Meal Prep Calculator

What it does

Meal prep — batch-cooking a week of meals on one weekend day — is the most-effective single intervention for diet adherence, consistently outperforming willpower-based approaches in nutrition research. The mechanism is straightforward: removing the decision and execution friction at meal time (deciding what to eat + shopping + cooking) means you actually eat the planned macros instead of caving to whatever's convenient. Studies of weight-loss adherence show that people who meal-prep 3+ days a week stick to their nutrition plans at 2-3× the rate of those who decide meal-by-meal.

The calculator takes your weekly macro targets (calories, protein, carbs, fat), number of meals to prep (5 days × 1 meal, or 5 days × 2 meals, etc.), preferred protein/carb/veg sources, and outputs a scaled shopping list with quantities, total cost estimate, and prep time estimate. It calculates per-meal portion sizes from your targets, so you don't have to do the math by hand. For a typical 2,000-calorie plan with 30% protein / 40% carbs / 30% fat, a 5-day meal prep needs about 750g chicken or salmon, 1.5kg rice or potatoes, 1.2kg vegetables, and 200g fats (oil, avocado, nuts) — bought in bulk, around $35-50/week.

Practical meal-prep wisdom from food bloggers and registered dietitians: cook once, eat 5x — choose proteins that hold well in refrigeration (chicken thighs, grilled salmon, ground beef, baked tofu — avoid delicate fish like cod that turns mushy after day 2). Cook carbs separately (rice, quinoa, sweet potato hold for 4-5 days in fridge). Pack vegetables under-cooked slightly (al dente broccoli reheats better than fully-cooked, which goes mushy). Keep dressings/sauces separate until day-of so components don’t get soggy. Use glass containers (microwave-safe, no plastic chemical leaching, see contents easily). Most-asked question: yes, prepped meals stay safe in the fridge for 4-5 days if cooked thoroughly and refrigerated within 2 hours.

How to use it

1. Enter your daily calorie and macro targets (protein/carbs/fat in grams).
2. Pick how many days and meals per day you want to prep (5x1 = lunch only; 5x2 = lunch+dinner).
3. Select your preferred protein, carb, and vegetable sources from the menu.
4. Read the scaled shopping list with quantities.
5. Use the prep schedule (typical: 2 hours of cooking on Sunday for a full work week).

When to use this tool

• Starting a new diet or fitness goal where adherence is critical.
• Working a busy schedule where decision fatigue at lunch leads to bad eating choices.
• Saving money — meal prep cuts food costs 30-50% vs eating out for lunch every day.
• Tracking macros precisely (bodybuilding, weight loss, sports nutrition).
• Family meal planning where you’re cooking once and feeding multiple people the same plan.

When not to use it

• Variable schedule eaters who genuinely don’t know what they’ll feel like — meal prep wastes if 30%+ goes uneaten.
• Strict freshness eaters (sushi-grade fish, leafy salad, fresh-baked bread) — those don’t hold for 5 days.
• Eating out 4+ days/week for work or social reasons — different meal-planning approach needed.
• Multi-pathology dietary needs (severe allergies, kidney disease, IBS-FODMAP) — work with a registered dietitian for personalized planning.

Common use cases

• Pre-decision sanity-check on inputs and outputs
• Educational use — demonstrating the underlying concept
• Onboarding a colleague who needs the same calculation/conversion
• Verifying a number or output before passing it on