut calories further |
| Average men | 1,500โ1,600 kcal/day | Increase activity; do not cut calories further |
| Very small women (<55 kg) | 1,100โ1,200 kcal/day | Smaller deficit (200โ300 kcal); prioritise protein |
| Athletes (any gender) | BMR ร 1.2 | Reduce deficit size; never go below BMR |
Ready to calculate your personal TDEE and set your deficit target?
Use our www.calculator-tdee.com to find your personal number โ your maintenance calories, your 500-calorie deficit target, and full macro breakdowns are all included in the results.
Calculate My TDEE & Deficit โ