There are countless recipes for eating, and just as many workout routines to follow.

But many people find that when you try to combine the two, it becomes tricky to get right. Eating normally while exercising just doesn't seem to get you the body you want—whether you're trying to build muscle or lose fat, it feels so hard... If you eat more and exercise, you might accidentally fall into the “exercise more, gain more weight” cycle? (High exercise volume leads to high food intake). Exercise plus eating less is unsustainable for more than a few days. Even if you manage to stick with it, you might find your strength has dropped, your muscles have diminished, and you feel lost... This article will solve this problem for you:

1. How much should you eat? First, calculate these two numbers

Before calculating your ideal calorie intake, understand two concepts: BMR (Basal Metabolic Rate) and TDEE (Total Daily Energy Expenditure).

BMR refers to your energy metabolism rate at rest, unaffected by muscle activity, temperature, food intake, or stress [1]. Simply put, it's the calories you burn lying flat all day without eating or drinking. The formula is:

BMR (Male) = (13.7 × Weight (kg)) + (5.0 × Height (cm)) - (6.8 × Age) + 66

BMR (Female) = (9.6 × Weight (kg)) + (1.8 × Height (cm)) - (4.7 × Age) + 655

TDEE refers to the total daily energy expenditure, since humans don't survive without eating or drinking.

Therefore, a person's daily calorie expenditure is calculated by adding BMR to the thermic effect of food (TEF) – the calories burned during digestion and absorption – plus non-exercise activity thermogenesis (NEAT) – activities like walking, climbing stairs, fetching water, and talking. If you exercise, add the thermic effect of activity (TEA) as well.

For a quick estimate of daily calorie burn including exercise, use these activity factor guidelines:

Sedentary lifestyle: TDEE = 1.2 × BMR

1–3 days of light exercise weekly: TDEE = 1.375 × BMR

Moderate activity (more standing/walking, 3–5 days of moderate exercise weekly): TDEE = 1.55 × BMR

Primarily standing/walking with 6-7 days of high-intensity exercise weekly: TDEE = 1.725 × BMR

Nearly daily high-intensity exercise (e.g., manual labor): TDEE = 1.9 × BMR

The number you arrive at represents your daily calorie expenditure. Next, set your daily intake based on your goal:

Fat loss = Create a calorie deficit by consuming fewer calories than TDEE

Muscle gain = Create a calorie surplus by consuming more calories than TDEE

Maintain physique = Consume roughly the same amount as TDEE

Important note: Avoid rushing results by creating an excessive calorie deficit!! Gradually increasing the daily deficit—around 500 kcal is an effective starting point.

After all, consuming too few calories deprives the body of sufficient energy to maintain normal physiological functions. This can negatively impact metabolism, immune function, bone health, menstrual cycles, and more.

2. How to pair a calorie deficit with balanced nutrition?

Calorie counting alone isn't enough—you must also balance the three macronutrients (carbohydrates, protein, fat).

Carbohydrates: Essential for active individuals! Consume within 2 hours post-workout.

First, never eliminate carbohydrates entirely—especially if your training intensity is high.

As glycogen stores deplete, sustaining high-intensity exercise becomes increasingly difficult [3]. Low glycogen levels before exercise can lead to muscle glycogen depletion, impaired muscle contraction, glycogenolysis, and protein breakdown [4]. If you feel weak or dizzy during heavy lifting, this could be the cause. Research shows consuming a recovery meal within 2 hours post-workout significantly enhances recovery[5]. For muscle gain or maintenance, never miss this “golden window” for replenishment. For fat loss, moderately reduce post-workout carbs to prevent excessive glycogen storage.

Protein: More isn't always better! Choose easily digestible sources and consume appropriately.

For athletes, the benefits of protein are well-established: Consuming protein with meals 3-4 hours before exercise supports muscle growth and recovery, especially when combined with resistance training [7]. Post-workout protein intake also muscle protein synthesis and connective tissue repair. The general recommended protein intake is 0.8g-1.2g per kilogram of body weight. For athletes, protein intake can be appropriately increased beyond just satisfying hunger, maintaining muscle, and supporting muscle growth. Those aiming to reduce body fat are also encouraged to consume more protein!

A 2016 study found that over 4 weeks, participants consuming 2.4g/kg of protein daily preserved more lean body mass and lost more fat compared to those consuming 1.2g/kg, while maintaining identical exercise intensity and caloric deficit [8].

However, more protein isn't always better—its type and absorption rate matter significantly:

On one hand, animal proteins containing essential amino acids are generally superior to plant proteins. For vegetarians or those with limited meat access, soy protein offers better absorption than other plant proteins [9]. On the other hand, distributing protein evenly across meals enhances muscle protein synthesis (MPS) efficiency [10].

3. Less fat isn't necessarily better

Fat intake isn't about minimizing consumption. In fact, moderate fat intake not only helps regulate hormone levels but also plays a role in fueling endurance activities.

Research indicates that when exercise oxygen uptake reaches 65% VO₂ max—such as during long-distance jogging or similar endurance activities—the proportion of triglycerides (intramuscular fat) consumed in skeletal muscle is highest .

At this point, glycogen—the body's primary energy source—is gradually depleted. Intramuscular fat is then oxidized into energy through extensive oxygen intake, ensuring sustained performance during prolonged exercise.

Additionally, omega-3 fatty acids (a “good fat” abundant in nuts, avocados, and deep-sea fish) act as polyunsaturated fats that help delay the onset of muscle soreness, enhance anaerobic endurance, and support skeletal muscle health [11]. It is generally recommended that athletes derive 20%-35% of their total caloric intake from fats, with saturated fat intake below 10% [12].

May you find the approach that best suits you to maintain your physique and overall health.

References:

【1】Trexler, E. T., Smith-Ryan, A. E., & Norton, L. E. (2014). Metabolic adaptation to weight loss: implications for the athlete. Journal of the International Society of Sports Nutrition, 11(1), 7. https://doi.org/10.1186/1550-2783-11-7

【2】Wasserfurth, P., Palmowski, J., Hahn, A., & Krüger, K. (2020). Reasons for and Consequences of Low Energy Availability in Female and Male Athletes: Social Environment, Adaptations, and Prevention. Sports medicine - open, 6(1), 44. https://doi.org/10.1186/s40798-020-00275-6

【3】Gonzalez, D. E., McAllister, M. J., Waldman, H. S., Ferrando, A. A., Joyce, J., Barringer, N. D., Dawes, J. J., Kieffer, A. J., Harvey, T., Kerksick, C. M., Stout, J. R., Ziegenfuss, T. N., Zapp, A., Tartar, J. L., Heileson, J. L., VanDusseldorp, T. A., Kalman, D. S., Campbell, B. I., Antonio, J., & Kreider, R. B. (2022). International society of sports nutrition position stand: tactical athlete nutrition. Journal of the International Society of Sports Nutrition, 19(1), 267–315. https://doi.org/10.1080/15502783.2022.2086017

【4】Ghazzawi HA, Hussain MA, Raziq KM, Alsendi KK, Alaamer RO, Jaradat M, et al.. Exploring the relationship between micronutrients and athletic performance: A comprehensive scientific systematic review of the literature in sports medicine. Sports. (2023) 11:109. doi: 10.3390/sports1106010

【5】Romano-Ely BC, Todd MK, Saunders MJ, Laurent TST. Effect of an isocaloric carbohydrate-protein-antioxidant drink on cycling performance. Med Sci Sports Exerc. (2006) 38:1608–16. doi: 10.1249/01.mss.0000229458.11452.e9

【6】Bishop PA, Jones E, Woods AK. Recovery from training: a brief review: brief review. J Strength Cond Res. (2008) 22:1015–24. doi: 10.1519/JSC.0b013e31816eb518

【7】Moore DR. Nutrition to support recovery from endurance exercise: Optimal carbohydrate and protein replacement. Curr Sports Med Rep. (2015) 14:294–300. doi: 10.1249/JSR.0000000000000180

【8】Longland TM, Oikawa SY, Mitchell CJ, Devries MJ, Phillips SM. Higher compared with lower dietary protein during an energy deficit combined with intense exercise promotes greater lean mass gain and fat mass loss: a randomized trial. Am J Clin Nutr. 2016;103:738–46

【9】 Szedlak C, Robins A. Protein requirements for strength training. Strength Cond J. (2012) 34:85–91. doi: 10.1519/SSC.0b013e31826dc3c4

【10】Roberts, B. M., Helms, E. R., Trexler, E. T., & Fitschen, P. J. (2020). Nutritional Recommendations for Physique Athletes. Journal of human kinetics, 71, 79–108. https://doi.org/10.2478/hukin-2019-0096

【11】Jeromson S, Gallagher IJ, Galloway SDR, Hamilton DL. Omega-3 fatty acids and skeletal muscle health. Mar . (2015) 13:6977–7004. doi: 10.3390/md13116977

【12】Amawi, A., AlKasasbeh, W., Jaradat, M., Almasri, A., Alobaidi, S., Hammad, A. A., Bishtawi, T., Fataftah, B., Turk, N., Saoud, H. A., Jarrar, A., & Ghazzawi, H. (2024). Athletes' nutritional demands: a narrative review of nutritional requirements. Frontiers in nutrition, 10, 1331854. https://doi.org/10.3389/fnut.2023.1331854