Planner · free tool

Every pound has to come from somewhere. You get to choose where.

Scale weight is the least interesting number in a cut. This model tracks fat and lean tissue as separate compartments, computes maintenance from lean mass and actual training load, charges each session against a recovery budget that shrinks as the deficit deepens, and partitions every week's loss accordingly. Set a target date and it will tell you what the timeline costs you.

Subject

Start weight (lb)

Body fat %

Goal weight (lb)

Sex (fat floor)

Daily life outside the gym

Fat mass—

Lean body mass—

To lose—

Timeline

Start date

Target date

Horizon—

Required average rate—

Training

Lifts / week

Minutes / lift

How hard you actually train

Training experience

Cardio, stack as many as you do

LISS block

Sessions / wk

Minutes each

HIIT block

Sessions / wk

Minutes each

Extra block

Sessions / wk

Minutes each

Lifting burn—

Cardio burn—

Offset elsewhere—

Net added burn—

Recovery budget—

freshat capacityoverreached

Nutrition

Calories1800kcal

1,000—3,600

Protein150g

00.61.62.33.5 g/kg

——

Carbohydrate150g

Protein—

Carbohydrate—

Fat (remainder)—

Thermic effect—

Periodization

Diet break every

Break length (wk)

Final phase (wk)

Keep this much deficit

Breaks run at maintenance and let adaptive thermogenesis unwind. A final phase eases the deficit so the last few pounds come off cleaner and glycogen refills.

Model

Exercise compensationAdded training is partly offset by drops elsewhere. Off = every burned calorie counts fully. Deficit severity penaltyExtra lean loss past a 25% deficit, blunted by protein.

Max adaptation %

Meals / day

Where the weight comes from

—

—pounds off the scale

—

Fat—

Lean—

—

Trajectory

—

Total weight Body fat % Quadratic fit Fat removed Lean removed

a · curvature

—

b · initial slope

—

c · intercept

—

R² · fit

—

Diminishing returns

—

Week by week

Wk	Date	Phase	Weight	Lean	Fat	BF %	TDEE	Intake	Deficit	Rate	Lean %

Meal plan

—

Validation against published trials

run at each study's own protocol

Trial	Protocol	Outcome	Paper	This model	Verdict

How to read this. Continuous restriction reproduces almost exactly. Direction is right everywhere. Two known gaps: the model understates short-trial lean loss, because two-week DXA changes are mostly glycogen and bound water rather than contractile protein, and it understates the diet-break benefit in MATADOR, where the observed effect is larger than adaptive thermogenesis alone can account for and the mechanism is still debated. Coefficients are not tuned to close those gaps, because fitting one trial at the expense of the underlying physiology makes every other prediction worse.

What this model assumes

Expenditure, built up not multiplied

Maintenance is assembled from parts rather than one activity factor. Resting rate is Katch-McArdle on lean mass. Non-exercise activity comes from your daily-life setting and scales with body weight, so carrying less costs less. Thermic effect is per macronutrient. Training is computed from actual sessions using MET values and body weight, with an EPOC bump that is larger for intervals than steady state.

Exercise does not fully add

Under the constrained-expenditure model, adding training is partly offset by reductions elsewhere: less spontaneous movement, lower resting rate. Compensation here starts near 25% and climbs past 40% at high volumes, and gets worse in a deep deficit. Marginal burn per added session falls steeply, which is why doubling cardio does not double results.

Adaptation is a state, not a formula

Metabolic adaptation accumulates during deficit weeks and partially unwinds during maintenance weeks. That is what makes diet breaks do anything: they buy back maintenance calories. It also means adaptation depends on the path you took, not just the weight you are at.

Recovery is a budget you can overdraw

Each week's training produces a demand, weighted by intensity: a calorie of intervals costs several times the recovery of a calorie of walking. Against that sits a capacity that shrinks as the deficit deepens and rises slightly with adequate protein. Under capacity, lifting protects lean mass. Over it, the excess adds lean loss. This is where a program becomes counterproductive, and it is why the same routine that works at a 20% deficit wrecks you at 45%.

Lifting beats protein

Resistance training is the dominant retention signal, not protein. Stimulus saturates around four hard sessions; past that you accumulate fatigue with no extra protection. With no lifting at all, even 150 g of protein loses roughly 27% of each pound as lean tissue. With four hard sessions it drops to 9%, which is the Longland and Mettler anchor. Protein without training cannot rescue you, and training without protein cannot either.

Limits

Population coefficients on one person. No sleep, stress, drug, illness or menstrual-cycle terms, and adherence is assumed perfect, which it never is. The final phase changes glycogen and water, which affects how you look but not how much fat you carry. Use it to compare plans, not to predict a number.