WHOOP Macro Calculator

How WHOOP Data Influences Your Macro Needs

Most macro calculators treat every day the same. You plug in your weight and activity level, receive a static number, and follow it whether you ran a marathon or sat on the couch. For WHOOP users, that approach leaves performance on the table.

WHOOP captures two metrics that dramatically change how much — and what — you should eat: strain and recovery. Strain quantifies the cardiovascular load your body absorbed during the day on a logarithmic 0–21 scale. A strain of 10 represents a moderate day; a strain of 18 means your heart was working at near-maximal levels for extended periods. Recovery, expressed as a percentage, reflects how well your autonomic nervous system has bounced back overnight, using heart-rate variability (HRV), resting heart rate, respiratory rate, and sleep performance.

Together, these two numbers paint a picture no bathroom scale or step counter can: how much fuel your body actually burned, and how ready it is to absorb and utilize that fuel. That is exactly the information a precision macro calculation requires.

Why Strain Directly Affects Caloric Needs

WHOOP strain is built on a logarithmic model of cardiovascular effort. Each incremental point above ~12 represents a disproportionately larger energy cost. A user who averages a daily strain of 8 might burn 2,200 calories, while the same user at a strain of 16 could burn 3,100+. Ignoring that difference means either under-fueling (risking muscle loss and impaired recovery) or over-fueling (stalling fat loss).

The macro calculator above accounts for this by adding a strain-based calorie modifier on top of the standard Mifflin-St Jeor TDEE estimate. When you enter your average strain:

• Strain 0–7: No additional adjustment — your activity multiplier already covers light daily movement.
• Strain 8–13: A moderate bump (5-15%) reflecting regular structured training.
• Strain 14–17: A meaningful increase (15-25%) typical of serious athletes and high-volume programs.
• Strain 18–21: A substantial boost (25-30%) reserved for ultra-endurance or two-a-day training blocks.

These adjustments are intentionally conservative. If you connect your WHOOP to Plait, the AI model uses your actual calorie burn data from the WHOOP API — not estimates — so the precision increases even further.

How Recovery Percentage Shapes What You Eat

Recovery is about more than soreness. A low recovery score (red or yellow zone) signals elevated sympathetic nervous-system activity, reduced HRV, and poorer sleep metrics. Nutritionally, this means your body's ability to shuttle carbohydrates into glycogen stores is impaired and systemic inflammation is higher.

The calculator applies a subtle ±5% calorie adjustment based on recovery. This is a starting point; Plait's automated system goes deeper by also modifying meal timing and food selection based on your latest recovery reading each morning. For example, a red-zone morning might trigger an anti-inflammatory breakfast rich in omega-3 fats and leafy greens, while a green-zone morning might feature higher-glycemic carbs to pre-load for a big training day.

The Science Behind the Mifflin-St Jeor Equation

We chose Mifflin-St Jeor because it is the most validated BMR equation for non-obese adults, recommended by the Academy of Nutrition and Dietetics. The formulas are:

• Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
• Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161

BMR represents the calories your body burns at complete rest — breathing, circulating blood, maintaining body temperature. Multiplying by an activity factor yields your Total Daily Energy Expenditure (TDEE). The WHOOP strain modifier then layers on real-world training data, and the goal-specific calorie offset (deficit, surplus, or maintenance) gives you a final calorie target that is split into protein, carbs, and fat grams.

Goal-Specific Macro Splits Explained

Fat Loss (40P / 30C / 30F, −500 cal)

The elevated protein ratio preserves lean mass during the calorie deficit. Research shows that athletes consuming 1.6–2.2 g of protein per kilogram of body weight during a cut retain significantly more muscle than those eating lower amounts. The moderate fat intake supports hormone production (especially testosterone and estrogen), while carbs are kept high enough to fuel training without sacrificing the deficit. A 500-calorie deficit targets roughly one pound of fat loss per week — aggressive enough to see results, conservative enough to sustain.

Lean Muscle Gain (30P / 45C / 25F, +300 cal)

Muscle protein synthesis requires an energy surplus, but a massive one just adds body fat. A 300-calorie surplus is the sweet spot for lean gains. Carbohydrates are elevated to 45% because insulin — driven by carb intake — is the most anabolic hormone available without a prescription. Adequate carbs also replenish glycogen, letting you push harder in each session and accumulate more training volume over time.

Body Recomposition (35P / 35C / 30F, maintenance)

Recomp is the art of losing fat while gaining muscle simultaneously. It works best for intermediate lifters eating at maintenance calories with high protein. The balanced macro split ensures recovery without excess energy that would be stored as fat. WHOOP data is particularly valuable here because daily calorie needs fluctuate — Plait's daily-updating meal plans keep you at true maintenance rather than an estimated average.

Endurance Performance (25P / 50C / 25F, +200 cal)

Endurance athletes live and die by glycogen availability. Half of total calories from carbohydrates ensures topped-off glycogen stores before long sessions and faster replenishment afterward. The slight surplus prevents the chronic energy deficiency (RED-S) that plagues runners, cyclists, and triathletes who under-eat relative to their enormous energy output. If your WHOOP strain regularly exceeds 15, this is likely the profile for you.

General Fitness (30P / 40C / 30F, maintenance)

A well-rounded split for active individuals who aren't chasing a specific physique or performance outcome. It provides enough protein for muscle maintenance, enough carbs for daily activity and moderate exercise, and enough fat for hormonal health. Perfect for WHOOP users who want to eat well without obsessing.

How Plait Automates This Entire Process

This calculator gives you a solid snapshot, but your body's needs change every single day. Yesterday's 18-strain CrossFit session demands very different fuel than today's active-recovery yoga flow. That's where Plait comes in.

When you connect your WHOOP account, Plait pulls your strain, recovery, sleep, and calorie data via the official WHOOP API. Each morning, our AI recalculates your calorie and macro targets using the same principles described above — but with actual data instead of averages. It then generates a complete day of meals (breakfast, lunch, dinner, and snacks) that hit those targets, with recipes, prep instructions, and a grocery list.

Hundreds of WHOOP users have already switched from static meal plans to Plait's dynamic approach. The result? Better recovery scores, more consistent energy, and nutrition that finally keeps pace with their training. If you found this calculator helpful, connecting your WHOOP is the natural next step.

Further Reading

Dive deeper into the relationship between WHOOP data and nutrition with these guides:

• How to Convert WHOOP Calories to Macros: Complete Guide
• Building a Nutrition Plan Around Your WHOOP Data
• WHOOP Recovery Explained: What Your Score Really Means
• The 15-Minute Meal Timing Hack That Improved Recovery
• Why Your Recovery Score Drops After Good Sleep
• WHOOP for Beginners: Getting Started Guide