Nutrition Plan References and Citations

Medical Disclaimer

The information provided in this application is for general informational and educational purposes only. It is not intended to be a substitute for professional medical advice, diagnosis, or treatment.

Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition, dietary changes, or nutritional program. Never disregard professional medical advice or delay seeking it because of something you have read in this application.

The nutritional recommendations provided are based on scientific research and general guidelines. Individual needs may vary based on specific health conditions, medications, and other factors. The creators of this application do not practice medicine and do not provide medical services or professional advice to users.

If you think you may have a medical emergency, call your doctor or emergency services immediately. Reliance on any information provided by this application is solely at your own risk.

This application may contain health or nutritional information that is subject to change and ongoing research. We strive to provide accurate and up-to-date information, but completeness and accuracy cannot be guaranteed.

Energy Expenditure

Resting Metabolic Rate

To estimate resting metabolic rate, Spren uses the Müller equations [1] which incorporate body composition measurements (fat-free mass, fat mass) along with demographic data (age, sex) to calculate Resting Energy Expenditure (REE), providing more accurate metabolic predictions than standard equations by accounting for individual body composition differences across various BMI categories. [2,3,4,5]


  1. Müller, M. J., Bosy-Westphal, A., Klaus, S., Kreymann, G., Lührmann, P. M., Neuhäuser-Berthold, M., Noack, R., Pirke, K. M., Platte, P., Selberg, O., & Steiniger, J. (2004). World Health Organization equations have shortcomings for predicting resting energy expenditure in persons from a modern, affluent population: generation of a new reference standard from a retrospective analysis of a German database of resting energy expenditure. The American Journal of Clinical Nutrition, 80(5), 1379-1390. https://doi.org/10.1093/ajcn/80.5.1379
  2. Aliasgharzadeh S, Mahdavi R, Asghari Jafarabadi M, Namazi N. Comparison of Indirect Calorimetry and Predictive Equations in Estimating Resting Metabolic Rate in Underweight Females. Iran J Public Health. 2015 Jun;44(6):822-9. PMID: 26258095; PMCID: PMC4524307.
  3. Noreik, M., Maurmann, M., Meier, V., Becker, I., Röhrig, G., Polidori, M. C., & Schulz, R. J. (2014). Resting energy expenditure (REE) in an old-old population: implications for metabolic stress. Experimental Gerontology, 59, 47-50. https://doi.org/10.1016/j.exger.2014.06.009
  4. Müller MJ, Geisler C, Hübers M, Pourhassan M, Braun W, Bosy-Westphal A. Normalizing resting energy expenditure across the life course in humans: challenges and hopes. Eur J Clin Nutr. 2018 May;72(5):628-637. doi: 10.1038/s41430-018-0151-9. Epub 2018 Apr 27. PMID: 29748655.
  5. Achamrah N, Jésus P, Grigioni S, Rimbert A, Petit A, Déchelotte P, Folope V, Coëffier M. Validity of Predictive Equations for Resting Energy Expenditure Developed for Obese Patients: Impact of Body Composition Method. Nutrients. 2018 Jan 10;10(1):63. doi: 10.3390/nu10010063. PMID: 29320432; PMCID: PMC5793291.

Activity and Exercise level

To calculate energy expenditure accurately, Spren separates activity thermogenesis into two distinct components: general activity level (NEAT) and structured exercise level, which allows for more precise calculations when these factors aren't linearly related (such as when someone has a sedentary job but exercises intensely, or vice versa). [6,7,8,9]


  1. Levine, J. A. (2004). Nonexercise activity thermogenesis (NEAT): Environment and biology. American Journal of Physiology-Endocrinology and Metabolism, 286(5), E675-E685. https://doi.org/10.1152/ajpendo.00562.2003
  2. Levine, J. A. (2003). Non-exercise activity thermogenesis. Proceedings of the Nutrition Society, 62(3), 667-679. https://doi.org/10.1079/PNS2003281
  3. Melanson EL. The effect of exercise on non-exercise physical activity and sedentary behavior in adults. Obes Rev. 2017 Feb;18 Suppl 1(Suppl 1):40-49. doi: 10.1111/obr.12507. PMID: 28164451; PMCID: PMC5388457.
  4. Levine, J. A., Vander Weg, M. W., Hill, J. O., & Klesges, R. C. (2006). Non-exercise activity thermogenesis: The crouching tiger hidden dragon of societal weight gain. Arteriosclerosis, Thrombosis, and Vascular Biology, 26(4), 729-736. https://doi.org/10.1161/01.ATV.0000205848.83210.73

Breastfeeding Impact on Energy Expenditure

Breastfeeding increases energy expenditure and should be considered for nursing women trying to lose weight, build muscle, or maintain their body weight. The specific impact of breastfeeding on energy expenditure can vary based on individual factors like age, body mass index, activity level, and milk supply. [10,11,12]


  1. Gunderson EP. Impact of breastfeeding on maternal metabolism: implications for women with gestational diabetes. Curr Diab Rep. 2014 Feb;14(2):460. doi: 10.1007/s11892-013-0460-2. PMID: 24402327; PMCID: PMC4146528.
  2. UPMC HealthBeat. (2023, May 22). Do you need more calories while breastfeeding? UPMC. https://share.upmc.com/2023/05/calories-while-breastfeeding/
  3. Smethers, A. D., Trabulsi, J. C., Stallings, V. A., Papas, M. A., & Mennella, J. A. (2023). Factors Affecting BMI Changes in Mothers during the First Year Postpartum. Nutrients, 15(6), 1364. https://doi.org/10.3390/nu15061364

Pace recommendations

Weight loss

Spren tailors your weight loss pace based on body composition, gender, activity level, exercise routine, hormone status, and sleep habits for healthy, sustainable results.

Research supports gradual, steady weight loss as more sustainable, fostering better eating habits while avoiding risks associated with rapid weight loss such as increased muscle loss, hormonal imbalances, and higher likelihood of weight regain [1,2,3,4,5].

Spren incorporates a safety net by preventing your calorie intake from dropping below your Caloric Floor—the minimum needed for daily function—ensuring metabolic stability [6].

Your body fat percentage and lean body mass impact how much and how rapidly fat can be lost [7]. Spren recommends individualized pace goals based on your recent body composition scans.

Recognizing sleep's impact on weight loss, Spren adjusts recommendations for those with inadequate sleep to account for reduced weight loss capacity [8].

For breastfeeding mothers, Spren recommends a slower pace to ensure sufficient caloric intake for milk production [9,10].


  1. Centers for Disease Control and Prevention. (2025, January 17). Steps for losing weight. Retrieved May 12, 2025, from https://www.cdc.gov/healthy-weight-growth/losing-weight/index.html
  2. Jaime K, Mank V. Risks Associated With Excessive Weight Loss. [Updated 2024 Feb 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK603752/
  3. Farhana A, Rehman A. Metabolic Consequences of Weight Reduction. [Updated 2023 Jul 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK572145/
  4. Sagayama H, Yoshimura E, Yamada Y, Ichikawa M, Ebine N, Higaki Y, Kiyonaga A, Tanaka H. Effects of rapid weight loss and regain on body composition and energy expenditure. Appl Physiol Nutr Metab. 2014 Jan;39(1):21-7. doi: 10.1139/apnm-2013-0096. Epub 2013 Jun 18. PMID: 24383503.
  5. Ashtary-Larky D, Bagheri R, Abbasnezhad A, Tinsley GM, Alipour M, Wong A. Effects of gradual weight loss v. rapid weight loss on body composition and RMR: a systematic review and meta-analysis. Br J Nutr. 2020 Dec 14;124(11):1121-1132. doi: 10.1017/S000711452000224X. Epub 2020 Jun 24. PMID: 32576318.
  6. National Institutes of Health. (2023, February 28). Calorie restriction, immune function, and health span. NIH Research Matters. Retrieved May 12, 2025, from https://www.nih.gov/news-events/nih-research-matters/calorie-restriction-immune-function-health-span
  7. Forbes GB. Body fat content influences the body composition response to nutrition and exercise. Ann N Y Acad Sci. 2000 May;904:359-65. doi: 10.1111/j.1749-6632.2000.tb06482.x. PMID: 10865771.
  8. Nedeltcheva AV, Kilkus JM, Imperial J, Schoeller DA, Penev PD. Insufficient sleep undermines dietary efforts to reduce adiposity. Ann Intern Med. 2010 Oct 5;153(7):435-41. doi: 10.7326/0003-4819-153-7-201010050-00006. PMID: 20921542; PMCID: PMC2951287.
  9. Smethers, A. D., Trabulsi, J. C., Stallings, V. A., Papas, M. A., & Mennella, J. A. (2023). Factors Affecting BMI Changes in Mothers during the First Year Postpartum. Nutrients, 15(6), 1364. https://doi.org/10.3390/nu15061364
  10. Academy of Nutrition and Dietetics. (2022). Losing weight while breastfeeding. Eat Right. https://www.eatright.org/health/pregnancy/breastfeeding-and-formula/losing-weight-while-breastfeeding

Building muscle

Spren's individualized pace recommendation helps you build muscle with minimal fat gain. This sustainable approach is based on body composition, gender, activity level, exercise routine, strength training experience, hormone status, and sleep habits.

Using your recent lean mass index (a measure of muscularity), Spren determines your muscle-building potential and establishes realistic pace goals [1,2]. Your training experience is also considered, as it significantly impacts muscle-building potential [3].

Recognizing sleep's crucial role in hormone production necessary for muscle growth [4,5], Spren adjusts recommendations for those with inadequate sleep and recovery.

For breastfeeding mothers, a slower pace is recommended to ensure gradual changes and prevent issues with milk production [6,7].


  1. Concordia University Health Services. (n.d.). The 4 truths about building muscle. Retrieved May 12, 2025, from https://www.concordia.ca/cunews/offices/provost/health/topics/healthy-eating/4-truths-about-building-muscle.html
  2. Henselmans, M. (n.d.). FFMI calculator: Calculate your genetic muscular potential. Retrieved May 12, 2025, from https://mennohenselmans.com/ffmi-calculator/
  3. Matthews, M. (2020, October 15). Everything you should know about newbie gains, according to science. Legion. Retrieved May 12, 2025, from https://legionathletics.com/newbie-gains/
  4. Scrimshaw NS, Habicht JP, Pellet P, Piché ML, Cholakos B. Effects of sleep deprivation and reversal of diurnal activity on protein metabolism of young men. Am J Clin Nutr. 1966 Nov;19(5):313-9. doi: 10.1093/ajcn/19.5.313. PMID: 5923588.
  5. Dattilo M, Antunes HK, Medeiros A, Mônico-Neto M, Souza Hde S, Lee KS, Tufik S, de Mello MT. Paradoxical sleep deprivation induces muscle atrophy. Muscle Nerve. 2012 Mar;45(3):431-3. doi: 10.1002/mus.22322. PMID: 22334180.
  6. Smethers, A. D., Trabulsi, J. C., Stallings, V. A., Papas, M. A., & Mennella, J. A. (2023). Factors Affecting BMI Changes in Mothers during the First Year Postpartum. Nutrients, 15(6), 1364. https://doi.org/10.3390/nu15061364
  7. Kodete, C. S., Thuraka, B., Pasupuleti, V., & Malisetty, S. (2024). Hormonal Influences on Skeletal Muscle Function in Women across Life Stages: A Systematic Review. Muscles, 3(3), 271-286. https://doi.org/10.3390/muscles3030024

Macronutrient Recommendations

Spren recommends optimal macronutrient targets based on a your body composition, age, gender, activity level, exercise routine, hormone status (i.e. breastfeeding for women), sleep quality/duration, dietary preference, and noted health conditions. We also provide an optimal range and a wider range for macronutrients so users can adjust their macros to fit their exact needs.


Protein recommendations

Your individualized protein target recommendation is based on metabolically demanding lean body mass instead of total body weight for a more accurate representation of your protein needs [1,2]. It is also adjusted to account for your dietary preference and activity and exercise demands.


Protein recommendation for weight loss

Spren's research-backed high-protein approach is designed to optimize weight loss by:

  • Preserving lean muscle mass during caloric restriction [3,4]
  • Enhancing satiety, reducing hunger and cravings, making it easier to adhere to your nutrition plan [5,6]
  • Boosting metabolism through protein's higher thermic effect, increasing calories burned [6,7]
  • Improving overall dietary satisfaction with less mood disturbance, stress, and fatigue compared to lower-protein approaches [8]

Research consistently shows higher protein intake (1.8-2.0g/kg depending on caloric deficit) helps prevent lean mass loss during weight loss for both athletes and older adults [9,10,11].


  1. Dekker, I. M., van Rijssen, N. M., Verreijen, A., Weijs, P. J. M., de Boer, W. B., Terpstra, D., & Kruizenga, H. M. (2022). Calculation of protein requirements; a comparison of calculations based on bodyweight and fat free mass. Clinical Nutrition ESPEN, 48, 378-385. https://doi.org/10.1016/j.clnesp.2022.01.014
  2. Stanzione JR, Boullata JI, Bruneau ML Jr, Volpe SL. Association between protein intake and lean body mass in a group of Masters Athletes. J Nutr Sci. 2022 Apr 27;11:e30. doi: 10.1017/jns.2022.10. PMID: 35573464; PMCID: PMC9066312.
  3. Longland TM, Oikawa SY, Mitchell CJ, Devries MC, 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 Mar;103(3):738-46. doi: 10.3945/ajcn.115.119339. Epub 2016 Jan 27. PMID: 26817506.
  4. Helms, E. R., Zinn, C., Rowlands, D. S., & Brown, S. R. (2014). 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, 24(2), 127-138. https://doi.org/10.1123/ijsnem.2013-0054
  5. Paddon-Jones, D., Westman, E., Mattes, R. D., Wolfe, R. R., Astrup, A., & Westerterp-Plantenga, M. (2008). Protein, weight management, and satiety. The American Journal of Clinical Nutrition, 87(5), 1558S-1561S. https://doi.org/10.1093/ajcn/87.5.1558S
  6. Halton, T. L., & Hu, F. B. (2004). The effects of high protein diets on thermogenesis, satiety and weight loss: a critical review. Journal of the American College of Nutrition, 23(5), 373-385. https://doi.org/10.1080/07315724.2004.10719381
  7. Johnston, C. S., Day, C. S., & Swan, P. D. (2002). Postprandial Thermogenesis Is Increased 100% on a High-Protein, Low-Fat Diet versus a High-Carbohydrate, Low-Fat Diet in Healthy, Young Women. Journal of the American College of Nutrition, 21(1), 55–61. https://doi.org/10.1080/07315724.2002.10719194
  8. Hashemi Javaheri FS, Ostadrahimi A, Nematy M, Arabi SM, Rahmani K, Amini M. The effect of a low-calorie, high-protein diet on psychometric variables in obese individuals: a Randomized Clinical Trial. Nutr Neurosci. 2024 Aug;27(8):818-825. doi: 10.1080/1028415X.2023.2261680. Epub 2023 Oct 19. PMID: 37859298.
  9. Mettler S, Mitchell N, Tipton KD. Increased protein intake reduces lean body mass loss during weight loss in athletes. Med Sci Sports Exerc. 2010 Feb;42(2):326-37. doi: 10.1249/MSS.0b013e3181b2ef8e. PMID: 19927027.
  10. Bopp, M. J., Houston, D. K., Lenchik, L., Easter, L., Kritchevsky, S. B., & Nicklas, B. J. (2008). Lean mass loss is associated with low protein intake during dietary-induced weight loss in postmenopausal women. Journal of the American Dietetic Association, 108(7), 1216-1220. https://doi.org/10.1016/j.jada.2008.04.017
  11. Kim JE, O'Connor LE, Sands LP, Slebodnik MB, Campbell WW. Effects of dietary protein intake on body composition changes after weight loss in older adults: a systematic review and meta-analysis. Nutr Rev. 2016 Mar;74(3):210-24. doi: 10.1093/nutrit/nuv065. Epub 2016 Feb 16. PMID: 26883880; PMCID: PMC4892287.

Protein recommendation for building muscle

Spren's research-backed high-protein approach is designed to optimize muscle building while minimizing fat gain through:

  • Building muscle foundation: Protein provides essential amino acids required for muscle protein synthesis, repair and growth [1]
  • Optimizing muscle development: When combined with strength training, higher protein intake (1.6–2.2 g/kg/day) maximizes muscle protein synthesis and development [2,3]
  • Minimizing fat gain: Research shows high-protein diets can minimize fat gain even with a caloric surplus, as excess protein does not preferentially convert to fat [4,5]

  1. Church DD, Hirsch KR, Park S, Kim IY, Gwin JA, Pasiakos SM, Wolfe RR, Ferrando AA. Essential Amino Acids and Protein Synthesis: Insights into Maximizing the Muscle and Whole-Body Response to Feeding. Nutrients. 2020 Dec 2;12(12):3717. doi: 10.3390/nu12123717. PMID: 33276485; PMCID: PMC7760188.
  2. Helms, E. R., Zinn, C., Rowlands, D. S., & Brown, S. R. (2014). 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, 24(2), 127-138. https://doi.org/10.1123/ijsnem.2013-0054
  3. Stokes T, Hector AJ, Morton RW, McGlory C, Phillips SM. Recent Perspectives Regarding the Role of Dietary Protein for the Promotion of Muscle Hypertrophy with Resistance Exercise Training. Nutrients. 2018 Feb 7;10(2):180. doi: 10.3390/nu10020180. PMID: 29414855; PMCID: PMC5852756.
  4. Antonio, J., Peacock, C.A., Ellerbroek, A. et al. The effects of consuming a high protein diet (4.4 g/kg/d) on body composition in resistance-trained individuals. J Int Soc Sports Nutr 11, 19 (2014). https://doi.org/10.1186/1550-2783-11-19
  5. Antonio, J., Ellerbroek, A., Silver, T. et al. A high protein diet (3.4 g/kg/d) combined with a heavy resistance training program improves body composition in healthy trained men and women – a follow-up investigation. J Int Soc Sports Nutr 12, 39 (2015). https://doi.org/10.1186/s12970-015-0100-0

Protein recommendation for maintaining body composition

Spren’s research-backed higher-protein diet recommendation is designed to maintain healthy lean mass for longevity [1].

The amino acids that makeup protein are involved in many processes in the body, including tissue growth and repair, immune function, and energy production [2]. High-protein diets help maintain higher lean muscle mass which results in a higher metabolism [3], better fat-burning capacity, improved insulin sensitivity, improved immunity to acute and chronic disease, a slowed aging process, and better bone density [4,5,6].


  1. Cava, E., Yeat, N. C., & Mittendorfer, B. (2017). Preserving healthy muscle during weight loss. Advances in Nutrition, 8(3), 511-519. https://doi.org/10.3945/an.116.014506
  2. Cleveland Clinic. (2021, December 22). Amino acids. Retrieved May 12, 2025, from https://my.clevelandclinic.org/health/articles/22243-amino-acids
  3. Dyck DJ, Heigenhauser GJ, Bruce CR. The role of adipokines as regulators of skeletal muscle fatty acid metabolism and insulin sensitivity. Acta Physiol (Oxf). 2006 Jan;186(1):5-16. doi: 10.1111/j.1748-1716.2005.01502.x. PMID: 16497175.
  4. Kim JE, O'Connor LE, Sands LP, Slebodnik MB, Campbell WW. Effects of dietary protein intake on body composition changes after weight loss in older adults: a systematic review and meta-analysis. Nutr Rev. 2016 Mar;74(3):210-24. doi: 10.1093/nutrit/nuv065. Epub 2016 Feb 16. PMID: 26883880; PMCID: PMC4892287.
  5. Paddon-Jones D, Short KR, Campbell WW, Volpi E, Wolfe RR. Role of dietary protein in the sarcopenia of aging. Am J Clin Nutr. 2008 May;87(5):1562S-1566S. doi: 10.1093/ajcn/87.5.1562S. PMID: 18469288.
  6. Phillips SM, Chevalier S, Leidy HJ. Protein "requirements" beyond the RDA: implications for optimizing health. Appl Physiol Nutr Metab. 2016 May;41(5):565-72. doi: 10.1139/apnm-2015-0550. Epub 2016 Feb 9. Erratum in: Appl Physiol Nutr Metab. 2022 May;47(5):615. doi: 10.1139/apnm-2022-0131. PMID: 26960445.

Safety of high-protein diets in healthy people

Several long-term studies show no adverse health effects from high-protein diets in healthy people [1,2].


  1. Phillips SM, Chevalier S, Leidy HJ. Protein "requirements" beyond the RDA: implications for optimizing health. Appl Physiol Nutr Metab. 2016 May;41(5):565-72. doi: 10.1139/apnm-2015-0550. Epub 2016 Feb 9. Erratum in: Appl Physiol Nutr Metab. 2022 May;47(5):615. doi: 10.1139/apnm-2022-0131. PMID: 26960445.
  2. Antonio J, Ellerbroek A, Silver T, Vargas L, Tamayo A, Buehn R, Peacock CA. A High Protein Diet Has No Harmful Effects: A One-Year Crossover Study in Resistance-Trained Males. J Nutr Metab. 2016;2016:9104792. doi: 10.1155/2016/9104792. Epub 2016 Oct 11. PMID: 27807480; PMCID: PMC5078648.

Protein recommendation for Chronic Kidney Disease

Spren follows medical guidelines that recommend lower protein targets for individuals at risk of chronic kidney disease (CKD) [1]. When users indicate CKD risk during creation of their personalized nutrition plan, protein recommendations are adjusted accordingly, as excess protein can accelerate renal failure in these individuals. For those with CKD, dietary protein is generally limited to 0.6-0.8 g/kg of body weight (0.27-0.36 g/lb), with a maximum recommendation of 0.8 g/kg (0.36 g/lb).


  1. Ko GJ, Obi Y, Tortorici AR, Kalantar-Zadeh K. Dietary protein intake and chronic kidney disease. Curr Opin Clin Nutr Metab Care. 2017 Jan;20(1):77-85. doi: 10.1097/MCO.0000000000000342. PMID: 27801685; PMCID: PMC5962279.

Carbohydrates and fats balance recommendation

Spren tailors your fat and carbohydrate balance recommendations to align with your dietary preferences while optimizing for your energy needs based on activity level and specific training modalities (e.g., strength vs. cardio)[1].

Our flexible approach is supported by extensive research showing that various dietary patterns can be effective for weight management. A 12-month weight loss study found no significant difference in weight change between healthy low-fat and healthy low-carbohydrate diets, with neither genetic factors nor baseline insulin secretion influencing results [2].

Research consistently demonstrates that flexibility in dietary approaches is beneficial:

  • A systematic review comparing 14 popular dietary programs found multiple approaches can effectively improve cardiovascular risk factors and support weight management [3]
  • Studies show that a wide range of dietary approaches—from low-fat to low-carbohydrate/ketogenic—can be similarly effective for improving body composition [4]
  • Importantly, research has found that strict, restrictive dieting is associated with higher BMI, reduced feelings of self-control, and increased psychological stress related to food intake compared to flexible dietary approaches [5].

  1. Iraki J, Fitschen P, Espinar S, Helms E. Nutrition Recommendations for Bodybuilders in the Off-Season: A Narrative Review. Sports (Basel). 2019 Jun 26;7(7):154. doi: 10.3390/sports7070154. PMID: 31247944; PMCID: PMC6680710.
  2. Gardner CD, Trepanowski JF, Del Gobbo LC, Hauser ME, Rigdon J, Ioannidis JPA, Desai M, King AC. Effect of Low-Fat vs Low-Carbohydrate Diet on 12-Month Weight Loss in Overweight Adults and the Association With Genotype Pattern or Insulin Secretion: The DIETFITS Randomized Clinical Trial. JAMA. 2018 Feb 20;319(7):667-679. doi: 10.1001/jama.2018.0245. Erratum in: JAMA. 2018 Apr 3;319(13):1386. doi: 10.1001/jama.2018.2977. Erratum in: JAMA. 2018 Apr 24;319(16):1728. doi: 10.1001/jama.2018.4854. PMID: 29466592; PMCID: PMC5839290.
  3. Ge L, Sadeghirad B, Ball GDC, da Costa BR, Hitchcock CL, Svendrovski A, Kiflen R, Quadri K, Kwon HY, Karamouzian M, Adams-Webber T, Ahmed W, Damanhoury S, Zeraatkar D, Nikolakopoulou A, Tsuyuki RT, Tian J, Yang K, Guyatt GH, Johnston BC. Comparison of dietary macronutrient patterns of 14 popular named dietary programmes for weight and cardiovascular risk factor reduction in adults: systematic review and network meta-analysis of randomised trials. BMJ. 2020 Apr 1;369:m696. doi: 10.1136/bmj.m696. Erratum in: BMJ. 2020 Aug 5;370:m3095. doi: 10.1136/bmj.m3095. PMID: 32238384; PMCID: PMC7190064.
  4. Aragon, A.A., Schoenfeld, B.J., Wildman, R. et al. International society of sports nutrition position stand: diets and body composition. J Int Soc Sports Nutr 14, 16 (2017). https://doi.org/10.1186/s12970-017-0174-y
  5. Timko CA, Perone J. Rigid and flexible control of eating behavior in a college population. Eat Behav. 2005 Feb;6(2):119-25. doi: 10.1016/j.eatbeh.2004.09.002. PMID: 15598598.

Diet Advisories

For individuals with health risk factors, additional research-backed adjustments are implemented to suggest the most suitable carb and fat balance for optimal health.


Breastfeeding and animal-based diets

Nursing while on an animal-based diet increases the risk of developing a serious condition called ketoacidosis [1,2,3,4,5,6] and may decrease milk production [7] and provide insufficient essential vitamins and minerals to your nursing child [8].

We recommend switching to a balanced diet while nursing. If you are considering an animal-based diet while nursing, you should work closely with your doctor or a lactation consultant.


  1. Frise, C. J., Mackillop, L., Joash, K., & Williamson, C. (2013). Starvation ketoacidosis in pregnancy. European Journal of Obstetrics & Gynecology and Reproductive Biology, 167(1), 1-7. https://doi.org/10.1016/j.ejogrb.2012.10.005
  2. Dalfrà, M. G., Burlina, S., Sartore, G., & Lapolla, A. (2015). Ketoacidosis in diabetic pregnancy. The Journal of Maternal-Fetal & Neonatal Medicine, 29(17), 2889–2895. https://doi.org/10.3109/14767058.2015.1107903
  3. Al Alawi AM, Al Flaiti A, Falhammar H. Lactation Ketoacidosis: A Systematic Review of Case Reports. Medicina (Kaunas). 2020 Jun 17;56(6):299. doi: 10.3390/medicina56060299. PMID: 32560535; PMCID: PMC7353886.
  4. Al Alawi AM, Falhammar H. Lactation ketoacidosis: case presentation and literature review. BMJ Case Rep. 2018 May 30;2018:bcr2017223494. doi: 10.1136/bcr-2017-223494. PMID: 29848523; PMCID: PMC5976071.
  5. Nnodum, B. N., Oduah, E., Albert, D., & Pettus, M. (2019). Ketogenic diet-induced severe ketoacidosis in a lactating woman: A case report and review of the literature. Case Reports in Nephrology, 2019, 1214208. https://doi.org/10.1155/2019/1214208
  6. Sloan G, Ali A, Webster J. A rare cause of metabolic acidosis: ketoacidosis in a non-diabetic lactating woman. Endocrinol Diabetes Metab Case Rep. 2017 Sep 4;2017:17-0073. doi: 10.1530/EDM-17-0073. PMID: 28924478; PMCID: PMC5592701.
  7. Bonyata, K. (n.d.). Low carb diets and breastfeeding. KellyMom. Retrieved May 12, 2025, from https://kellymom.com/nutrition/mothers-diet/mom-lowcarb/
  8. Rocky Mountain Children's Health Foundation. (2019, October 1). Keto and breastfeeding: Is it a good idea? RMCC. Retrieved May 12, 2025, from https://rmccares.org/2019/10/01/keto-and-breastfeeding-is-it-a-good-idea/

Chronic Kidney Disease (CKD) and animal-based diets

There is conflicting research showing the safety of an animal-based diet for people with a risk of chronic kidney disease [1,2,3].

Spren follows medical guidelines that recommend lower protein targets for individuals at risk of chronic kidney disease (CKD) [4]. When users indicate CKD risk during creation of their personalized nutrition plan, protein recommendations are adjusted accordingly, as excess protein can accelerate renal failure in these individuals. For those with CKD, dietary protein is generally limited to 0.6-0.8 g/kg of body weight (0.27-0.36 g/lb), with a maximum recommendation of 0.8 g/kg (0.36 g/lb).

Always consult your healthcare team when starting a new diet.


  1. Mafra D, Borges NA, Cardozo LFMF, Anjos JS, Black AP, Moraes C, Bergman P, Lindholm B, Stenvinkel P. Red meat intake in chronic kidney disease patients: Two sides of the coin. Nutrition. 2018 Feb;46:26-32. doi: 10.1016/j.nut.2017.08.015. Epub 2017 Sep 19. PMID: 29290351.
  2. Schieszer, J. (2021, August 19). The potential dangers of ketogenic diets in kidney disease. Renal & Urology News. Retrieved May 12, 2025, from https://www.renalandurologynews.com/features/ketogenic-diet-potentially-harmful-especially-in-patients-with-ckd/
  3. Crosby L, Davis B, Joshi S, et al. Ketogenic diets and chronic disease: Weighing the benefits against the risks. Front Nutr. Published online July 16, 2021. doi:10.3389/fnut.2021.702802
  4. Ko GJ, Obi Y, Tortorici AR, Kalantar-Zadeh K. Dietary protein intake and chronic kidney disease. Curr Opin Clin Nutr Metab Care. 2017 Jan;20(1):77-85. doi: 10.1097/MCO.0000000000000342. PMID: 27801685; PMCID: PMC5962279.

Breastfeeding and a ketogenic diet

Nursing while on a ketogenic diet increases the risk of developing a serious condition called ketoacidosis [1,2,3,4,5,6] and may decrease milk production [7].

We recommend switching to a balanced diet while nursing. If you are considering a ketogenic diet while nursing, you should work closely with your doctor or a lactation consultant.


  1. Frise, C. J., Mackillop, L., Joash, K., & Williamson, C. (2013). Starvation ketoacidosis in pregnancy. European Journal of Obstetrics & Gynecology and Reproductive Biology, 167(1), 1-7. https://doi.org/10.1016/j.ejogrb.2012.10.005
  2. Dalfrà, M. G., Burlina, S., Sartore, G., & Lapolla, A. (2015). Ketoacidosis in diabetic pregnancy. The Journal of Maternal-Fetal & Neonatal Medicine, 29(17), 2889–2895. https://doi.org/10.3109/14767058.2015.1107903
  3. Al Alawi AM, Al Flaiti A, Falhammar H. Lactation Ketoacidosis: A Systematic Review of Case Reports. Medicina (Kaunas). 2020 Jun 17;56(6):299. doi: 10.3390/medicina56060299. PMID: 32560535; PMCID: PMC7353886.
  4. Al Alawi AM, Falhammar H. Lactation ketoacidosis: case presentation and literature review. BMJ Case Rep. 2018 May 30;2018:bcr2017223494. doi: 10.1136/bcr-2017-223494. PMID: 29848523; PMCID: PMC5976071.
  5. Nnodum, B. N., Oduah, E., Albert, D., & Pettus, M. (2019). Ketogenic diet-induced severe ketoacidosis in a lactating woman: A case report and review of the literature. Case Reports in Nephrology, 2019, 1214208. https://doi.org/10.1155/2019/1214208
  6. Sloan G, Ali A, Webster J. A rare cause of metabolic acidosis: ketoacidosis in a non-diabetic lactating woman. Endocrinol Diabetes Metab Case Rep. 2017 Sep 4;2017:17-0073. doi: 10.1530/EDM-17-0073. PMID: 28924478; PMCID: PMC5592701.
  7. Bonyata, K. (n.d.). Low carb diets and breastfeeding. KellyMom. Retrieved May 12, 2025, from https://kellymom.com/nutrition/mothers-diet/mom-lowcarb/

Chronic Kidney Disease (CKD) and a ketogenic diet

There is conflicting research showing the safety of a Ketogenic diet for people with a risk of chronic kidney disease [1,2].

Spren follows medical guidelines that recommend lower protein targets for individuals at risk of chronic kidney disease (CKD) [3]. When users indicate CKD risk during creation of their personalized nutrition plan, protein recommendations are adjusted accordingly, as excess protein can accelerate renal failure in these individuals. For those with CKD, dietary protein is generally limited to 0.6-0.8 g/kg of body weight (0.27-0.36 g/lb), with a maximum recommendation of 0.8 g/kg (0.36 g/lb).

Always consult your healthcare team when starting a new diet.


  1. Schieszer, J. (2021, August 19). The potential dangers of ketogenic diets in kidney disease. Renal & Urology News. Retrieved May 12, 2025, from https://www.renalandurologynews.com/features/ketogenic-diet-potentially-harmful-especially-in-patients-with-ckd/
  2. Crosby L, Davis B, Joshi S, et al. Ketogenic diets and chronic disease: Weighing the benefits against the risks. Front Nutr. Published online July 16, 2021. doi:10.3389/fnut.2021.702802
  3. Ko GJ, Obi Y, Tortorici AR, Kalantar-Zadeh K. Dietary protein intake and chronic kidney disease. Curr Opin Clin Nutr Metab Care. 2017 Jan;20(1):77-85. doi: 10.1097/MCO.0000000000000342. PMID: 27801685; PMCID: PMC5962279.

Metabolic conditions and low-fat diets

Studies indicate that metabolic conditions like hypertension, diabetes or pre-diabetes, and elevated cholesterol show significant improvement with a low-carbohydrate diet [1,2,3,4].

If a user selects a low-fat diet, we recommend switching to a low-carbohydrate diet and reducing saturated fats. Always consult your healthcare team when starting a new diet.


  1. Santos FL, Esteves SS, da Costa Pereira A, Yancy WS Jr, Nunes JP. Systematic review and meta-analysis of clinical trials of the effects of low carbohydrate diets on cardiovascular risk factors. Obes Rev. 2012 Nov;13(11):1048-66. doi: 10.1111/j.1467-789X.2012.01021.x. Epub 2012 Aug 21. PMID: 22905670.
  2. Unwin DJ, Tobin SD, Murray SW, Delon C, Brady AJ. Substantial and Sustained Improvements in Blood Pressure, Weight and Lipid Profiles from a Carbohydrate Restricted Diet: An Observational Study of Insulin Resistant Patients in Primary Care. Int J Environ Res Public Health. 2019 Jul 26;16(15):2680. doi: 10.3390/ijerph16152680. PMID: 31357547; PMCID: PMC6695889.
  3. Duke Health. (2010, January 25). Low-carb diet effective at lowering blood pressure. Retrieved May 12, 2025, from https://corporate.dukehealth.org/news/low-carb-diet-effective-lowering-blood-pressure
  4. Hobbs, H. (2025, March 26). 23 studies on low carb and low fat diets — Time to retire the fad. Healthline. Retrieved May 12, 2025, from https://www.healthline.com/nutrition/23-studies-on-low-carb-and-low-fat-diets

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