Our Sources & Scientific Approach

Energy (Calorie) Estimation

Yuna estimates your daily energy needs using clinically validated predictive equations that have been widely adopted in dietetic practice. Our dietitians evaluated multiple models and selected the approach that consistently demonstrates the highest accuracy across diverse populations. The calculation takes into account:

• Biological sex - Resting metabolic rate differs meaningfully between males and females due to differences in lean mass, hormonal profiles, and body composition.
• Age - Metabolic rate naturally declines with age; our models account for this on a continuous, per-year basis rather than broad age brackets.
• Height & weight - Both contribute to your baseline energy expenditure. Changes in weight are reflected in recalculated targets over time.
• Activity level - We apply a tiered activity multiplier - reviewed by our dietitians - that scales from sedentary through highly active to translate your resting rate into total daily energy expenditure.
• Health goal - Whether your objective is weight loss, maintenance, or gain, Yuna applies a clinically appropriate caloric adjustment that our dietitians have vetted for safety and efficacy.

“We chose our predictive model after reviewing the body of literature comparing energy-estimation equations. The model we use has been shown to be the most accurate for the widest range of body types, ages, and ethnicities.” - Razan Nasser, RD

Macronutrient Targets

Once your daily calorie target is established, Yuna distributes those calories across protein, carbohydrates, and fat. The split is not arbitrary - it follows evidence-based distribution ranges published by leading nutrition authorities and refined by our clinical team:

• Protein - Scaled according to body weight, activity intensity, and whether the user's goal favours muscle preservation or growth. Higher-activity users receive proportionally more protein, consistent with sports-nutrition consensus.
• Carbohydrates - Set to fuel daily activity and cognitive function. The proportion adjusts based on exercise volume and individual metabolic considerations.
• Fat - Maintained within a range that supports hormonal health, cell membrane integrity, and fat-soluble vitamin absorption, while respecting cardiovascular guidelines.

These distributions are periodically reviewed by our dietitians against the latest published systematic reviews and meta-analyses to ensure they remain current.

Micronutrient Recommendations

Yuna tracks vitamins, minerals, fiber, and other micronutrients against reference values drawn from national dietary guidelines. Your personal targets are shaped by:

• Age & life stage - Nutrient needs shift substantially from adolescence through older adulthood; our system applies stage-specific reference values.
• Biological sex - Certain nutrients - such as iron and calcium - have meaningfully different requirements for males and females.
• Dietary pattern - Plant-based, restricted, or allergen-free diets can increase the risk of specific deficiencies; Yuna highlights these when relevant.

Upper intake limits are also enforced so that users supplementing their diet are alerted before exceeding safe thresholds, as defined by published tolerable upper intake levels.

Primary Data Sources

• USDA FoodData Central - The gold-standard reference for nutrient composition of whole and prepared foods, maintained by the United States Department of Agriculture.
• Branded & Packaged Foods - Manufacturer-supplied nutrition facts for packaged products, verified through barcode scanning and cross-referencing with label databases.
• International Nutrient Databases - Regional food composition tables - including those from Health Canada, the UK Food Standards Agency, and others - expand coverage for non-US foods.

Intelligent Meal Analysis

When you log a meal - whether by photo, text description, barcode, or search - our system identifies the food, estimates portion sizes, and maps the entry to the most accurate nutritional profile in our database. The models powering this pipeline are trained on datasets that have been curated and labelled under dietitian supervision, ensuring clinical-grade accuracy rather than crowd-sourced guesswork.

Personalised Guidance

Feedback you receive inside Yuna - from daily insights to longer-term trend analysis - is generated using evidence-based nutrition protocols and then reviewed within a framework designed by our dietitians. This includes:

• Pattern recognition - Identifying recurring nutritional gaps or excesses over multiple days, not just a single meal.
• Goal alignment - Ensuring every recommendation connects back to the user's stated health objectives.
• Safety guardrails - Preventing advice that could lead to overly restrictive intake, nutrient imbalances, or contraindicated dietary changes.

Institutional Standards

• Dietary Reference Intakes (DRIs) - National Academies of Sciences, Engineering, and Medicine
• Dietary Guidelines for Americans - U.S. Department of Agriculture & Department of Health and Human Services
• Evidence Analysis Library - Academy of Nutrition and Dietetics
• Global Nutrition Recommendations - World Health Organization
• Position Papers on Sports Nutrition - International Society of Sports Nutrition

Continuous Clinical Review

Our dietitian team subscribes to a structured review cycle:

• Quarterly literature scans - Systematic reviews, meta-analyses, and landmark RCTs in clinical nutrition are evaluated for relevance.
• Guideline updates - When a governing body revises its recommendations, our team assesses the impact and updates Yuna accordingly.
• Internal validation studies - Anonymised, aggregated user data is compared against expected outcomes to confirm that our models perform as intended.