Scientific Sources

Kunaz is not a medical device and does not provide medical advice. All values shown are ESTIMATES based on population averages; consult your physician or dietitian for personal health decisions.

Every health-related calculation in this app is based on published scientific sources. Below you can see which source each calculation uses, tap a source to open the original publication.

Energy and calories

1. Basal metabolic rate (BMR), the basis of your daily calorie needsMifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241-247.https://pubmed.ncbi.nlm.nih.gov/2305711/
2. Lifestyle activity (NEAT) and total daily energy expenditureFAO/WHO/UNU. Human Energy Requirements: Report of a Joint Expert Consultation. Rome, 2004. (Physical activity level, PAL factors)https://www.fao.org/4/y5686e/y5686e00.htm
3. Activity calories, kcal = MET × body weight × durationAinsworth BE et al. 2011 Compendium of Physical Activities: a second update of codes and MET values. Med Sci Sports Exerc. 2011;43(8):1575-1581.https://pubmed.ncbi.nlm.nih.gov/21681120/
4. MET coefficient table for activity typesCompendium of Physical Activities, current online table.https://pacompendium.com

Body composition

1. Body fat percentage estimate (starting value when no measurement is entered)Deurenberg P, Weststrate JA, Seidell JC. Body mass index as a measure of body fatness: age- and sex-specific prediction formulas. Br J Nutr. 1991;65(2):105-114.https://pubmed.ncbi.nlm.nih.gov/2043597/
2. Fat loss estimate, assumes 1 kg of fat ≈ 7,700 kcalWishnofsky M. Caloric equivalents of gained or lost weight. Am J Clin Nutr. 1958;6(5):542-546. (A simplified approximation, used for short-term estimates.)https://pubmed.ncbi.nlm.nih.gov/13594881/

Nutrition references

1. Daily reference values for vitamins, minerals and nutrientsU.S. Food & Drug Administration, Daily Value on the Nutrition and Supplement Facts Labels.https://www.fda.gov/food/nutrition-facts-label/daily-value-nutrition-and-supplement-facts-labels
2. Fiber target (14 g per 1000 kcal), omega-3 / omega-6 adequate intakes and macronutrient referencesInstitute of Medicine (NASEM). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington DC, 2005.https://nap.nationalacademies.org/catalog/10490/
3. Daily upper limit for saturated and trans fat (calculated from your daily calorie target)World Health Organization (WHO). Saturated fatty acid and trans-fatty acid intake for adults and children: WHO guideline. Geneva, 2023. Saturated fat below 10% of total energy, trans fat below 1%.https://www.who.int/publications/i/item/9789240073630
4. Daily upper limit for sugar and added sugar (calculated from your daily calorie target)World Health Organization (WHO). Guideline: Sugars intake for adults and children. Geneva, 2015. Free sugars below 10% of total energy.https://www.who.int/publications/i/item/9789241549028
5. Daily protein target (approximately 1.8-2.0 g/kg)Jäger R et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.https://pubmed.ncbi.nlm.nih.gov/28642676/
6. Daily salt and sodium upper limitWorld Health Organization (WHO), Salt reduction fact sheet (recommends less than 5 g of salt per day).https://www.who.int/news-room/fact-sheets/detail/salt-reduction
7. Daily water targetEuropean Food Safety Authority (EFSA), Dietary Reference Values for water. (Kunaz also uses the common clinical ~35 ml/kg approach as a starting value.)https://multimedia.efsa.europa.eu/drvs/index.htm

Food health score (0-100)

1. The 0-100 health score and color band (green/yellow/red) shown for foods, based on the Nutri-Score 2023 nutrient profiling modelMerz B, Temme E, Alexiou H, et al. Nutri-Score 2023 update. Nat Food. 2024;5:102-110.https://pubmed.ncbi.nlm.nih.gov/38356074/
2. The nutrient profiling model Nutri-Score is built on (the negative/positive points logic)Public Health England / Food Standards Agency. Nutrient Profiling Technical Guidance (the Ofcom model).https://www.gov.uk/government/publications/the-nutrient-profiling-model

Sex differences in the exercise score and programs

1. Why the score differs for women and men: the difference in upper body strength is markedly larger than in the lower body, so bodyweight upper body movements where the load cannot be adjusted (pull-ups, dips, push-ups) carry a different average difficultyMiller AE, MacDougall JD, Tarnopolsky MA, Sale DG. Gender differences in strength and muscle fiber characteristics. Eur J Appl Physiol Occup Physiol. 1993;66(3):254-262.https://pubmed.ncbi.nlm.nih.gov/8477683/
2. Knee ligament injuries being more common in women in movements with jumping and landingArendt E, Dick R. Knee injury patterns among men and women in collegiate basketball and soccer. Am J Sports Med. 1995;23(6):694-701.https://pubmed.ncbi.nlm.nih.gov/8600737/
3. A current review of the same difference (meta-analysis of ACL injury risk)Montalvo AM, Schneider DK, Yut L, Webster KE, et al. "What’s my risk of sustaining an ACL injury while playing sports?" A systematic review with meta-analysis. Br J Sports Med. 2019;53(16):1003-1012.https://pubmed.ncbi.nlm.nih.gov/29514822/
4. Why the program generator expects a different muscle distribution for women and men: the difference in muscle mass between women and men is larger in the upper body than in the lower body, so in women the arms make up a smaller share of total muscle on averageJanssen I, Heymsfield SB, Wang ZM, Ross R. Skeletal muscle mass and distribution in 468 men and women aged 18-88 yr. J Appl Physiol. 2000;89(1):81-88.https://pubmed.ncbi.nlm.nih.gov/10904038/
5. Why rest between sets is slightly shorter for women: at a similar relative intensity women fatigue later on average; because the difference depends on the task, the applied difference is kept smallHunter SK. Sex differences in human fatigability: mechanisms and insight to physiological responses. Acta Physiol (Oxf). 2014;210(4):768-789.https://pubmed.ncbi.nlm.nih.gov/24433272/

Sleep

1. Ideal sleep duration range (7-9 hours)Watson NF et al. Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society. Sleep. 2015;38(6):843-844.https://pubmed.ncbi.nlm.nih.gov/26039963/

Kunaz age guess

1. Activity threshold: at least 150 minutes of moderate intensity per weekWorld Health Organization (WHO), Physical activity fact sheet.https://www.who.int/news-room/fact-sheets/detail/physical-activity
2. Sleep band: 7 to 9 hours for adultsHirshkowitz M et al. National Sleep Foundation sleep time duration recommendations. Sleep Health. 2015. (PMID 26039963)https://pubmed.ncbi.nlm.nih.gov/26039963/

Modeling assumptions (not from literature)

• Our daily muscle protein synthesis estimate is capped at 25 g/day. This is not a threshold taken from a single publication; it is a conservative model ceiling we chose to avoid over-estimation.
• The "ideal" calorie deficit band (approximately 800-1,400 kcal) and the training/sleep multipliers are our own modeling choices, aimed at a safe and sustainable range.
• Fat and muscle values are ESTIMATES unless you enter a measurement. Once you enter your own measurement, the app uses your value instead of the estimate.
• Nutri-Score asks for the percentage of fruit, vegetables and legumes in a food. Our catalog holds nutrient values, not ingredient lists, so that percentage is estimated with a structural rule (plant based, not a drink, low in fat and protein, low in calories and with no added sugar counts as whole fruit or vegetable). We measured it: the only visible effect is on sweet whole fruit such as banana and grapes; other foods score the same either way.
• Nutri-Score uses a stricter table for drinks. We recognize a drink from its unit of measure (ml), so a drink stored in grams (ayran, for example) is scored with the food table, which treats it somewhat generously.
• Nutri-Score gives five grades (A to E). We show three colors instead: A and B are green, C is yellow, D and E are red.
• Three details of the model are not applied because the catalog lacks the information they need: the protein cap for red meat products, giving waters an automatic A, and the extra penalty for drinks with non-nutritive sweeteners. All three point the same way, making the score slightly generous.
• The comment under the score is written by AI and is based only on that food's own nutrient values. It is not medical advice.
• In the age guess, the weights that turn a threshold deviation into years are Kunaz's own model, not literature. The thresholds (sleep band, activity target) are cited; how we convert them into years is our choice.
• No verifiable literature reference band was found for the resting heart rate factor. Its direction and weight are entirely a Kunaz assumption, which is why no recommended range is drawn on its chart.
• The "Kunaz users" line in the charts is not a population statistic. It is the average of Kunaz users, split by age band, sex and activity level, and it is hidden when there are not enough users.
• The age guess looks at your whole history (up to a year), not just the last week. Recent weeks count more: a week's weight halves every 6 weeks. This rate is Kunaz's modeling assumption, not taken from the literature.
• The exercise score (0-100) is Kunaz's own model, not a published scale. It combines the training benefit of the movement (how many muscles work and how hard, metabolic cost, muscle gain factor) with a credit for mobility and flexibility work, then weighs that against safety. The weights and the color thresholds are our choice.
• The injury risk part of the score is not a measured injury statistic. It is derived from the technical difficulty of the movement, how much the lower back is loaded, how explosive it is, and whether the equipment guides the movement path. A low score does not mean the movement is bad, it means it serves a different purpose.
• Women and men are shown separate exercise scores, and a person who has not set their sex is shown the male score. The direction of the difference rests on the sources above, but its size is Kunaz’s own choice: there is no published table saying how many points a given movement should lose. The difference sits only on the safety side, never on the benefit side, so no exercise counts as worth less for a woman. Roughly one in ten exercises in the catalog scores differently; the rest are identical for both. This is not a health assessment and should not be read as a personal injury risk estimate.
• When you create a program, women get a different program from men. In strength and calisthenics programs, rest between sets is 15 percent shorter for women (at least 30 seconds). Bodyweight upper body movements and jumping movements move further down the list for beginner women; at intermediate level this effect is halved, and at advanced level it is not applied. No movement is ever excluded. If a regional muscle measurement exists, a smaller expected share is used for the arms in women. The direction of these differences comes from the sources above, but their size is Kunaz’s own choice. Users who have not set their sex get the male settings. This is not a health assessment.
• The protein, carb and fat colours on the home screen are calculated in grams per kilogram. The weight used is the smaller of your weight and the weight that equals a body mass index of 25 for your height, so extra weight does not earn protein for fat mass. The green ranges are 1.6-2.2 for protein, 2.5-4.0 for carbs and 0.8-1.2 g/kg for fat; in both directions yellow comes first, then red. The protein range comes from the ISSN source above; the other ranges and the yellow/red limits are Kunaz's own choice. Balanced plate points are given based on the end-of-day status. This is not a health assessment.
• The goal picture is an ILLUSTRATION built from the person's own target numbers; it is not a prediction of how they will actually look and it promises no result. The AI model keeps the person in the photo and changes only the body composition, by the amount the numbers imply. The arrival time under the picture is worked out from that person's own pace over recent weeks, not from any external norm or published table. Kunaz does not judge the body on this screen, it only shows the goal the person set. The picture is drawn on purpose at the optimistic end of the goal: muscle tone and definition are shown at the favorable end of what that body fat level allows. This is a motivational choice, not a measurement.