Reformulate a planned meal without losing the macros

The plan is working, but one meal is too hard to get down. Breakfast has too much volume, lunch repeats the same protein, or dinner needs a smaller oil pour — you want the food changed while the day still lands on the same targets.

What the agent needs to hear

Behind your sentence, the agent works backwards to four pieces: which day, which meal, what can change, and which targets must stay fixed. Active plan and today’s date are implicit when you say « breakfast » or « lunch today ». If you mean a template day instead of today, name it: « training day breakfast » or « rest day dinner ».

The important part is telling the agent what is flexible. « Make breakfast easier » lets it reduce high-volume foods and rebalance with denser ones. « Keep the tortilla and berries fixed » locks those rows. « Swap chicken for prawns » gives the food direction but still lets portions move.

Targets are usually daily macros, not item-by-item macros. Say « keep the day the same » when calories, protein, carbs and fat should stay aligned. Say « just keep protein » when carbs and fats may drift.

Portions, locks, and swaps

Portions are the first lever. The agent can lower a quantity, raise another, remove a small item, or add a new item if the meal needs somewhere for the macro delta to go. A simple quantity change should stay on the same row, which means alternatives already configured on that row stay intact.

Swaps are the second lever. « Chicken to prawns » or « oats to rice porridge » changes the reference and recalculates the portion. If the replacement has a different macro shape, the agent adjusts another flexible item instead of pretending the foods are equivalent.

Locks matter because they protect habit. « Do not touch the coffee or fruit » keeps those rows stable. « Keep dinner unchanged » tells the agent to rebalance inside breakfast and lunch only. The fewer locks you give, the easier it is to hit the day cleanly.

What the preview protects

The preview is the contract before anything changes. It shows the current day, the projected day, and the macro delta between them. It also separates calorie, protein, carb, and fat status so the agent can tell whether the day is truly on target or only one macro is still off. That is where you catch whether « easier breakfast » accidentally became a different diet.

Without a preview, meal reformulation is easy to do halfway: one item removed, another added, alternatives lost, totals checked after the damage. The safe flow is converge first, save second. When several rows move at once, the final save lands as one edit, so the meal does not sit in an in-between state if a reference fails.

That matters downstream because adherence reads the plan, not the intention. If the planned totals stay honest, weekly nutrition review remains useful. If a reformulated meal quietly drifts 25 g of carbs, the plan starts grading you against a target you no longer meant.

When the agent gets it wrong

Three corrections come up most often. The agent chose the wrong row — « not the tortilla, the egg whites » points it back to the item that should move. It over-flexed a locked habit — « keep the berries exactly as they are » freezes that row and reruns the preview.

The third is a macro priority mismatch. Maybe the agent held calories but let protein fall, or preserved protein and pushed fats too high. Correct it in the same language: « protein cannot move » or « keep fats under 55 g ». The preview rerenders; no save happens until the new shape reads right.

If the food match is wrong, name the catalog entry more plainly. « I mean cooked prawns, not raw » or « use the custom turkey breast I saved » is enough. The agent should resolve the reference, recalculate, and show the new delta before asking again.

What makes the reformulation worth keeping

Three things decide whether the reformulation helps you later: the target day is the one you actually follow, the locked items match the habits you do not want disturbed, and the macro delta is small enough that adherence still means what it says. The system uses the saved plan for logging, suggestions, shopping lists and weekly review; a sloppy reformulation turns all of those into noisy mirrors. A good one makes the plan easier to live with without changing what it is trying to do.