How nærwert adjusts your macros when you exercise

When you log a workout, nærwert does more than add calories to your daily ceiling. For Plus members, it also adjusts your macro targets — protein, carbs, and fat — based on what your body actually needs to recover from that type of training.

The science shows that the energy you “give back” after exercise should not mirror your everyday macro split. A 500 kcal gym workout needs different macros than a rest day, and the right answer depends on your goal: whether you’re trying to lose weight, maintain, or build muscle and endurance.

The core insight: carbs refuel, protein repairs, fat stays flat

Exercise primarily depletes muscle glycogen — the carbohydrate stored in your muscles. To recover and perform in the next session, you need to refill that tank. That’s why the give-back energy should be carbohydrate-heavy, not split evenly across all three macros.

One thing to know first: nærwert gives back only the extra energy from a workout — the part above the everyday activity already built into your daily target. Your target already assumes a baseline activity level, so adding a whole workout on top of it would count the same effort twice. The percentages below apply to that extra energy, not to the raw number your tracker shows.

Here’s how nærwert adjusts your targets based on your goal:

Building muscle or maintaining weight

When your goal is to build muscle, gain weight, or maintain weight, nærwert gives back close to 100% of that extra workout energy. It goes:

  • Protein: a modest add to support muscle repair after the session — about 0.3 g per kg of body weight when you’re building or gaining, and a little less (~0.2 g/kg) when you’re maintaining
  • Carbohydrates: the bulk of the give-back energy, to refill glycogen and fuel your next workout
  • Fat: stays unchanged — refueling doesn’t require extra fat

Example: A 75 kg person whose gym workout adds 500 kcal of extra energy while training for muscle gain gets back roughly 500 kcal split as: +22 g protein (repair), +103 g carbs (refuel), +0 g fat. That carb-heavy approach matches how your body actually recovers.

Losing weight

Weight loss is different. A planned deficit is how you lose fat, so nærwert gives back only about 50% of that extra workout energy — enough to keep you from digging too deep a hole, but conservative enough to preserve your deficit.

That 50% eat-back is deliberately cautious for two reasons:

  1. Measurement error: Wearable devices and heart-rate estimates of energy burn are badly calibrated. A major device study found that every wrist-worn tracker exceeded 20% median error for energy expenditure, some far worse. Eating back 100% of an overestimate silently erases your deficit.
  2. Goal integrity: The deficit is what makes weight loss happen. The give-back is about harm-reduction, not undoing your plan.

The energy that does come back is protein-forward — raising protein to help preserve your lean muscle mass while you’re in a deficit. That matters most when you’re both restricting calories and training hard.

Example: The same 75 kg person in a weight-loss goal has 500 kcal of extra workout energy. nærwert gives back 250 kcal: +22 g protein (protect muscle) and +40 g carbs (a recovery snack), +0 g fat. Deficit mostly stays intact.

The guard rail: when the deficit gets too deep

If you combine a planned calorie deficit with a big burn day, you can quietly drop into what sports scientists call Low Energy Availability — too little energy left for your body’s basal functions like temperature, immunity, and recovery.

Below a threshold of about 30 kcal per kg of fat-free mass per day, your body actually down-regulates things like metabolic rate, thyroid function, and hormone production — the physiology behind the intuition that “the body lowers basic functions.”

On the weight-loss path, nærwert watches for this and surfaces a gentle nudge: “You’ve burned a lot today — consider a recovery snack so you’re not under-fueling.” Today that check is deliberately simple: it flags when the calories you’ve eaten minus the calories you’ve burned fall below your basal metabolic rate (BMR) — a coarse stand-in for the fat-free-mass threshold above. Three things have to be true before it appears: the day has to carry a real workout burn (roughly 300 kcal or more beyond your everyday movement), the day has to be far enough along to judge (from around 6 pm — before that, the meals you haven’t eaten yet are still ahead of you, not missed), and you have to have logged something. Precise energy-availability tracking is planned. It’s not a hard limit, just a flag to help you stay healthy.

It’s based on your activity type too

The intensity and duration of your workout matter, and they already shape the calorie estimate that drives your refuel: nærwert reads the type of exercise (via its metabolic equivalent, or “MET” value) and how long you did it. A 30-minute strength session is a different refuel than a 30-minute walk — the harder session burns more energy and depletes more glycogen.

Right now that flows through the calorie figure. A future refinement will base the carb recommendation directly on session duration and intensity, independent of the calorie estimate.

You can adjust it

These are evidence-based defaults, but nærwert lets you tune the eat-back fraction in your profile settings if your own experience suggests you need more or less. The factors are:

  • Your actual recovery needs (how soon is your next session?)
  • Your training history (new to exercise vs. well-adapted)
  • How accurately your device measures burns (varies widely)

This is a starting point

These recommendations are based on published sports-nutrition research for healthy adults. Use the first few weeks as feedback: if your energy, recovery, or progress isn’t what you expect, adjust gradually.

If you have a medical condition, are pregnant, are recovering from disordered eating, or are unsure what’s appropriate for you, speak with a qualified healthcare professional. nærwert is a tool to support your goals — not medical advice.

References

  • 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):501–528 (co-published in Medicine & Science in Sports & Exercise. 2016;48(3):543–568). https://pubmed.ncbi.nlm.nih.gov/26920240/ (Carbohydrate 3–12 g/kg/day by training load; post-exercise carb 1.0–1.2 g/kg/hour for ~4 hours when recovery < 8 hours; protein 1.2–2.0 g/kg/day; fat 20–35% of energy.)

  • Burke LM, Hawley JA, Wong SHS, Jeukendrup AE. Carbohydrates for training and competition. Journal of Sports Sciences. 2011;29(sup1):S17–S27.

  • Jäger R, Kerksick CM, Campbell BI, et al. ISSN Position Stand: Protein and Exercise. Journal of the International Society of Sports Nutrition. 2017;14:20. https://jissn.biomedcentral.com/articles/10.1186/s12970-017-0177-8

  • Kerksick CM, Arent S, Schoenfeld BJ, et al. ISSN Position Stand: Nutrient Timing. Journal of the International Society of Sports Nutrition. 2017;14:33.

  • 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. British Journal of Sports Medicine. 2018;52(6):376–384. https://bjsm.bmj.com/content/52/6/376

  • Helms ER, Zinn C, Rowlands DS, Brown SR. A systematic review of dietary protein during caloric restriction in resistance-trained lean athletes: a case for higher intakes. International Journal of Sport Nutrition and Exercise Metabolism. 2014;24(2):127–138.

  • Mountjoy M, Ackerman KE, Bailey DM, et al. 2023 International Olympic Committee’s (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). British Journal of Sports Medicine. 2023;57(17):1073–1097.

  • Loucks AB, Kiens B, Wright HH. Energy availability in athletes. Journal of Sports Sciences. 2011;29(sup1):S7–S15.

  • Impey SG, Hearris MA, Hammond KM, et al. Fuel for the Work Required: A Theoretical Framework for Carbohydrate Periodization and the Glycogen Threshold Hypothesis. Sports Medicine. 2018;48(5):1031–1048. https://pmc.ncbi.nlm.nih.gov/articles/PMC5889771/

  • Shcherbina A, Mattsson CM, Waggott D, et al. Accuracy in Wrist-Worn, Sensor-Based Measurements of Heart Rate and Energy Expenditure in a Diverse Cohort. Journal of Personalized Medicine. 2017;7(2):3.