Scientific sources
The app doesn’t replace medical advice. It adapts its tips to what you declare, without diagnosing anything. AfterStart is not a medical device. Its calculations and tips rely on the references below: each line says what the app does, then the source, with its link.
Energy and weight
Basal metabolic rate (what your body burns at rest) is calculated with the Mifflin-St Jeor equation, from your sex, age, height and weight.
Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO (1990). A new predictive equation for resting energy expenditure in healthy individuals
An ordinary day’s expenditure is that basal rate multiplied by an activity factor, from 1.2 (sedentary) to 1.9 (very active): the physical activity level principle used by the FAO and WHO. Sport is not counted in advance: only sessions you log are added, on the day.
FAO, WHO, UNU (2004). Human energy requirements. Report of a Joint FAO/WHO/UNU Expert Consultation
The weight-loss pace you choose (0.25, 0.5 or 0.75 kg a week) becomes a daily deficit based on about 7,700 kcal per kilo: 275, 550 or 825 kcal a day.
Wishnofsky M (1958). Caloric equivalents of gained or lost weight
These 7,700 kcal per kilo are an average: real loss varies from person to person, and the estimated date is only a rough guide.
Hall KD (2008). What is the required energy deficit per unit weight loss?
The paces offered stay under one kilo a week, the steady loss the NHS recommends (0.5 to 1 kg a week).
NHS (National Health Service, UK) (2026). Overweight and obesity in adults – Treatment
Intermittent fasting is presented honestly: at equal calories it does not speed up weight loss; it mainly helps you stay within your budget.
Liu D, Huang Y, Huang C, et al. (2022). Calorie Restriction with or without Time-Restricted Eating in Weight Loss
When dieting, the body burns less than expected, and part of that drop comes from everyday movement. The alert’s thresholds are chosen by the app: when your steps last week (median) fall at least 25% and 1,500 steps a day below those of the 4 weeks before, with at least 5 measured days out of 7, Stats and «Tell me» say so. Your budget does not change.
Rosenbaum M, Leibel RL (2010). Adaptive thermogenesis in humans
Under calorie restriction, spontaneous activity often drops without you noticing: that is why this note only appears while dieting (budget below your expenditure), never during a race programme, with a declared injury or pregnancy, or when a safety note is due.
Redman LM, Heilbronn LK, Martin CK, et al. (Pennington CALERIE Team) (2009). Metabolic and behavioral compensations in response to caloric restriction: implications for the maintenance of weight loss
Movement outside sport (walking, standing) is worth hundreds of kcal a day and varies a lot from person to person: that is what your steps measure.
Levine JA, Lanningham-Foster LM, McCrady SK, et al. (2005). Interindividual variation in posture allocation: possible role in human obesity
The walking minutes suggested when your steps drop assume about 100 steps a minute, the pace of a moderate walk (3,000 steps in 30 minutes).
Marshall SJ, Levy SS, Tudor-Locke CE, et al. (2009). Translating physical activity recommendations into a pedometer-based step goal: 3000 steps in 30 minutes
Macronutrients
Protein: 1.8 g per kilo (of your target weight if you want to lose weight), never below 1.6 g/kg, within the 1.4 to 2 g/kg range recommended for active people.
Jäger R, Kerksick CM, Campbell BI, et al. (International Society of Sports Nutrition) (2017). International Society of Sports Nutrition Position Stand: protein and exercise
Fat: at least 20% of the day’s calories, the lower end of the EFSA reference range (20 to 35%).
EFSA, Panel on Dietetic Products, Nutrition and Allergies (2010). Scientific Opinion on Dietary Reference Values for fats, including saturated fatty acids, polyunsaturated fatty acids, monounsaturated fatty acids, trans fatty acids, and cholesterol
Carbohydrates: the rest of the budget, never less than 50 g. Fibre: at least 25 g a day, the EFSA adequate intake.
EFSA, Panel on Dietetic Products, Nutrition and Allergies (2010). Scientific Opinion on Dietary Reference Values for carbohydrates and dietary fibre
When the budget is high, the fibre target follows the rule of 14 g per 1,000 kcal.
Institute of Medicine, Food and Nutrition Board (National Academies) (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids
Sugars: at most 10% of calories, and 5% if you have declared type 2 diabetes or PCOS, following the WHO recommendation.
World Health Organization (WHO) (2015). Guideline: sugars intake for adults and children
Salt: at most 5 g a day. Saturated fat: at most 10% of calories if you have declared high cholesterol. These are the WHO limits.
World Health Organization (WHO) (2026). Healthy diet (fact sheet)
Type 2 diabetes or prediabetes declared: a fibre target of 35 g a day and wholegrain starches, as European diabetes specialists recommend.
Diabetes and Nutrition Study Group (DNSG) of the European Association for the Study of Diabetes (EASD) (2023). Evidence-based European recommendations for the dietary management of diabetes
Tell me’s tips and the weekly plan follow the Swiss dietary recommendations: vegetables and fruit, wholegrains, pulses, water.
Société Suisse de Nutrition SSN, OSAV (2024). Recommandations nutritionnelles suisses pour les adultes (pyramide alimentaire suisse)
Glycaemic load (GL) of a food: its glycaemic index multiplied by its available carbohydrate, divided by 100. A meal’s GL is the sum of its foods, the day’s the sum of its meals; a food without carbohydrate counts as 0.
Salmerón J, Manson JE, Stampfer MJ, Colditz GA, Wing AL, Willett WC (1997). Dietary fiber, glycemic load, and risk of non-insulin-dependent diabetes mellitus in women
Glycaemic load per serving is tabulated in the 2002 international tables, next to each food’s index.
Foster-Powell K, Holt SHA, Brand-Miller JC (2002). International table of glycemic index and glycemic load values: 2002
Glycaemic index values come from the published international tables (glucose = 100), food group by food group, with the source noted on every line; none is estimated by the app or by Tell me. The Table 1 averages come first, unless the 2021 update gives an average of at least three studies or foods that differs by more than 10 points: that one is then used (watermelon, lentils, boiled sweet potato, plantain).
Atkinson FS, Foster-Powell K, Brand-Miller JC (2008). International tables of glycemic index and glycemic load values: 2008
For foods missing there: the 2021 update, measured to the ISO 26642:2010 standard. A carbohydrate-rich food with no published value stays without an index, and the GL is then marked partial.
Atkinson FS, Brand-Miller JC, Foster-Powell K, Buyken AE, Goletzke J (2021). International tables of glycemic index and glycemic load values 2021: a systematic review
For one serving of a food, the University of Sydney database calls a load low up to 10, medium from 11 to 19 and high from 20: these cut-offs do not apply to a whole meal, so the app shows only the number there. For a day there is no official cut-off: low below 80 and high above 120 are guide values used in nutrition studies.
University of Sydney, Glycemic Index Research Service (2026). Glycemic Index Database
A guide, not a measurement: the same white bread, tested three times in 63 healthy adults, varied by about 20% within a person and 25% between people; cooking and ripeness change the index too. Not a tool for managing diabetes.
Matthan NR, Ausman LM, Meng H, Tighiouart H, Lichtenstein AH (2016). Estimating the reliability of glycemic index values and potential sources of methodological and biological variability
Water
Water: 24 ml per kilo, from drinks only (water in food is not logged). For 70 kg that is 1.7 litres: in line with EFSA’s 2 to 2.5 litres of total water, food included.
EFSA, Panel on Dietetic Products, Nutrition and Allergies (2010). Scientific Opinion on Dietary Reference Values for water
On sport days the target adds 5 dl per half hour of training, 2 litres at most. Drinking before, during and after exercise to replace sweat is the ACSM recommendation; the amount varies from person to person.
American College of Sports Medicine; Sawka MN, Burke LM, Eichner ER, et al. (2007). American College of Sports Medicine position stand. Exercise and fluid replacement
Beer and cider up to 5% ABV count towards the water you drink like water: a lager makes you pass no more urine than water over the next four hours.
Maughan RJ, Watson P, Cordery PA, Walsh NP, Oliver SJ, Dolci A, Rodriguez-Sanchez N, Galloway SD (2016). A randomized trial to assess the potential of different beverages to affect hydration status: development of a beverage hydration index
Wine and spirits don’t count towards the water you drink: for the same amount of alcohol they increase urine output in the first hours, 5% beer does not. The strength comes from the label, otherwise from the food.
Polhuis KCMM, Wijnen AHC, Sierksma A, Calame W, Tieland M (2017). The Diuretic Action of Weak and Strong Alcoholic Beverages in Elderly Men: A Randomized Diet-Controlled Crossover Trial
Vitamins and minerals
Vitamin and mineral targets (calcium, iron, magnesium, potassium, zinc, selenium, iodine, vitamins A, B12, C, D, E, folate) are the D-A-CH reference values for adults, by sex, in their latest version.
D-A-CH: DGE, ÖGE, SGE (seit 2022: DGE/ÖGE) (2015–2025). Referenzwerte für die Nährstoffzufuhr
Vitamin E: 8 mg a day for men and women, the value revised in 2025 by the DGE and ÖGE (instead of 11 to 15 mg). Since 2015 EFSA has kept 13 mg (men) and 11 mg (women): the app follows the more recent reference.
Deutsche Gesellschaft für Ernährung (DGE), Österreichische Gesellschaft für Ernährung (ÖGE) (2025). Referenzwerte für die Nährstoffzufuhr: Vitamin E
Iron: 11 mg a day for men; for women, 16 mg up to age 50 and 14 mg from 51, the age the app takes for menopause (2023 revision).
Deutsche Gesellschaft für Ernährung (DGE), Österreichische Gesellschaft für Ernährung (ÖGE) (2023). Referenzwerte für die Nährstoffzufuhr: Eisen
Zinc: the reference depends on the phytate in your diet (whole grains, pulses). The app uses the medium intake of a varied diet: 14 mg a day for men, 8 mg for women.
Deutsche Gesellschaft für Ernährung (DGE), Österreichische Gesellschaft für Ernährung (ÖGE), Schweizerische Gesellschaft für Ernährung (SGE) (2019). Referenzwerte für die Nährstoffzufuhr: Zink
Selenium: 70 µg a day for men, 60 µg for women, the D-A-CH estimated values from 2015.
Deutsche Gesellschaft für Ernährung (DGE), Österreichische Gesellschaft für Ernährung (ÖGE), Schweizerische Gesellschaft für Ernährung (SGE) (2015). Referenzwerte für die Nährstoffzufuhr: Selen
Iodine: 150 µg a day for every adult, men and women alike, the DGE reference value revised in 2025.
Deutsche Gesellschaft für Ernährung (DGE), Österreichische Gesellschaft für Ernährung (ÖGE) (2025). Referenzwerte für die Nährstoffzufuhr: Jod
Omega-3: 1.6 g a day for men, 1.1 g for women, the adequate intake of alpha-linolenic acid.
Institute of Medicine, Food and Nutrition Board (National Academies) (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids
EPA + DHA, the omega-3s found in fish: 250 mg a day, the EFSA adequate intake.
EFSA, Panel on Dietetic Products, Nutrition and Allergies (2010). Scientific Opinion on Dietary Reference Values for fats, including saturated fatty acids, polyunsaturated fatty acids, monounsaturated fatty acids, trans fatty acids, and cholesterol
Menopause declared: calcium raised to 1,200 mg a day, the reference value for women over 50.
Institute of Medicine, Food and Nutrition Board (National Academies) (2011). Dietary Reference Intakes for Calcium and Vitamin D
Sport and recovery
A session’s calories: the activity’s metabolic equivalent (MET) × weight × duration, using the METs of the 2024 Compendium of Physical Activities.
Herrmann SD, Willis EA, Ainsworth BE, et al. (2024). 2024 Adult Compendium of Physical Activities: A third update of the energy costs of human activities
Swimming: calories are counted from the duration, with the MET for the pace from the Compendium (slow crawl 5.8, medium 8, fast 10.5). A distance logged without a duration is counted at a slow pace, the assumption that gives the fewest calories.
Herrmann SD, Willis EA, Ainsworth BE, et al. (Compendium of Physical Activities) (2024). 2024 Adult Compendium of Physical Activities: Water Activities (codes 18240, 18290, 18280, 18292)
Walking logged with a distance: 0.5 kcal per kilo per kilometre, the net cost of level walking in the ACSM metabolic equation (0.1 ml of oxygen per kilo per metre).
Hata K, Yanagiya T, Noro H, Suzuki Y (2024). Hata-Yanagiya physical activity calculation system: a novel global positioning system-based method for accurate estimation of oxygen consumption during walking and running
Running logged with a distance: about 0.9 kcal per kilo per kilometre, close to the classic cost of about 1 kcal/kg/km.
Margaria R, Cerretelli P, Aghemo P, Sassi G (1963). Energy cost of running
Running logged with distance and climb: 100 m up counts as 750 m on the flat, the middle of Minetti’s measurements (0.66 to 0.83 km at 10 to 30 % gradients). Descent is not subtracted.
Minetti AE, Moia C, Roi GS, Susta D, Ferretti G (2002). Energy cost of walking and running at extreme uphill and downhill slopes
After a session: 0.3 g of protein per kilo within two hours, between 20 and 40 g.
Jäger R, Kerksick CM, Campbell BI, et al. (International Society of Sports Nutrition) (2017). International Society of Sports Nutrition Position Stand: protein and exercise
After more than an hour of endurance exercise: 1 g of carbohydrate per kilo at the next meal, to refill your stores.
Thomas DT, Erdman KA, Burke LM (Academy of Nutrition and Dietetics, Dietitians of Canada, American College of Sports Medicine) (2016). American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance
Water after a session follows the same rule as the gauge on the home screen: 5 dl per half hour of exercise.
American College of Sports Medicine; Sawka MN, Burke LM, Eichner ER, et al. (2007). American College of Sports Medicine position stand. Exercise and fluid replacement
Goal plan: running volume rises by 10 % a week at most, with a lighter week (−25 %) every 3 or 4; beyond about 30 % in two weeks, injury risk goes up. Less than 70 % of a week done: the next one keeps the same load.
Nielsen RO, Parner ET, Nohr EA, Sørensen H, Lind M, Rasmussen S (2014). Excessive progression in weekly running distance and risk of running-related injuries: an association which varies according to type of injury
About 80 % of the time at easy endurance and 20 % at most at intensity: one quality session a week on 3 days, two on 4 or 5 days, never two hard days in a row.
Seiler S (2010). What is best practice for training intensity and duration distribution in endurance athletes?
Taper: in the last 1 to 3 weeks (depending on the race), volume drops by 40 to 60 % while some intensity stays, so you arrive fresh on race day.
Bosquet L, Montpetit J, Arvisais D, Mujika I (2007). Effects of tapering on performance: a meta-analysis
When the target time is ambitious, the realistic time offered comes from your best recent run of 3 km or more, using Riegel’s formula (time × distance ratio to the power 1.06). An estimate, never a promise.
Riegel PS (1981). Athletic records and human endurance
Goal plan, carbohydrates for the day by the session’s real load, in grams per kilo: easy run of an hour or less, or rest, no change; quality session 5 (under an hour) or 6; long run 6 (60 to 90 minutes) or 7 (beyond); day after the race 6. Protein stays the same; fat drops first, down to 20 % of calories, then the budget may rise by 10 % at most (race day: maintenance + 15 % at most; loading days: see the next line): the carbs shown are those that fit in that budget. Above a BMI of 25, the app counts grams per kilo on the weight at a BMI of 25: a cautious choice by the app, not a recommendation from the source.
Thomas DT, Erdman KA, Burke LM (Academy of Nutrition and Dietetics, Dietitians of Canada, American College of Sports Medicine) (2016). American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance
Before a half, the day before; before a marathon, the two days before: carbohydrate loading, 7 g per kilo (half) or 8 g per kilo (marathon). On those days fat goes down to 0.7 g per kilo or 15 % of calories, and the budget may reach maintenance + 40 %; the carbs shown are those that fit. Simple dishes, little fibre. For 5 and 10 km, no loading: it only helps beyond 90 minutes of effort.
Burke LM, Hawley JA, Wong SHS, Jeukendrup AE (2011). Carbohydrates for training and competition
If you are losing weight during a plan: the deficit is halved on long-run days and removed on the days around the race, so you don’t run short of energy (relative energy deficiency in sport, RED-S).
Mountjoy M, Ackerman KE, Bailey DM, Burke LM, et al. (2023). 2023 International Olympic Committee’s (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs)
In the last weeks before the taper, the shopping list suggests gels to try on your long run: your gut trains too, and nothing new on race day.
Jeukendrup AE (2017). Training the Gut for Athletes
Race plan, the morning: a meal 2 to 4 h before the start, 1 to 4 g of carbohydrates per kilo; the app suggests 3 h before and 2 g per kilo of the reference weight, little fibre, fat and protein. After the finish, as for recovery: 0.3 g of protein and 1 to 1.2 g of carbohydrates per kilo within the hour.
Thomas DT, Erdman KA, Burke LM (Academy of Nutrition and Dietetics, Dietitians of Canada, American College of Sports Medicine) (2016). American College of Sports Medicine Joint Position Statement. Nutrition and Athletic Performance
Race plan, during: under an hour, water is enough; from 1 h to 2 h 30, 30 to 60 g of carbohydrates per hour (the app aims for 45); beyond, up to 90 g per hour with a glucose + fructose mix, only if tested in training (the app aims for 60, without the 90 g line in the cautious version). A 25 g gel by default (20 to 40), the first around 30 or 40 min, nothing in the last 10 minutes; under 70 min, a single gel can be enough.
Jeukendrup A (2014). A step towards personalized sports nutrition: carbohydrate intake during exercise
Race plan, drinking: to thirst, about 400 to 800 ml per hour, never gaining weight during the race (risk of hyponatraemia). Beyond 2 h or in strong heat, a salted sports drink; no amount of salt is prescribed.
American College of Sports Medicine; Sawka MN, Burke LM, Eichner ER, et al. (2007). American College of Sports Medicine position stand. Exercise and fluid replacement
Before creating a plan, a question based on the PAR-Q+ (heart, chest pain, fainting, medical advice): a yes suggests talking to a doctor, and the plan stays at easy endurance.
Warburton DER, Jamnik VK, Bredin SSD, Gledhill N (2011). The Physical Activity Readiness Questionnaire for Everyone (PAR-Q+) and Electronic Physical Activity Readiness Medical Examination (ePARmed-X+)
Alcohol
Blood alcohol is estimated with the Widmark formula, and the app only shows a range (± 30%), never an exact figure: these calculations are uncertain. It is never a tool for deciding whether to drive.
Searle J (2015). Alcohol calculations and their uncertainty
The share of the body in which alcohol is diluted comes from total body water, estimated with the Watson equations (sex, age, height, weight).
Watson PE, Watson ID, Batt RD (1980). Total body water volumes for adult males and females estimated from simple anthropometric measurements
The liver eliminates alcohol at 0.10 to 0.20 ‰ an hour: the app calculates both extremes.
Jones AW (2010). Evidence-based survey of the elimination rates of ethanol from blood with applications in forensic casework
Food composition
Nutritional values come first from the Swiss Food Composition Database of the FSVO.
Office fédéral de la sécurité alimentaire et des affaires vétérinaires (OSAV) (2026). Base de données suisse des valeurs nutritives, v7.1
For foods missing from the Swiss database: the Ciqual table of the French agency Anses.
Anses (Agence nationale de sécurité sanitaire de l’alimentation, de l’environnement et du travail) (2020). Table de composition nutritionnelle des aliments Ciqual
Scanned products: Open Food Facts, an open, collaborative database. A food found nowhere is estimated by the app and marked as an estimate.
Open Food Facts (2026). Open Food Facts
Health safeguards
The budget never falls below your basal metabolic rate, nor below 1,200 kcal (women) or 1,500 kcal (men), a threshold not to cross without medical supervision. If the meals you log stay well below it, the app tells you.
Harvard Health Publishing (Harvard Medical School) (2024). Calorie counting made easy
More than a kilo lost a week for three weeks: the app suggests slowing down, because beyond that you also lose muscle.
NHS (National Health Service, UK) (2026). Overweight and obesity in adults – Treatment
Self-induced vomiting, laxatives, repeated fasting, fear of eating: the app stops giving weight-loss figures and points you to a doctor or a dietitian.
National Institute for Health and Care Excellence (NICE) (2017). Eating disorders: recognition and treatment (NG69)
Pregnancy or breastfeeding declared: no deficit, maintenance plus the EFSA allowance, +70, +260, then +500 kcal a day by trimester, worked out from the due date (+260 without a date), +500 kcal when breastfeeding. No fasting.
EFSA, Panel on Dietetic Products, Nutrition and Allergies (2013). Scientific Opinion on Dietary Reference Values for energy
During pregnancy the alcohol target is zero: the WHO notes that no level of alcohol consumption is risk-free.
World Health Organization (WHO) (2024). Alcohol (fact sheet)