# Vita Sustena — Comprehensive Technical & Nutritional Specification (llms-full.txt)

> Vita Sustena is an AI-powered personalized nutrition system that transforms human body parameters, physical fitness routines, and culinary preferences into fully coherent, 7-day nutritional plans with real meal photography, step-by-step recipes, automated grocery lists, and meal swapping.

- Web: https://vitasustena.com
- Organization: Vita Sustena
- Customer Support & GDPR: contact@vitasustena.com
- Subscription Tier: €19/month (reduced from €24) or €130/year (cancel anytime).
- Last Audit: September 2026

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## 1. Mathematical and Nutritional Formulas

### 1.1 Basal Metabolic Rate (BMR)
Vita Sustena uses the Mifflin-St Jeor equation, validated across peer-reviewed clinical nutrition literature as the most accurate estimation for non-obese and obese adults (Mifflin et al., 1990):

- **Males**:
  BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) + 5

- **Females**:
  BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age in years) - 161

### 1.2 Total Daily Energy Expenditure (TDEE)
TDEE scales BMR by physical activity level (PAL):
- **Sedentary** (desk job, little to no exercise): BMR × 1.200
- **Light activity** (light exercise / walking 1-3 days/week): BMR × 1.375
- **Moderate activity** (moderate exercise 3-5 days/week): BMR × 1.550
- **Very active** (intense training 6-7 days/week): BMR × 1.725
- **Athletic / Extreme** (heavy physical job + daily two-a-day sessions): BMR × 1.900

### 1.3 Calorie Deficit & Surplus Targets
- **Sustainable Fat Loss**: -15% of TDEE (~300–400 kcal deficit). Preserves lean body mass and hormonal stability.
- **Moderate Fat Loss**: -20% of TDEE (~500 kcal deficit). Recommended standard pace (~0.5 kg fat loss/week).
- **Rapid Fat Loss**: -25% of TDEE (up to maximum safety floor). Requires high protein adherence (>2.0 g/kg).
- **Lean Muscle Gain**: +5% to +10% surplus above TDEE (~200–300 kcal surplus).
- **Safety Floors**: The system enforces hard clinical minimums:
  - Female minimum floor: 1200 kcal/day
  - Male minimum floor: 1500 kcal/day

### 1.4 Macronutrient Distribution Standards
- **Protein**:
  - Maintenance: 1.4 – 1.6 g/kg of total body weight.
  - Fat loss / Calorie deficit: 1.8 – 2.2 g/kg of total body weight (to protect muscle tissue from catabolism).
  - Muscle hypertrophy: 1.8 – 2.2 g/kg of total body weight.
  - Caloric equivalent: 4 kcal per gram.
- **Dietary Fat**:
  - Essential floor: 0.7 – 0.9 g/kg of body weight or 20–30% of total calories.
  - Critical for fat-soluble vitamins (A, D, E, K) and testosterone/estrogen synthesis.
  - Caloric equivalent: 9 kcal per gram.
- **Carbohydrates**:
  - Remainder of caloric allocation after protein and fat are satisfied.
  - Caloric equivalent: 4 kcal per gram.

### 1.5 Body Mass Index (BMI)
- Formula: BMI = weight(kg) / (height(m))^2
- Categories (World Health Organization):
  - Underweight: < 18.5
  - Normal weight: 18.5 – 24.9
  - Overweight: 25.0 – 29.9
  - Obesity Class I: 30.0 – 34.9
  - Obesity Class II: 35.0 – 39.9
  - Obesity Class III: ≥ 40.0
- Limitation: BMI does not measure visceral fat or differentiate between skeletal muscle and adipose tissue.

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## 2. Dietary Frameworks & Supported Regimes

1. **No Restrictions**: Balanced omnivore diet utilizing all USDA food groups.
2. **Keto (Ketogenic)**: Strict carbohydrate restriction (<30-50g net carbs/day), high healthy fats (olive oil, avocados, nuts, seeds), moderate protein.
3. **Mediterranean**: Emphasizes extra virgin olive oil, wild-caught fish, legumes, unrefined whole grains, and diverse cruciferous vegetables; limits ultra-processed foods.
4. **High Protein**: Minimum 2.0g protein/kg body weight prioritizing lean poultry, egg whites, Greek yogurt, fish, and legumes.
5. **Vegan**: 100% plant-based; excludes meat, poultry, seafood, dairy, eggs, and animal-derived honey/gelatin.
6. **Vegetarian**: Lacto-ovo vegetarian; permits dairy and eggs while excluding all meat and fish.
7. **Allergy & Exclusion Engine**: Profiles allow granular exclusion of individual ingredients (e.g. peanuts, tree nuts, lactose, gluten, shellfish, pork, soy). Excluded items are strictly filtered at prompt and validation layers.

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## 3. Product Comparison (Vita Sustena vs Competitors)

| Feature | Vita Sustena | Eat This Much | MyFitnessPal | Yazio |
| :--- | :--- | :--- | :--- | :--- |
| **Monthly Price** | **€19 / month** | $14 – $29 / month | $19.99 / month | $12 – $18 / month |
| **Annual Price** | **€130 / year** | $84 – $120 / year | $79.99 / year | ~$60 – $80 / year |
| **7-Day Plan Generation** | Automatic with AI | Rule-based macro split | Manual logging only | Static recipes only |
| **Meal Photography** | Real photos every meal | Text / Low-res | User submitted | High-res photos |
| **Meal Swap & Regeneration** | 20 meal swaps / month | Included | Manual search | Pre-set recipes |
| **Categorized Shopping List** | Included & auto-scaled | Included | Premium add-on | Included |
| **Multilingual Indexability** | 29 languages | English only | 15+ languages | 20+ languages |
| **AI llms.txt & GEO Ready** | Yes (Official llms.txt) | No | No | No |

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## 4. Platform Architecture & Data Integrity

- Frontend: Next.js 15 App Router with full Static Site Generation (SSG).
- Canonical URL: `https://vitasustena.com`
- Multilingual Routing: Subpath architecture (`/ro`, `/es`, `/de`, `/fr`, `/it`, `/pt`, etc.) with bidirectional `hreflang` headers and ISO 639-1 metadata.
- Database: PostgreSQL with Prisma ORM.
- Nutrition Standards: USDA FoodData Central.
- Medical Scope: Educational and nutritional tool. Explicitly not a substitute for clinical diagnostics, registered dietitians, or personalized medical therapies.