Meal prep scaling calculator

The Mathematics of Scaling Weekly Batch Cooking

The most frequent mistake newcomers make when meal prepping is failing to account for cooking shrink loss. Weighing cooked meat against raw meat grocery targets results in running short on portion sizes by the fourth or fifth day of the week.

Accurately scaling ingredients from target container macros to supermarket shopping carts requires understanding moisture loss physics and raw-to-cooked conversion factors.

The Meat Shrinkage Factor

When animal proteins (chicken breast, ground beef, steak, turkey) are baked, pan-seared, or grilled, muscle fibers denature and release moisture. On average:

• Boneless Skinless Chicken Breast: Loses 25% to 30% of its raw weight during cooking (a shrinkage factor of 1.33x to 1.40x).
• 90/10 Ground Beef: Loses 28% to 35% through water evaporation and rendered fat (a shrinkage factor of 1.38x).
• Atlantic Salmon: Loses 20% to 25% of raw weight.
• Extra Firm Tofu (Pressed): Loses 10% to 15% of weight when air-fried or pan-crisped.

The Golden Rule: To yield 30 ounces of cooked chicken breast across 5 containers (6 oz cooked per box), you must purchase at least 40 ounces (2.5 lbs) of raw chicken at the grocery store ($30 \times 1.33 = 40$).

Carbohydrate Water Absorption Ratios

Unlike meats, dry carbohydrate grains absorb water during cooking and expand:

• White & Jasmine Rice: Multiplies in cooked weight by approximately 2.8x to 3.0x (1 dry cup / 185g dry rice yields ~520g cooked rice).
• Rolled Oats: Multiplies by 2.5x to 3.0x when cooked in water or milk.
• Dry Pasta: Multiplies by 2.2x to 2.4x when boiled al dente.
• Sweet Potatoes & Baking Potatoes: Suffer modest moisture evaporation (~10% weight loss) when baked or roasted.

Container Assembly Workflow

1. Cook proteins and carbohydrates in separate sheet pans or large pots.
2. Place a meal container on a digital kitchen food scale and tare to zero.
3. Spoon the target cooked protein weight first (e.g., 6.0 oz / 170g).
4. Tare the scale again and spoon the target carb weight (e.g., 150g cooked rice).
5. Add raw or steamed greens (broccoli, green beans, asparagus), which add minimal calories but high fiber and micronutrients.