Fatigue, flat lifts and a stuck scale are the shared symptoms of at least five different problems, and the fixes point in opposite directions. One needs more food, another needs less training, another needs a blood test. This works out which one is actually limiting you, and tells you what you are about to do that would make it worse.
Measurement is checked first, because nothing else can be diagnosed without real data behind it, and expectation is checked second, because the rate you are seeing may simply be normal for your training age. Only once both pass does the tool rank the remaining domains against each other, which stops an advanced lifter's ordinary slow year from being misread as a stimulus, fuel or recovery problem it never was.
Each diagnosis is paired with what you were probably about to do next and whether it actually helps. Adding volume and cutting calories is the default response to a plateau, and for under-fuelling and under-recovery specifically, that response deepens the exact problem causing the stall rather than fixing it. Cross-check your intake numbers against the Calorie & Macro Calculator if fuel comes back as your limiter.
When the physiology domain scores as the limiter, the tool routes to specific markers, ferritin, vitamin D, a full thyroid panel with free T3, and testosterone, rather than suggesting a supplement stack. It also runs a separate sleep apnea screen from snoring, daytime sleepiness and neck circumference, since that specific condition is invisible to any training or diet change. Confirm anything flagged against the Bloodwork Analyzer.
Because a plateau you cannot see cannot be diagnosed. If you are not weighing consistently, tracking intake or logging lifts, the tool routes there first regardless of what else is going on, since nothing downstream can be assessed reliably without real data.
If the rate of progress you are describing is actually normal for your training age, that is the answer rather than a problem to fix. A lifter five years in gaining a couple of kilos of muscle a year is not stalled, that is what year five looks like, and no programme change or compound restores year-one gain rates.
Because the instinctive response to a plateau is almost always to add volume and cut calories, and for three of the six bottlenecks that makes the actual problem worse rather than better. Under-fuelling met with a harder cut deepens the deficit causing the stall. Under-recovery met with more volume removes the one thing that could fix it. Naming the wrong instinct before it happens is the point.
Yes, as a separate screen alongside the six main domains. Snoring, daytime sleepiness, waking unrefreshed and a larger neck circumference are standard screening signals, and untreated apnea suppresses testosterone and blunts recovery while producing exactly the flat, fatigued, nothing-is-working picture the tool is built to differentiate. It is invisible to any training or diet change, which is why it gets called out on its own.
The tool runs a specific safety check: low calorie intake per kg combined with low body fat and symptoms like constant cold, disappeared hunger or lost libido triggers a message that this is not a plateau to push through, since the body has likely already started deprioritising non-essential functions. The answer there is more food and, where it has been going on a while, a conversation with a doctor or dietitian rather than another training change.
