Cutting means running a structured calorie deficit specifically aimed at losing fat while holding onto as much muscle as possible — usually after a period spent building that muscle in the first place. The calorie math behind it is identical to any other weight-loss phase; what actually distinguishes a cut is the priority placed on protein and continued training so the deficit takes fat, not the muscle it took months to build.
This distinction matters practically, not just semantically. Someone cutting after a bulk has something specific to protect that a first-time dieter doesn’t necessarily have front of mind — muscle built deliberately over months of training and surplus eating, which a poorly run deficit can erode almost as easily as it removes fat if protein and training aren’t treated as part of the plan rather than an afterthought to the number on the scale.
Picking a deficit size
This site’s calculators offer three structured deficit sizes: a mild deficit of -250 kcal/day, a standard deficit of -500 kcal/day, and an aggressive deficit of -750 kcal/day. The aggressive option carries an inline caution and isn’t the default, because larger deficits carry a real, meaningful risk of losing muscle alongside fat, and tend to be considerably harder to sustain consistently for weeks at a time than a more moderate one. A slower, moderate deficit sustained consistently generally beats a faster, aggressive one that’s abandoned after a week or two.
Protein is the priority macro during a cut
The same roughly 1.6-2.2g/kg training range that applies during a surplus matters even more during a deficit — staying toward the upper end of that range, rather than the lower end, becomes more important specifically to protect lean mass while total calories are restricted. Protein is also the macro most associated with feeling satisfied on fewer calories, which matters practically as much as the muscle-preservation case does when a deficit is being sustained for months at a time.
Training during a cut
Continuing resistance training — not switching entirely to cardio — is what gives the body a physiological reason to hold onto muscle rather than treat it as available energy alongside body fat during a deficit. Training volume or intensity may need to come down somewhat compared to a surplus phase, since recovery capacity is reduced on fewer calories, but stopping resistance training altogether removes the main signal that’s actually protecting muscle through the deficit.
Why very aggressive deficits backfire
Beyond the muscle-loss risk, very large deficits run into diminishing returns fairly quickly: adherence gets harder as hunger increases, energy for training drops, and the gap between “sustainable for a few weeks” and “sustainable for the months a real cut often takes” widens. The 1,500 kcal (men) / 1,200 kcal (women) safety floor this site enforces on every calculated target exists precisely because pushing a deficit past a reasonable point stops being an effective way to lose fat and starts being a way to lose muscle, energy, and adherence all at once.
A worked example of a deficit shrinking mid-cut
Take a 12-week cut starting with a calculated 500 kcal/day deficit. By the time 6kg is lost — a realistic total over that stretch — the same TDEE math covered in adjusting a calorie target means the real deficit against current TDEE has narrowed well below 500 kcal/day if intake was never updated, purely because a lighter body needs less energy to maintain itself. Someone eating the same fixed number for all 12 weeks is, without realizing it, dieting harder at the start than at the end — which is exactly the pattern behind a cut that seems to stall in its later weeks despite consistent adherence the whole way through.
Diet breaks
For cuts running more than eight to ten weeks, a planned week or two back at maintenance partway through — a “diet break” — is a reasonable way to ease the cumulative adherence fatigue and training-recovery strain a long deficit produces, without abandoning the cut entirely. This isn’t a requirement for a shorter cut, but for a longer one it’s often what actually makes finishing realistic, rather than the deficit being abandoned altogether once motivation runs out somewhere in the middle.
A diet break isn’t the same thing as calorie cycling, even though the two get confused online. A diet break is one longer pause at maintenance partway through a cut; calorie cycling varies intake day to day or week to week while the deficit keeps running the whole time. If what you’re actually looking for is the day-to-day version, that article covers how to build one from your own TDEE.
What to expect on the scale in the first week or two
A new deficit’s early scale movement is usually larger than the calorie math alone would predict, mostly from water tied to reduced glycogen stores dropping alongside the first bit of actual fat loss — not a sign the deficit is working unusually well, and not something that continues at the same rate. This is another reason a weekly average trend, rather than any single early reading, is the more reliable number to plan around once a cut is a few weeks in.
Recalculating during a cut
The same TDEE-falls-as-weight-falls mechanics covered in adjusting a calorie target as you lose weight apply directly here — a deficit sized correctly at the start of a cut narrows in real terms as weight comes off, purely because a lighter body needs less energy to maintain itself. Recalculating every few weeks, using current weight rather than a starting number from months earlier, keeps the deficit at the size it was actually meant to be throughout the whole cut, not just at the beginning.
What a cutting week actually looks like
Execution matters as much as the numbers on paper. A high-protein meal plan already treats protein as a floor rather than a rough target, and batch cooking makes it realistic to hit that floor consistently across a full week rather than only on days with time to cook from scratch — which matters more during a cut, when there’s less calorie margin to absorb an off-plan meal than there was during a surplus.
Common cutting mistakes
A handful of patterns account for most cuts that either stall or cost more muscle than necessary. Jumping straight to the aggressive deficit option on the assumption that faster is simply better skips past the actual tradeoff — a faster cut isn’t a better one if it isn’t sustained long enough to reach the goal, or if it costs meaningfully more muscle along the way. Cutting cardio volume up while cutting calories down, rather than prioritizing keeping resistance training intact, removes the main signal protecting muscle at exactly the point it matters most. And abandoning the deficit the first time the scale doesn’t move for a week — rather than checking the trend over two to three weeks, accounting for the water-weight noise covered above — leads to a lot of restarted cuts that never get far enough in to show real results.
Putting together a cutting plan
A cutting plan that actually preserves muscle isn’t really a different set of rules from any other deficit — it’s the same calorie math, with protein and training treated as non-negotiable rather than optional. A generated meal plan built around a deficit target already applies that protein floor by default, which handles most of the planning side before the deficit itself even needs tracking. The rest is mostly patience: a moderate deficit, protein kept high, training kept intact, and numbers rechecked periodically rather than left to drift — unglamorous, but it’s what actually separates a cut that keeps the muscle from one that just makes the scale go down.