Nutritional Science

Your Blueprint is built on
peer-reviewed science.

Every calorie target, macro split, and time-to-goal projection MacroMealBlueprint generates is derived from established, published formulas — not guesswork. Here's exactly what runs under the hood and where each formula comes from.

Logical reading order

Step 1 BMI Healthy target weight

Step 2 BMR Resting calorie burn

Step 3 TDEE Total daily calories

Step 4 Macro Split Grams per macro

Step 5 Gap Fill Remaining grams today

Step 6 Time to Goal Weeks to target weight

01 — Body Mass Index

BMI & Healthy Weight Range

BMI anchors the Blueprint to a clinically defined healthy weight range. Rather than asking users to self-set a goal weight, MacroMealBlueprint uses the NIH BMI 18.5–24.9 range to calculate what a healthy target weight looks like for a given height — keeping goals medically grounded.

Metric:   BMI = W / H²         (W in kg, H in meters)
Imperial: BMI = (W × 703) / H²  (W in lbs, H in inches)

Healthy range from height:
Min Healthy Weight (kg) = 18.5 × H²
Max Healthy Weight (kg) = 24.9 × H²

BMI	Category
< 18.5	Underweight
18.5 – 24.9	Healthy Weight
25.0 – 29.9	Overweight
≥ 30.0	Obese

Worked Example — 165 cm / 68 kg

H = 1.65 m  →  H² = 2.7225

BMI check:  68 / 2.7225 = 24.98  →  Healthy ✓

Healthy range:
  Min: 18.5 × 2.7225 = 50.4 kg  (111 lbs)
  Max: 24.9 × 2.7225 = 67.8 kg  (150 lbs)

NIH National Heart, Lung, and Blood Institute. Calculate Your Body Mass Index. nhlbi.nih.gov

02 — Basal Metabolic Rate

Mifflin-St Jeor Equation

BMR is the number of calories the body burns at complete rest — the floor of energy expenditure. MacroMealBlueprint uses the Mifflin-St Jeor equation, which a 2005 meta-analysis in the Journal of the American Dietetic Association found to be the most accurate BMR predictor for healthy adults, outperforming the older Harris-Benedict equation.

Men:    BMR = (10 × W) + (6.25 × H) − (5 × A) + 5
Women:  BMR = (10 × W) + (6.25 × H) − (5 × A) − 161

Variable	Description
W	Weight in kilograms (kg)
H	Height in centimeters (cm)
A	Age in years

Worked Example — 35F, 68 kg, 165 cm

BMR = (10 × 68) + (6.25 × 165) − (5 × 35) − 161
    = 680 + 1,031.25 − 175 − 161

= 1,375 kcal/day

Mifflin MD, St Jeor ST, et al. (1990). A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 51(2):241–247.

03 — Total Daily Energy Expenditure

TDEE & Activity Multipliers

TDEE scales BMR by how active a person is. This gives the calorie level required to maintain current weight — the baseline from which all targets and deficits are calculated. MacroMealBlueprint also uses activity level change (e.g., going from sedentary to moderately active) to calculate a new TDEE, so the Blueprint accounts for planned lifestyle changes, not just current ones.

TDEE = BMR × Activity Multiplier

Calorie Adjustment for Goals:
Weight Loss    → TDEE − 500 kcal/day  (~1 lb/week)
Maintenance    → TDEE
Weight Gain    → TDEE + 300–500 kcal/day

Activity Level	Description	Multiplier
Sedentary	Desk job, little or no exercise	× 1.200
Lightly Active	Light exercise 1–3 days/week	× 1.375
Moderately Active	Moderate exercise 3–5 days/week	× 1.550
Very Active	Hard exercise 6–7 days/week	× 1.725
Extra Active	Hard daily exercise + physical job	× 1.900

Worked Example — continuing from BMR above

Goal: moderately active, 500 kcal/day deficit

TDEE        = 1,375 × 1.550 = 2,131 kcal/day

Loss Target = 2,131 − 500 = 1,631 kcal/day

McArdle WD, Katch FI, Katch VL. Exercise Physiology. Lippincott Williams & Wilkins. · Frankenfield D, et al. (2005). J Am Diet Assoc. 105(5):775–789.

04 — Macro-to-Calorie Conversion

Atwater General Factors

Once a calorie target is set, it needs to be translated into grams of protein, carbohydrates, and fat. This uses the Atwater general factors — the same standard used by the FDA and USDA for all nutrition labeling in the United States, established in 1896 and unchanged since.

Total Calories = (Protein × 4) + (Carbohydrates × 4) + (Fat × 9)

Macro	Calories per Gram
Protein	4 kcal/g
Carbohydrates	4 kcal/g
Fat	9 kcal/g

Worked Example — Blueprint Card (1,850 kcal target)

Protein:      140g × 4 =   560 kcal
Carbohydrates: 180g × 4 =  720 kcal
Fat:            65g × 9 =  585 kcal

Total: 1,865 kcal (~1,850 kcal after rounding) ✓

Atwater WO, Woods CD. (1896). The chemical composition of American food materials. USDA Bulletin No. 28.

05 — Meal Gap Fill

Missing Macro Grams Formula

This is the engine that makes the weekly planner work. Given a daily calorie and macro target plus whatever meals are already planned, it calculates exactly how many grams of protein, carbs, and fat the remaining meals need to supply — which is what drives the recipe suggestions that fill out the week.

Missing Protein (g)  = (T × P% − p × 4) / 4
Missing Carbs   (g)  = (T × C% − c × 4) / 4
Missing Fat     (g)  = (T × F% − f × 9) / 9

Variable	Description
T	Target daily calories (kcal)
P%, C%, F%	Macro split as decimals — must sum to 1.0
p, c, f	Already-logged grams of protein, carbs, fat

A negative result means that macro has already exceeded its daily target.

Worked Example

Target: 1,850 kcal · Split: 30% P / 40% C / 30% F · Already logged: 60g P, 80g C, 20g F

Missing Protein = (1850 × 0.30 − 60 × 4) / 4 = (555 − 240) / 4 =  78.75g
Missing Carbs   = (1850 × 0.40 − 80 × 4) / 4 = (740 − 320) / 4 = 105.00g
Missing Fat     = (1850 × 0.30 − 20 × 9) / 9 = (555 − 180) / 9 =  41.67g

Verification: (60+78.75)×4 + (80+105)×4 + (20+41.67)×9 = 555 + 740 + 555 = 1,850 kcal ✓

06 — Time to Goal

Full Blueprint Projection

This chains every formula above into a single projection: given a person's current situation and goal, how long will a specific calorie plan take to get them there? The 3,500 kcal-per-pound rule — the basis for the time calculation — was established by Max Wishnofsky in 1958 and remains the standard clinical approximation for body fat energy density.

Days to Goal  = (X lbs × 3,500) / Daily Deficit (kcal)
Weeks to Goal = Days / 7

Daily Deficit	Rate of Loss
250 kcal	~0.5 lb/week
500 kcal	~1.0 lb/week
750 kcal	~1.5 lb/week
1,000 kcal	~2.0 lb/week (typical max)

Complete Walkthrough

The full chain, step by step.

Every number your Blueprint shows can be traced back through these six steps. Here's one complete run-through from profile to projected goal date.

Profile 35F, 68 kg, 165 cm

Goal Lose 20 lbs

Activity Change Sedentary → Moderately Active

Current Trend Weight stable (maintaining)

Deficit 500 kcal/day

BMR — Mifflin-St Jeor

BMR = (10 × 68) + (6.25 × 165) − (5 × 35) − 161
    = 680 + 1,031.25 − 175 − 161

= 1,375 kcal/day

Current Intake — inferred from weight trend

TDEE_current = 1,375 × 1.200 (sedentary) = 1,650 kcal
Trend = maintaining → Intake_current = 1,650 kcal

New TDEE — at target activity level

TDEE_new = 1,375 × 1.550 (moderately active)

= 2,131 kcal/day

New Calorie Target — with 500 kcal deficit

New_Calories = 2,131 − 500

= 1,631 kcal/day

Macro Breakdown — 35 / 35 / 30 split

Protein = (1,631 × 0.35) / 4 = 142.7g
Carbs   = (1,631 × 0.35) / 4 = 142.7g
Fat     = (1,631 × 0.30) / 9 =  54.4g

Verification: 142.7×4 + 142.7×4 + 54.4×9 = 570.8 + 570.8 + 489.6 = 1,631.2 kcal ✓

Time to Goal — Wishnofsky 3,500 kcal/lb rule

Days  = (20 lbs × 3,500) / 500 = 140 days
Weeks = 140 / 7

= 20 weeks to reach goal weight

Full Verification 142.7×4 + 142.7×4 + 54.4×9 = 1,631 kcal · 20 weeks · 500 kcal/day deficit ✓

Academic References

Citations

1 Atwater WO, Woods CD. (1896). The chemical composition of American food materials. USDA Bulletin No. 28. Macro-to-Calorie
2 Wishnofsky M. (1958). Caloric equivalents of gained or lost weight. Am J Clin Nutr. 6(5):542–546. Time to Goal
3 Mifflin MD, St Jeor ST, et al. (1990). A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 51(2):241–247. BMR
4 McArdle WD, Katch FI, Katch VL. Exercise Physiology: Energy, Nutrition, and Human Performance. Lippincott Williams & Wilkins. TDEE
5 Frankenfield D, et al. (2005). Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults. J Am Diet Assoc. 105(5):775–789. TDEE validation
6 NIH National Heart, Lung, and Blood Institute. Calculate Your Body Mass Index. nhlbi.nih.gov BMI

Your Blueprint is built onpeer-reviewed science.