Cut First or Bulk First?
Same Finish Line.

Almost everyone who starts lifting asks this and gets a confident answer either way. Cut first, because you partition nutrients better when lean. Bulk first, because you'll lose muscle cutting with nothing to show. Both answers come with a mechanism, and both mechanisms fall apart when you look.

The partitioning story is dead

The claim is that fatter people send more of a surplus to fat and less to muscle, so get lean before you build. An individual-participant re-analysis of seven lifting studies, with starting body fat from under 5% to over 50%, found starting fat had no effect on fat-free-mass gain at all.^[1] A 2025 overfeeding study found the same null on muscle: starting fatter meant gaining more fat per unit of surplus, but not less muscle.^[2]

So there's half a reason to lose fat before a surplus, which is that the surplus deposits a bit more fat when you start fatter. There's no reason on the muscle side. And the insulin-sensitivity mechanism everyone cites has been tested directly and doesn't hold up.

Why the order barely matters: the arithmetic

Here's what's actually fixed. How fast you can build muscle is capped by your training age, and more food can't raise it.^[3] How much fat you have to remove is your starting excess plus whatever the build adds. Those two totals are the same whichever order you do them in. Run the numbers on a 90 kg lifter at 25% body fat heading for 90 kg at 14%, and cut-first takes about 31 months while build-first takes about 30 and a half. Half a month, on a two-and-a-half-year plan.

The order is a preference. It changes what the scale reads on the way, not where you end up or when.

What the order does change

Lived experience. Build first keeps that 25% lifter at around 24% for two years before one short cut. Cut first has him lean in five months, then building from there. Same muscle, same finish, very different year. The right question isn't which is optimal. It's whether you'd rather be lean and smaller now, or bigger and softer now.

It also changes how often you cut. Chunking the fat loss into a few short cuts between builds costs no extra time, and the one trial of interrupted versus continuous dieting in trained lifters found no difference in fat, muscle or strength, only less hunger and more satisfaction in the interrupted group.^[5]

The one real rule: stay in the healthy range

Preference has a boundary. Cutting very lean is where the costs stop being arithmetic. In a documented natural-bodybuilder prep from 15% to under 5%, testosterone fell to a quarter and strength hadn't fully recovered six months later.^[4] You don't need to go anywhere near that, and the fat-energy ceiling makes it hard to try: the leaner you get, the less deficit your fat can supply. So the band to move in is roughly 12 to 18% body fat for men and 22 to 27% for women. Cut to the bottom of your band, build toward the top, and pick the order that suits you.

What the app does

Coast asks where you want to sit, then shows the route either way: how low you'll go, how high, how many cuts, and when. It doesn't claim one order is better, because the evidence says it isn't, and it never sends you under the floor. The whole route is visible, running live on my own scans, in The Lab.