TDEE for Cutting — Plan a Controlled Fat Loss Phase

What TDEE Represents

Your Total Daily Energy Expenditure (TDEE) is the total amount of energy your body uses in a complete 24-hour period. It combines the energy needed to keep your body running at rest (BMR) with the additional energy burned during digestion, movement, exercise, standing, walking, and all other activity. TDEE is the number that, when matched by calorie intake, leads to stable body weight over time. Every calorie-based goal — intentional loss, maintenance, or intentional gain — starts from this anchor number.

The Two-Part Formula

Understanding the 6 Activity Bands

The six activity bands correspond to the widely cited Mifflin-St Jeor scaling levels. Sedentary (1.2) describes a largely seated day with no structured exercise and limited walking. Lightly Active (1.375) adds 1–3 days of light exercise or daily walking and steps over roughly 5,000–7,000. Moderately Active (1.55) corresponds to 3–5 days per week of structured exercise — a common baseline for many regular gym-goers and active commuters. Active (1.725) implies 6–7 days of exercise or a job that keeps you on your feet most of the day. Very Active (1.9) combines daily hard training with a physical role or frequent movement, and Athlete (2.0) reflects elite volume, often two daily sessions.

How the Rate Grid Is Built

From your maintenance TDEE, the eight-card grid applies standard weekly rate adjustments. Each pound per week of weight change is converted to per-day calorie shifts using the 3,500 kcal/lb convention: 0.25 lb/week ≈ ±125 kcal/day, 0.5 lb/week ≈ ±250 kcal/day, 1.0 lb/week ≈ ±500 kcal/day, 1.5 lb/week ≈ ±750 kcal/day, and 2.0 lb/week ≈ −1,000 kcal/day (loss-side only). Gain-side rates are capped at 0.5 lb/week in the default grid because faster gains tend to disproportionately increase fat storage rather than lean tissue for most natural non-elite trainees.

Why Prefill via ?bmr=

The optional URL prefill from the BMR Calculator lets you compare formulas on the BMR page, pick the one that best matches your context (for example, using Katch-McArdle if you know body composition), and then carry that specific BMR value forward to the TDEE page. In prefill mode, gender / age / height / weight inputs still update on-screen BMR for reference, but the core TDEE anchor comes from the URL value you brought in. This gives you flexibility to work with your own BMR estimate, indirect calorimetry reading, or wearable-device estimate of daily burn.

Known Limitations of TDEE Math

Population-level equations miss individual variation. Muscle mass, genetics, thyroid function, hormonal cycles, caffeine and stimulant intake, sleep quality, gut absorption, Rx items, body composition adaptations, and even minor unplanned fidgeting can shift real daily burn by hundreds of calories in either direction. The calculator is a reference starting point, not a measured truth. Validating against 2–3 weeks of actual weight data while tracking intake is the most reliable way to refine the number for your unique body.

What a Cutting Phase Actually Is

A cutting phase is a structured period of sustained calorie deficit designed to reduce body fat while preserving as much lean mass as possible. It is commonly used by strength and physique athletes after a building phase, but the same principles work for anyone who wants to lean down deliberately. The cut starts from TDEE (your maintenance level) and applies a controlled deficit, typically 15 to 25 percent below TDEE. A 20 percent deficit is a common starting point — moderate enough to preserve training quality and lean mass, aggressive enough to produce visible fat loss over 8 to 16 weeks. Faster cuts cost more muscle; slower cuts test adherence.

From TDEE to Cutting Target

The chain from TDEE to cutting target is simple: subtract a percentage-based deficit. A 15 percent deficit is mild and works well for lean individuals or long cuts. A 20 percent deficit is the standard starting point for most adults. A 25 percent deficit is aggressive and works for shorter cuts or higher starting body fat. Going above 25 percent is rarely productive — it accelerates muscle loss, disrupts training, and triggers adaptations that stall progress. A practical floor for most adults is to never eat below 1200 kcal per day for women or 1500 kcal per day for men without qualified supervision.

Protein, Training, and Muscle Retention

During a cut, your body breaks down both fat and lean tissue for energy. To tilt the balance toward fat loss and preserve muscle, prioritize protein intake and resistance training. Push protein to the upper end of the standard range — 2.0 to 2.4 grams per kilogram of body weight per day — spread across 4 to 5 meals with 30 to 40 grams per meal. Maintain or slightly increase training intensity (weight on the bar) while reducing training volume if recovery suffers. Strength training during a cut is the single most important signal for preserving muscle; cardio alone is not enough. Endurance athletes should keep carbohydrate around training sessions and never drop below 3 g/kg/day.

Cycle Length and Refeed Days

Most cutting phases last 8 to 16 weeks. Shorter cuts (8 to 10 weeks) work well for those starting at a lower body fat percentage; longer cuts (12 to 16 weeks) work for those with more fat to lose. Beyond 16 weeks, adherence and hormonal adaptation make further loss harder — most people benefit from a 4 to 8 week maintenance break before starting another cut. Refeed days — 1 to 2 days per week of eating at or slightly above maintenance, with the extra calories coming mostly from carbohydrate — can support training quality, replenish glycogen, and provide psychological relief. Refeeds do not boost metabolism meaningfully, but they can improve adherence for some people.

Practical Tracking Tips

• Weigh yourself 3 mornings per week under consistent conditions and use the weekly average. Aim for 0.25 to 0.75 kg per week of loss depending on starting body fat.
• Track strength in your main lifts. If weights stay stable or climb while weight drops, the cut is preserving muscle. If strength drops sharply, add calories or reduce deficit.
• Measure waist circumference at belly-button level every 2 to 4 weeks. Waist is often the most responsive marker of fat loss progress.
• Re-calculate TDEE every 4 to 6 weeks as body weight drops. As weight drops, TDEE drops too, and the original deficit stops producing the same rate of loss.
• Sleep 7 to 9 hours per night. Chronic sleep disruption alters hunger hormones and undermines adherence to any cut.