How to lose body fat
without losing the muscle.
Fat loss requires eating less energy than you use. That part is simple and not very interesting. The part that decides whether you like the result is what you keep while it happens, and whether the deficit is one you can actually live in for three months.
The deficit has to be survivable
A large deficit loses weight faster and gets abandoned faster, and more of what it costs you is muscle. Phasebuilt asks for a pace and sets the deficit accordingly: 250 calories below maintenance for gentle, 375 for steady, 500 for ambitious. Steady is the default for a reason.
Protein protects what you already built
In a deficit the body is looking for energy, and muscle is a candidate. Adequate protein plus resistance training is what tells it to spend fat instead. Phasebuilt sets 1.8 g per kilogram of bodyweight for fat loss, which for an 82 kg person is about 148 g a day.
Lift, do not just do cardio
Cardio increases the energy you burn. Resistance training is what gives your body a reason to hold on to muscle while the deficit runs. Dropping the weights and adding more cardio is the classic way to end ninety days lighter and softer than you hoped. The plan includes both, weighted toward the one that protects your result.
Poor sleep changes the maths
If you report under six hours of sleep or high stress, Phasebuilt reduces the deficit by 100 calories rather than ignoring it. Under recovery on top of an aggressive deficit tends to cost you training quality and lean mass instead of speeding anything up. An honest answer produces a better plan than an optimistic one.
Judge it over weeks, not days
Bodyweight moves daily with water, food volume, salt and sleep. None of that is fat. Look at the trend across two to three weeks alongside how your training is going. If both have stalled, the target needs adjusting, and no calculator can skip that step for you. The full calculation method shows you exactly what to adjust.
What happens at day 90
The plan finishes with a roadmap for the next cycle rather than leaving you at the edge of a cliff. Coming out of a deficit deliberately is what stops the weight returning by accident.
This is general fitness information for healthy adults, not medical advice. Speak to a clinician before starting if you are pregnant or postpartum, managing a medical condition, or returning from injury.
Get a fat loss plan with numbers worked out for your body.
Build my free plan