Medical sources

Energy expenditure and calorie goal

Where the app uses it: Basal metabolic rate uses the Mifflin-St Jeor equation (weight, height, age and sex). Daily expenditure applies a 1.2 factor to the basal rate and adds the calories of logged exercise. The goal adjustment and the adaptive goal use the approximation of about 7,700 kcal per kg of body weight, whose limits are described by Hall et al.

Sources

1. Mifflin 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. doi.org/10.1093/ajcn/51.2.241
2. Hall KD, Sacks G, Chandramohan D, et al. Quantification of the effect of energy imbalance on bodyweight. Lancet. 2011;378(9793):826-837. doi.org/10.1016/S0140-6736(11)60812-X

Protein, fat and carbohydrate

Where the app uses it: Protein from 1.6 to 2.0 g per kg of body weight depending on the goal, fat from 0.65 to 0.8 g/kg, and carbohydrate filling the rest of the day's calorie goal. The protein range follows the ISSN position stand and the Morton et al. meta-analysis; fat and carbohydrate distribution follows the Dietary Reference Intakes ranges.

Sources

1. Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition Position Stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20. doi.org/10.1186/s12970-017-0177-8
2. Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376-384. doi.org/10.1136/bjsports-2017-097608
3. Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press; 2005. doi.org/10.17226/10490

Sodium, fiber, sugar and saturated fat

Where the app uses it: Generic adult references: sodium up to 2,000 mg per day (WHO), free sugars and saturated fat below 10% of calories (WHO) and fiber at 14 g per 1,000 kcal (Dietary Reference Intakes). The same values feed the diet quality score and the lab test cross-reading.

Sources

1. World Health Organization. Guideline: Sodium intake for adults and children. Geneva: WHO; 2012. www.who.int/publications/i/item/9789241504836
2. World Health Organization. Guideline: Sugars intake for adults and children. Geneva: WHO; 2015. www.who.int/publications/i/item/9789241549028
3. World Health Organization. Healthy diet (fact sheet). www.who.int/news-room/fact-sheets/detail/healthy-diet
4. Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. Washington, DC: The National Academies Press; 2005. doi.org/10.17226/10490

Food composition

Where the app uses it: When a food name matches an item in the database, micronutrients come from USDA FoodData Central. Otherwise they are an AI estimate and are labeled as estimated.

Sources

1. U.S. Department of Agriculture, Agricultural Research Service. FoodData Central (SR Legacy). fdc.nal.usda.gov/

Water goal

Where the app uses it: Goal of 35 ml per kg (men) or 31 ml per kg (women), with small adjustments for height and age. It is a rule of thumb consistent with the total water intake references from EFSA and the Dietary Reference Intakes, not a prescription.

Sources

1. EFSA Panel on Dietetic Products, Nutrition, and Allergies (NDA). Scientific Opinion on Dietary Reference Values for water. EFSA Journal. 2010;8(3):1459. doi.org/10.2903/j.efsa.2010.1459
2. Institute of Medicine. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. Washington, DC: The National Academies Press; 2005. doi.org/10.17226/10925

Sleep

Where the app uses it: The default 8-hour goal (you can change it in your profile) sits within the 7 to 9 hours recommended for adults by the National Sleep Foundation and the 7-hours-or-more consensus from the AASM and the Sleep Research Society.

Sources

1. Hirshkowitz M, Whiton K, Albert SM, et al. National Sleep Foundation's sleep time duration recommendations: methodology and results summary. Sleep Health. 2015;1(1):40-43. doi.org/10.1016/j.sleh.2014.12.010
2. Watson NF, Badr MS, Belenky G, 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. doi.org/10.5665/sleep.4716

Weight and weight commitment

Where the app uses it: The weight trend is a regression over your weigh-ins. In the weight commitment, the maximum loss rate is the lower of 1% of body weight per week and 0.75 kg per week, and the target cannot fall below a BMI of 18.5, the WHO underweight threshold.

Sources

1. Hall KD, Sacks G, Chandramohan D, et al. Quantification of the effect of energy imbalance on bodyweight. Lancet. 2011;378(9793):826-837. doi.org/10.1016/S0140-6736(11)60812-X
2. Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. J Int Soc Sports Nutr. 2014;11:20. doi.org/10.1186/1550-2783-11-20
3. World Health Organization. Obesity and overweight (fact sheet). www.who.int/news-room/fact-sheets/detail/obesity-and-overweight

Exercise calories, VO2max and one-rep max

Where the app uses it: Cardio calories: from average heart rate (Keytel et al.) when provided; otherwise from pace and the METs in the Compendium of Physical Activities. VO2max estimated with the Cooper 12-minute test. One-repetition maximum (1RM) estimated with the Epley formula.

Sources

1. Ainsworth BE, Haskell WL, Herrmann SD, et al. 2011 Compendium of Physical Activities: a second update of codes and MET values. Med Sci Sports Exerc. 2011;43(8):1575-1581. doi.org/10.1249/MSS.0b013e31821ece12
2. Keytel LR, Goedecke JH, Noakes TD, et al. Prediction of energy expenditure from heart rate monitoring during submaximal exercise. J Sports Sci. 2005;23(3):289-297. doi.org/10.1080/02640410470001730089
3. Cooper KH. A means of assessing maximal oxygen intake: correlation between field and treadmill testing. JAMA. 1968;203(3):201-204. doi.org/10.1001/jama.1968.03140030033008
4. Epley B. Poundage chart. In: Boyd Epley Workout. Lincoln, NE: Body Enterprises; 1985. (no online version)

Training load and recovery

Where the app uses it: Training load is minutes × perceived intensity (session-RPE method, Foster et al.) and compares the current week with the average of previous weeks (acute:chronic ratio, Gabbett). The reference of at least 2 strength sessions per week comes from the WHO physical activity guidelines.

Sources

1. Foster C, Florhaug JA, Franklin J, et al. A new approach to monitoring exercise training. J Strength Cond Res. 2001;15(1):109-115. pubmed.ncbi.nlm.nih.gov/11708692/
2. Gabbett TJ. The training-injury prevention paradox: should athletes be training smarter and harder? Br J Sports Med. 2016;50(5):273-280. doi.org/10.1136/bjsports-2015-095788
3. Bull FC, Al-Ansari SS, Biddle S, et al. World Health Organization 2020 guidelines on physical activity and sedentary behaviour. Br J Sports Med. 2020;54(24):1451-1462. doi.org/10.1136/bjsports-2020-102955

Fasting

Where the app uses it: The module logs the window and protocol you choose; the app does not recommend a fasting protocol. For what the literature knows about intermittent fasting, see the review below.

Sources

1. de Cabo R, Mattson MP. Effects of intermittent fasting on health, aging, and disease. N Engl J Med. 2019;381(26):2541-2551. doi.org/10.1056/NEJMra1905136

Blood tests

Where the app uses it: Reference ranges come from your own lab report, not from the app. Minimum retest intervals (lipid panel in weeks, HbA1c in about 3 months) follow the guidelines below. The daily nutrient references used in the cross-reading are those in the sodium, fiber, sugar and saturated fat topic.

Sources

1. Grundy SM, Stone NJ, Bailey AL, et al. 2018 AHA/ACC/AACVPR/AAPA/ABC/ACPM/ADA/AGS/APhA/ASPC/NLA/PCNA Guideline on the Management of Blood Cholesterol. Circulation. 2019;139(25):e1082-e1143. doi.org/10.1161/CIR.0000000000000625
2. American Diabetes Association. Standards of Care in Diabetes (updated annually). professional.diabetes.org/standards-of-care

Glucose sensor (CGM)

Where the app uses it: Time in range of 70 to 180 mg/dL and the other ranges from the International Consensus on Time in Range; GMI per Bergenstal et al. These ranges were defined for people with diabetes: the app uses them to describe the period, not as a goal or diagnosis.

Sources

1. Battelino T, Danne T, Bergenstal RM, et al. Clinical targets for continuous glucose monitoring data interpretation: recommendations from the International Consensus on Time in Range. Diabetes Care. 2019;42(8):1593-1603. doi.org/10.2337/dci19-0028
2. Bergenstal RM, Beck RW, Close KL, et al. Glucose Management Indicator (GMI): a new term for estimating A1C from continuous glucose monitoring. Diabetes Care. 2018;41(11):2275-2280. doi.org/10.2337/dc18-1581

Medications and body composition

Where the app uses it: The medication × body reading uses a reference of 1.6 g of protein per kg to preserve lean mass, flags weight loss above 1% of body weight per week and considers at least 2 strength sessions per week. Lean mass loss alongside weight loss on GLP-1 agonists is reported in the STEP 1 trial. The app never suggests a dose, nor starting or stopping a medication.

Sources

1. Wilding JPH, Batterham RL, Calanna S, et al. Once-weekly semaglutide in adults with overweight or obesity. N Engl J Med. 2021;384(11):989-1002. doi.org/10.1056/NEJMoa2032183
2. Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376-384. doi.org/10.1136/bjsports-2017-097608
3. Bull FC, Al-Ansari SS, Biddle S, et al. World Health Organization 2020 guidelines on physical activity and sedentary behaviour. Br J Sports Med. 2020;54(24):1451-1462. doi.org/10.1136/bjsports-2020-102955
4. Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. J Int Soc Sports Nutr. 2014;11:20. doi.org/10.1186/1550-2783-11-20

Supplements

Where the app uses it: The supplement protocol reading is done by AI from what you log. For reference information on each supplement, see the NIH fact sheets.

Sources

1. National Institutes of Health, Office of Dietary Supplements. Dietary supplement fact sheets. ods.od.nih.gov/

AI answers (Insights, Coach, 360 View and suggestions)

Where the app uses it: AI answers start from your logs and from the numbers calculated by the rules on this page, with the same sources. They describe patterns and do not replace an assessment by a health professional. If an answer states something that is not in your data or on this page, treat it as unverified.

This topic has no source of its own: the other topics on this page apply.