Can I change my goal after onboarding?

Yes, and nothing is lost. Goal, rate, protein preference and diet split are all editable, and changing them recalculates your targets from the next day forward without touching a single logged entry. Your trend weight, your training history and your food log are independent of the goal you set against them.

Why does Base ask for my birth year?

Age changes three things it will otherwise refuse to compute: the Mifflin-St Jeor metabolic estimate, the age band used for heart-rate variability and resting heart-rate comparisons, and your estimated maximum heart rate. Without a birth year Base shows no heart-rate zones rather than assuming a default, because a fabricated maximum produces fabricated zones.

What gain rate should I pick?

The options are generated from your goal and your training experience, expressed as a percentage of bodyweight per week so they scale as you do. More advanced lifters get slower options, because the honest ceiling on lean tissue gain falls as you approach your limit. Past roughly 0.5% of bodyweight per week the additional weight is mostly fat regardless of how well everything else is going.

Is the goal weight required?

No. It is optional and it only sets the estimated finish date. Leaving it blank changes nothing else — your calorie target, macros and rate are all derived from your goal direction and rate, not from a destination.

What does the protein preference actually change?

It sets grams per pound of bodyweight, which is subtracted from your calorie target first. Fat then takes roughly 25% of calories and carbohydrate takes whatever remains. That ordering is why your carb number moves when your training volume moves — the extra calories a hard week earns land where fuel belongs.

Set Up Your Profile and Goal in Base

The four sections

The flow is one screen driven by a step index, with a separate progress bar per section. That is deliberate: a single bar creeping from six percent to eleven over two questions reads as a form that will never end.

Section	Questions	What it produces
Basics	Name, sex, birth year, height, weight, health connections, activity, frequency, experience	The metabolic estimate and the rate ceiling
Set New Goal	Direction, rate, goal weight, summary	Your weekly rate target and daily budget
Set New Program	Training type, protein, diet, summary	The macro split
Set Up Cardio	Which days you run or ride, then the history scan	A threshold per discipline

Cardio is last because the scan it runs needs the bodyweight collected in Basics to model bike power, and because it is the only section that does real work rather than asking a question.

What each answer actually changes

Sex, height and birth year

These three feed Mifflin-St Jeor directly:

men:   BMR = 10 × kg + 6.25 × cm − 5 × age + 5
women: BMR = 10 × kg + 6.25 × cm − 5 × age − 161

That is the cold-start estimate of your maintenance, used until there is enough of your own data to measure it properly. It is deliberately not multiplied by an activity factor — walking and workouts are added on top from your health data, so nothing is counted twice.

Birth year does a second job. It sets the age band for heart-rate variability, resting heart rate and body-fat comparisons, and it is the basis for estimated maximum heart rate. Leave it out and Base shows no zones at all rather than assuming a number.

The three facts Base cannot measure, each stating what it is load-bearing for. Editable at any time from Settings, and every change recalculates forward.

Current weight

Today's number becomes your first weigh-in, so the trend line starts now rather than whenever you next remember. This is the only onboarding answer that also writes a data row.

Experience level

This sets how fast Base will let you try to gain, and it is the answer people get wrong most often in the optimistic direction.

The tier is a prior, not a cap. It is the best guess available before anyone has measured you. Once there are four weeks of your own trend weight, waist and strength data, that evidence moves the ceiling — a lifter adding strength quickly with a flat waist is partitioning well and gets a higher allowance than the table gave them.

One limit survives regardless of evidence: past roughly 0.5% of bodyweight per week, additional weight is fat almost independently of how well everything else is going. That is a limit on how fast tissue can be built, not a conservatism setting.

Goal and rate

Rate is expressed as a percentage of bodyweight per week rather than in pounds, so it scales as you do. The options you are shown are generated from your goal plus your experience, which is why an advanced lifter picking "bulk" sees a shorter list than a novice does.

You can check the arithmetic yourself with the lean gain rate calculator.

Protein and diet

Protein is set per pound of bodyweight and comes out of the calorie target first. Fat then takes roughly 25% of calories, and carbohydrate takes the remainder.

target        3,200 kcal
protein       185 g × 4    = 740 kcal
fat           89 g × 9     = 800 kcal   (25% of target)
carbohydrate  remainder    = 1,660 kcal → 415 g

That ordering is the reason your carbohydrate number moves when your training moves. A week with more endurance volume produces a higher calorie target, and the extra lands in the macro that fuels the work rather than being spread evenly across three that do not all need it.

The diet answer changes only the fat percentage. It does not change your protein and it does not change your calories.

Editing an answer later

Every one of these lives in Settings and every one recalculates forward without touching history.

Sex, birth year, height — Settings, You. Saves as you type.
Goal, rate, goal weight — the Progress & Trend screen.
Protein and diet split — recalculated whenever maintenance is recalibrated.
Training split — the Workout tab, or Settings, Training Program.

Changing your goal does not invalidate a single logged day. Your food log, your training history and your trend weight are measurements; the goal is a target you hold them against.

Common mistakes

Picking a rate from ambition rather than experience. The tiers exist because the partition between lean tissue and fat gets worse as the surplus grows. An aggressive rate does not build muscle faster; it builds the same muscle with more fat attached.

Entering height in the wrong unit. The height step shows the total in inches under the field precisely so a wrong answer is visible. Check it says something like 70 rather than 5.

Skipping the health connection to "set it up later". Everything about the calorie target being responsive depends on it, and later usually means never. It takes one tap.

Treating the goal summary as a promise. The estimated end date is a straight-line projection at your target rate. It is arithmetic, not a forecast, and it will move as your real rate does.

Setting a goal weight and then reading it as the plan. Goal weight only sets the finish date estimate. Leaving it blank changes nothing else at all.

Abandoning onboarding halfway and expecting it to be saved. Nothing is written until the final step, deliberately — a half-configured account with targets derived from answers you never gave is worse than starting again. Leave it unfinished and it resumes where you were next launch.

What to do next

Finish the four sections in one sitting; it takes about five minutes. Then open your dashboard and look at the calorie target it produced — it will be labelled as an estimate, which is exactly what it is until you have logged a fortnight.