Last updated: June 29, 2026
Constance estimates your energy needs and your macronutrient intake (protein, carbohydrates, fat) using established scientific formulas and recommendations. This page lists the source behind each calculation and recommendation shown in the app.
Basal metabolic rate is estimated with the Mifflin-St Jeor equation: 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5 (men) or − 161 (women). It is one of the most accurate predictive equations for the healthy general population.
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. — pubmed.ncbi.nlm.nih.gov/2305711
Maintenance calories equal the basal metabolic rate multiplied by a physical activity level factor, adjusted to the training frequency you report. This approach follows international guidance on energy requirements.
FAO/WHO/UNU. Human energy requirements. Report of a Joint Expert Consultation, Rome, 2001. — fao.org/4/y5686e
EFSA Panel on Dietetic Products, Nutrition and Allergies. Scientific Opinion on Dietary Reference Values for energy. EFSA Journal. 2013;11(1):3005. — efsa.europa.eu
For fat loss, Constance applies a moderate deficit (around 15–20% below maintenance) to support gradual, sustainable loss. For muscle gain, a slight surplus (around 8%) is applied. The "maintenance" goal creates neither a deficit nor a surplus.
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
World Health Organization. Healthy diet (fact sheet). — who.int
If you set your own calorie budget when you signed up, YOUR number is the one shown and the calculation above does not apply. You can go back to Constance's estimate at any time from your account.
Constance targets about 1.8 g of protein per kg of body weight (up to 2.0 g/kg for muscle gain), in line with recommendations for physically active people.
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
Fat makes up about 27% of energy intake, within the recommended 20–35% range. Carbohydrates make up the remaining energy after protein and fat.
EFSA. Dietary Reference Values for nutrients — Summary report. EFSA Supporting publication 2017:e15121 (fat, carbohydrates). — efsa.europa.eu/dietary-reference-values
If you set your own intakes for protein, carbs or fat when you signed up, YOUR grams are the ones shown instead of the calculation above, and they do not move when you complete a workout. Each intake is independent: the ones you left empty are still worked out for you.
The silhouette and body fat references used during onboarding are based on commonly accepted body fat percentage categories.
American Council on Exercise (ACE). Percent Body Fat Norms. — acefitness.org
When cycle mode is on, Constance shows iron tracking during your period with a target of 18 mg a day. That is the recommended intake for a menstruating woman aged 19 to 50, against 8 mg/day for a man or a postmenopausal woman: the gap corresponds to menstrual losses. Note that this benchmark covers 97.5% of women and applies to every day of the month, not only during your period. The iron figure shown is an estimate computed from your meal descriptions: it is in no way a blood test, and it can neither diagnose nor rule out a deficiency. Unusual fatigue should be checked with a doctor.
Institute of Medicine (US) Panel on Micronutrients. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc — chapter 9 "Iron". National Academies Press, 2001. — ncbi.nlm.nih.gov/books/NBK222309
Hallberg L, Rossander-Hultén L. Iron requirements in menstruating women. Am J Clin Nutr. 1991;54(6):1047-1058. — pubmed.ncbi.nlm.nih.gov/1957820
Cycle mode never reduces your program on its own. The largest available synthesis (78 studies) concludes that the effect of menstrual cycle phase on performance, in endurance as in strength, is trivial — the authors express it as an effect size, not a percentage — and they explicitly refuse to draw a general recommendation from it. A lighter week is offered only because you may want to ease off, and it is applied only if you ask for it.
McNulty KL, Elliott-Sale KJ, Dolan E, et al. The Effects of Menstrual Cycle Phase on Exercise Performance in Eumenorrheic Women: A Systematic Review and Meta-Analysis. Sports Med. 2020;50(10):1813-1827. — pubmed.ncbi.nlm.nih.gov/32661839
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