Solve one meal from what is left in your day

One meal, three numbers, a handful of foods. Give the solver the protein, carbs and fat you have left, and it returns grams for each food that land every macro within 5 g.

This article walks through one lunch from start to finish, with every number on the table.

The setup: what is left

Say you are mid day and the plan for the rest of today leaves this meal 45 g of protein, 60 g of carbs and 15 g of fat. That is the scoreboard. In kcal it is 4 times 45, plus 4 times 60, plus 9 times 15, which is 180 plus 240 plus 135, or 555 kcal.

You do not need to type the kcal. The solver works in grams of protein, carbs and fat and calculates kcal from them afterwards.

The foods for the loadout are four: chicken breast, cooked, jasmine rice, boiled, broccoli, blanched, and olive oil. A protein, a carb, a vegetable and a fat. It is the shape most solved meals take, and it makes a clean first example.

What the foods bring

Every food is a small bundle of macros per 100 g. Using the values in the food list the solver ships with, per 100 g:

• Chicken breast, cooked: 31 g protein, 3.6 g fat, 0 g carbs.
• Jasmine rice, boiled: 2.7 g protein, 0.3 g fat, 28.2 g carbs.
• Broccoli, blanched: 2.4 g protein, 0.4 g fat, 7.2 g carbs.
• Olive oil: 0 g protein, 100 g fat, 0 g carbs.

The reason a meal needs solving is visible here. Chicken is mostly protein, but it carries a little fat. Rice is mostly carbs, but it carries a little protein. Broccoli adds a trace of everything. Add up the pieces by hand and you are doing an equation with three unknowns.

The result

Run through the solver, the meal comes back like this.

• Chicken breast, cooked: 110 g.
• Jasmine rice, boiled: 174.3 g.
• Broccoli, blanched: a standard portion.
• Olive oil: 9.6 g.

Totals: 42.4 g protein, 60 g carbs, 14.7 g fat, 542 kcal.

Set against what was left, protein is 2.6 g under, carbs are on the number and fat is 0.3 g under. All three sit inside the 5 g window, so the banner reads on target.

Check the math by hand

You can verify a solved meal with a pencil. Take protein first. The chicken gives 110 times 0.31, which is 34.1 g. The rice gives 174.3 times 0.027, which is 4.7 g. The broccoli portion gives 3.6 g. Together that is 42.4 g, the figure the totals show.

Carbs come out the same way. Rice gives 174.3 times 0.282, about 49.2 g. The broccoli portion gives 10.8 g. That is 60.0 g with nothing from the chicken or the oil.

Fat is the small one. The chicken gives 3.96 g, the rice 0.5 g, the broccoli 0.6 g and the oil 9.6 g, for 14.7 g in total.

There is a full walkthrough of the kcal side in the article on checking a solved meal against 4, 4 and 9.

Why not just eyeball it

Because each food moves more than one macro. If you nudge the rice up to reach the carb number, the protein rises a little too. If you raise the chicken to close the protein gap, the fat rises with it. A meal with four foods has a number of ways to go slightly wrong, and it takes a few rounds to find a combination that lands all three at once.

The solver does those rounds in one step. You still see the whole thing: the grams, the totals and the gaps. It does not hide a result behind a score.

Where the numbers come from

Food values come from USDA FoodData Central, per 100 g. The service publishes more than one kind of data, from analytically derived Foundation Foods to historic Standard Reference entries, and the data documentation explains each type. Totals are as exact as the entries behind them.

Kcal for the meal come from the three macros with the Atwater general factors, which put protein and carbohydrate at 4 kcal a gram and fat at 9, as set out in the FAO paper on food energy conversion factors.

Try it with your own day

The recipe for a first try is short.

1. Work out what is left for the meal. If you have a day target, subtract what you have eaten. The article on macros left versus daily targets shows how.
2. Load a protein, a carb, a vegetable and something for fat. Four foods is plenty.
3. Read the grams. Note which macro has the largest gap.
4. If the display says no exact fit, read the reason line. The article on why a meal cannot close exactly explains the usual causes.

What to expect on the plate

The grams are what you weigh. A food scale and a bowl are enough. Put the bowl on the scale, zero it, add the rice until it reads 174 g, zero again and add the chicken. The household hint beside each row is a rounded helper, not the figure to hit. The article on grams first, cups and pieces second explains the rounding.

Weigh raw unless the row says cooked. Rice that is already boiled is a different food from rice in the packet, and the numbers above are for boiled rice.

The point of the exercise

A solved meal turns a vague target into a short list of weights. Forty five grams of protein left stops being a worry and becomes 110 g of chicken. That is the entire product idea: the post workout meal, the last meal of the day or a lunch in the office, solved to the gram, free, with the working shown.

If you want that for every meal of the day around what you have already logged, the OnMacros hub is where that lives.