Where the numbers come from
Every recommendation the app makes, the published work it comes from, and the actual values used. If you want to check our arithmetic, this page is how.
What this app is. Pushing Peak plans an athlete's eating around their training. It gives general nutrition and training information for healthy athletes aged thirteen and over.
What it is not. It is not a medical device, and it does not diagnose, treat or prevent any condition. It is not built for anyone managing a clinical condition through what they eat, including eating disorders, diabetes and food allergies. If any of that applies to you, talk to a doctor or a registered dietitian, and treat what the app says as information rather than instruction.
On the sources below. These are published, publicly available works. We are not affiliated with, endorsed by, or reviewed by any of their authors or the organisations they belong to. Reading them is how you check us, not evidence that they agree with us.
Resting energy
Daily energy starts from a resting metabolic rate estimate. For most athletes the app uses Mifflin-St Jeor [1], and cross-checks against Schofield [2] for the younger age brackets, where Mifflin was not derived.
This is a starting anchor for sanity, not the prescription. The day's macros are each prescribed on their own terms and then summed, rather than a total being divided up.
Energy from training
Session energy uses MET values from the 2011 Compendium of Physical Activities [3], keyed to how hard the session is.
| Intensity | Swimming METs | Compendium code | Other sports METs |
|---|---|---|---|
| Low, warm up or very easy | 5.0 | 18320 | 3.5 |
| Moderate, recreational | 6.0 | 18310 | 5.0 |
| High, training set | 8.3 | 18240 | 6.5 |
| Maximum, race effort | 10.0 | 18230 | 8.0 |
The swimming values are Compendium entries directly. The values for other sports are a four-step spread around the Compendium's single generic figure, which is our extension rather than something the Compendium states, and it is flagged internally for review.
Daily carbohydrate and protein
Targets are grams per kilogram of body weight per day, and they move with how hard the week is. Swimming uses ranges from a swimming-specific review [4]. Every other sport uses the joint position stand of the Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine [5].
| Mode | Swimming CHO | Swimming protein | Other sports CHO | Other sports protein |
|---|---|---|---|---|
| Basic | 4.0 to 5.0 g/kg | 1.2 to 1.4 g/kg | 3.0 to 5.0 g/kg | 1.2 to 1.4 g/kg |
| Performance | 6.0 to 8.0 g/kg | 1.4 to 1.7 g/kg | 5.0 to 8.0 g/kg | 1.4 to 1.7 g/kg |
| Performance max | 8.0 to 12.0 g/kg | 1.7 to 2.0 g/kg | 7.0 to 10.0 g/kg | 1.7 to 2.0 g/kg |
Timing around a session
Swimming timings come from the same swimming review [4]. Other sports use the International Society of Sports Nutrition position stand on nutrient timing [6].
| When | Carbohydrate | Protein | Trigger |
|---|---|---|---|
| Before, about 60 min out | 0.5 to 1.0 g/kg | none | every session |
| During | 30 to 60 g/hour | none | sessions over 60 min |
| During, extended | 60 to 90 g/hour | none | sessions over 150 min |
| After, within 90 min | 1.0 to 1.2 g/kg swimming, 0.5 to 1.2 g/kg other | 0.3 g/kg swimming, 0.25 to 0.4 g/kg other | every session |
The widely repeated "3-2-1 rule" for pre-event eating is not an evidence-based term and the app does not use it. What it uses instead is a continuum of roughly 1 to 4 g/kg across 1 to 4 hours before the session, plus a small easily digested snack inside the last half hour.
Fat
Fat is set as a share of the resting energy anchor, and it varies by the kind of day rather than being fixed. Bands are anchored to the Acceptable Macronutrient Distribution Range.
| Day type | Male | Female and other |
|---|---|---|
| Training day | 22% | 25% |
| Two sessions | 22% | 25% |
| Rest day | 32% | 35% |
That floor of 0.8 g/kg is an essential fatty acid backstop. On a low energy day the percentage alone would price fat below what the body needs, so whichever number is larger wins.
Why the bands differ by sex
The female figure is not a separate scale. It is the same band, positioned three percentage points higher and clamped so it cannot leave the acceptable range [4].
The reason is that adequate fat intake supports hormonal and menstrual function, and the cost of getting it wrong is measurable rather than theoretical. In a study of junior elite female swimmers, athletes with suppressed ovarian function saw 400 m velocity fall by 9.8% across twelve weeks, while a group with normal cyclic function improved by 8.2% over the same period [9]. The position stands we work from make the same point about energy and fat availability in female athletes [5] [10].
Fluid
Baseline and replacement figures come from the American College of Sports Medicine position stand on exercise and fluid replacement [7].
| What | Value |
|---|---|
| Daily baseline | 35 to 40 mL per kg per day |
| Before a session | 250 to 500 mL, about 30 min out |
| During, sessions over 30 min | 150 to 250 mL every 17 min |
| After | 1.5 x estimated sweat loss, within 2 hours |
Sweat loss is estimated at 700 mL per hour for swimming and 600 mL per hour for other sports.
Eating across the day
The app spreads intake across four to six eating occasions and watches the running energy balance through the day rather than only the daily total. Sustained hourly deficits of 300 to 400 kcal trigger a rebalance.
That threshold comes from work on within-day energy balance in endurance athletes [8], which found that athletes with suppressed resting metabolic rate spent more time in deficit and had larger single-hour deficits, with larger deficits associating with higher cortisol and a lower testosterone to cortisol ratio. Two people can eat the same daily total and be in very different states.
Food composition
Values for individual foods come from public food composition databases, chiefly USDA FoodData Central and Open Food Facts. In the app, each item shows which one it came from, and you can correct it when it is wrong. Crowd contributed entries disagree with each other sometimes, which is why the app shows you the source rather than presenting a single confident figure.
References
Verified against PubMed, the publisher or the DOI on 4 September 2026.
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition. 1990;51(2):241 to 247. doi:10.1093/ajcn/51.2.241. PMID 2305711.
- Schofield WN. Predicting basal metabolic rate, new standards and review of previous work. Human Nutrition: Clinical Nutrition. 1985;39 Suppl 1:5 to 41. PMID 4044297.
- Ainsworth BE, Haskell WL, Herrmann SD, et al. 2011 Compendium of Physical Activities: a second update of codes and MET values. Medicine and Science in Sports and Exercise. 2011;43(8):1575 to 1581. doi:10.1249/MSS.0b013e31821ece12. PMID 21681120.
- Domínguez R, Sánchez-Oliver AJ, Cuenca E, Jodra P, Fernandes da Silva S, Mata-Ordóñez F. Nutritional needs in the professional practice of swimming: a review. Journal of Exercise Nutrition and Biochemistry. 2017;21(4):1 to 10. doi:10.20463/jenb.2017.0030. PMC5772075.
- Thomas DT, Erdman KA, Burke LM. Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. Journal of the Academy of Nutrition and Dietetics. 2016;116(3):501 to 528. doi:10.1016/j.jand.2015.12.006. PMID 26920240. Also published as an ACSM joint position statement in Medicine and Science in Sports and Exercise. 2016;48(3):543 to 568. doi:10.1249/MSS.0000000000000852.
- Kerksick CM, Arent S, Schoenfeld BJ, Stout JR, Campbell B, Wilborn CD, et al. International Society of Sports Nutrition position stand: nutrient timing. Journal of the International Society of Sports Nutrition. 2017;14:33. doi:10.1186/s12970-017-0189-4. PMID 28919842.
- Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. American College of Sports Medicine position stand: exercise and fluid replacement. Medicine and Science in Sports and Exercise. 2007;39(2):377 to 390. doi:10.1249/mss.0b013e31802ca597. PMID 17277604.
- Fahrenholtz IL, Sjödin A, Benardot D, et al. Within-day energy deficiency and metabolic perturbation in male endurance athletes. International Journal of Sport Nutrition and Exercise Metabolism. 2018;28(4):419 to 427. doi:10.1123/ijsnem.2017-0337. PMID 29405793.
- VanHeest JL, Rodgers CD, Mahoney CE, De Souza MJ. Ovarian suppression impairs sport performance in junior elite female swimmers. Medicine and Science in Sports and Exercise. 2014;46(1):156 to 166. doi:10.1249/MSS.0b013e3182a32b72.
- Sims ST, Kerksick CM, Smith-Ryan AE, Janse de Jonge XAK, Hirsch KR, Arent SM, et al. International Society of Sports Nutrition position stand: nutritional concerns of the female athlete. Journal of the International Society of Sports Nutrition. 2023;20(1):2204066. doi:10.1080/15502783.2023.2204066.