How is JustProtein App different from calorie-tracking apps that also track protein?

Most calorie-tracking apps focus on weight loss and total calories. JustProtein is designed specifically for women, with a focus on protein quantity and quality, amino acids, and life stage (including perimenopause and menopause). It helps you understand whether you are eating enough high-quality protein across the day, not just counting macros.

Why is tracking protein important? Isn’t it obvious what I eat?

Many women feel like they eat plenty of protein, but when they track it, they discover they are 30–50% below what their body actually needs. Tracking shows how much protein you are truly getting, whether it is spread through the day, and whether your meals contain enough high-quality protein to support muscle, metabolism, and energy.

Do I need to track my protein every day?

No, you don’t have to track forever. Most women only need to track for about 7–14 days to see their real intake and spot patterns. After that, occasional check-ins are enough to stay on track and make sure your meals still match your protein goals.

How much protein do you need to build muscle?

Research suggests most women do better with more protein than the old 0.8 g per kilogram guideline, especially after age 40. A simple target is to aim for around 2 grams of protein per kilogram of body weight per day (about 1 gram per pound), while JustProtein personalizes this range based on your age, activity level, diet type, and goals. Always speak with your healthcare provider if you have medical conditions or kidney issues.

Why is protein so important for women?

Protein is essential for building and preserving muscle, supporting bone health, making hormones and enzymes, stabilizing blood sugar, and keeping you full and energized. For women, especially those juggling busy lives and hormonal shifts, getting enough protein helps protect strength, metabolism, and long-term health.

What are the benefits of a high-protein diet for women over 40?

A high-protein diet is especially beneficial for women over 40 because it helps counteract natural muscle loss, supports metabolism, and stabilizes blood sugar. As estrogen declines during perimenopause and menopause, the body becomes less efficient at building and maintaining muscle, making protein even more essential. A higher-protein diet can help women preserve and build lean muscle, support metabolism and healthy weight, stabilize blood sugar and reduce cravings, improve bone health and reduce osteoporosis risk, enhance energy and mood, and improve recovery and reduce inflammation. Modern research shows women in midlife often need more protein than outdated guidelines suggest. JustProtein helps you find the right amount based on your age, stage of life, and diet type.

Is protein good for female hormones?

Protein provides the amino acids your body uses to build many hormones and to support enzymes involved in hormone balance. Eating enough protein also helps stabilize blood sugar and reduce big glucose swings, which can influence how you feel throughout your cycle and during perimenopause and menopause. It is not a cure-all, but it is a strong foundation for hormonal health.

What is high-quality protein and why does it matter?

High-quality protein contains all nine essential amino acids in good amounts, is easy to digest, and provides enough leucine to stimulate muscle protein synthesis. Examples include eggs, dairy, fish, poultry, meat, and well-planned combinations of plant proteins. Focusing on high-quality protein means your body can actually use what you eat to build muscle, support bones, and repair tissues.

Can a high-protein diet help with managing blood sugar and metabolism?

Yes, higher-protein meals can slow digestion, blunt blood sugar spikes, and keep you fuller for longer, which may reduce cravings and support more stable energy. Over time, preserving and building muscle with adequate protein can also support a healthier metabolism. This should be part of an overall lifestyle plan and not a substitute for medical care if you have diabetes or other conditions.

I’m vegan or mostly plant-based. Can I still hit my protein goals?

Absolutely. Vegan and plant-based eaters can meet their protein needs by being more intentional about sources and combinations. You may need slightly more total protein and a focus on foods like tofu, tempeh, lentils, beans, quinoa, and soy or pea-based products. JustProtein helps you see whether your plant-based meals provide enough total protein and essential amino acids.

The Science of Protein: Myths, Facts, and Impact After 40

Why protein needs change after 40

Why age-related muscle loss accelerates after midlife
- Sarcopenia: revised European consensus on definition and diagnosis. Cruz-Jentoft AJ, Bahat G, Bauer J, et al. Age and Ageing (2019). https://doi.org/10.1093/ageing/afy169
- Sarcopenia: definition, epidemiology, and pathophysiology. Kim TN, Choi KM. Journal of Bone Metabolism (2013). https://doi.org/10.11005/jbm.2013.20.1.1
- Sarcopenia as a risk factor for falls in elderly individuals: results from the ilSIRENTE study. Landi F, Liperoti R, Russo A, et al. Clinical Nutrition (2012). https://doi.org/10.1016/j.clnu.2012.02.007
Read our blog on Why protein needs change after 40
Why the same protein intake no longer triggers muscle repair
- Anabolic signaling deficits underlie amino acid resistance of wasting, aging muscle. Cuthbertson D, Smith K, Babraj J, et al. FASEB Journal (2005). https://doi.org/10.1096/fj.04-2640fje
- The response of muscle protein anabolism to combined hyperaminoacidemia and glucose-induced hyperinsulinemia is impaired in the elderly. Volpi E, Mittendorfer B, Rasmussen BB, Wolfe RR. Journal of Clinical Endocrinology & Metabolism (2000). https://doi.org/10.1210/jcem.85.12.7021
- Alterations in human muscle protein metabolism with aging: protein and exercise as countermeasures. Churchward-Venne TA, Breen L, Phillips SM. BioFactors (2014). https://doi.org/10.1002/biof.1138

Muscle: a longevity powerhouse

Why preserving muscle matters beyond appearance
- Low relative skeletal muscle mass is associated with functional impairment and physical disability. Janssen I, Heymsfield SB, Ross R. Journal of the American Geriatrics Society (2002). https://pubmed.ncbi.nlm.nih.gov/12028177/
- Muscle mass index as a predictor of longevity in older adults. Srikanthan P, Karlamangla AS. The American Journal of Medicine (2014). https://doi.org/10.1016/j.amjmed.2014.02.007
How muscle mass influences blood sugar, metabolism, and aging
- Relative muscle mass is inversely associated with insulin resistance and prediabetes. Srikanthan P, Karlamangla AS. Journal of Clinical Endocrinology & Metabolism (2011). https://doi.org/10.1210/jc.2011-0435
- Sarcopenia: definition, epidemiology, and pathophysiology. Kim TN, Choi KM. Journal of Bone Metabolism (2013). https://doi.org/10.11005/jbm.2013.20.1.1

Protein quantity vs protein quality

Why minimum requirements don’t equal optimal muscle support
- The recommended dietary allowance of protein: a misunderstood concept. Wolfe RR, Miller SL. JAMA (2008). https://doi.org/10.1001/jama.299.24.2891
- The role of dietary protein in optimizing muscle mass, function, and health outcomes in older individuals. Wolfe RR. British Journal of Nutrition (2012). https://pubmed.ncbi.nlm.nih.gov/23107552/
Read our blog on What is protein quality?
Why essential amino acids and digestibility matter
- Protein content and amino acid composition of commercially available plant-based protein isolates. Gorissen SHM, Crombag JJR, Senden JMG, et al. Amino Acids (2018). https://doi.org/10.1007/s00726-018-2640-5
- Dietary protein quality evaluation in human nutrition. Food and Agriculture Organization (FAO). FAO Food and Nutrition Paper 92 (2013). https://www.fao.org/3/i3124e/i3124e.pdf
Why leucine plays a key role in activating muscle repair
- A high proportion of leucine is required for optimal stimulation of muscle protein synthesis in the elderly. Katsanos CS, Kobayashi H, Sheffield-Moore M, et al. American Journal of Physiology – Endocrinology and Metabolism (2006). https://doi.org/10.1152/ajpendo.00488.2005
- Leucine regulates translation initiation of protein synthesis in skeletal muscle after exercise. Norton LE, Layman DK. Journal of Nutrition (2006). https://doi.org/10.1093/jn/136.2.533S
- Leucine supplementation of a low-protein mixed macronutrient beverage enhances myofibrillar protein synthesis in young men. Churchward-Venne TA, Breen L, Di Donato DM, et al. American Journal of Clinical Nutrition (2014). https://doi.org/10.3945/ajcn.113.068775
Plant proteins are lower in leucine, so plant-based eaters need larger or combined servings to hit the ~3 g per-meal threshold — see Essential amino acids for women over 40 and high-protein vegan meals

Why protein distribution matters

How per-meal protein intake affects muscle protein synthesis
- Dietary protein distribution positively influences 24-h muscle protein synthesis in healthy adults. Mamerow MM, Mettler JA, English KL, et al. Journal of Nutrition (2014). https://doi.org/10.3945/jn.113.185280
- Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis. Areta JL, Burke LM, Ross ML, et al. Journal of Physiology (2013). https://doi.org/10.1113/jphysiol.2012.244897
How pre- and post-workout protein timing affects muscle protein synthesis
- Timing and distribution of protein ingestion during prolonged recovery from resistance exercise alters myofibrillar protein synthesis. Areta JL, Burke LM, Ross ML, et al. The Journal of Physiology (2013). https://pubmed.ncbi.nlm.nih.gov/23459753/
- Nutrient timing revisited: is there a post-exercise anabolic window? Aragon AA, Schoenfeld BJ. Journal of the International Society of Sports Nutrition (2013). https://pubmed.ncbi.nlm.nih.gov/23360586/
- (Optional swap if you want an even more “workout-window” focused paper)Is There a Postworkout Anabolic Window of Opportunity for Nutrient Consumption? Schoenfeld BJ, Aragon AA. Strength and Conditioning Journal (2018). https://pubmed.ncbi.nlm.nih.gov/30702982/
What intermittent fasting / time-restricted eating means for lean mass when lifting
- Effects of eight weeks of time-restricted feeding (16/8) on basal metabolism, maximal strength, body composition, inflammation, and cardiovascular risk factors in resistance-trained males. Moro T, Tinsley G, Bianco A, et al. Journal of Translational Medicine (2016). https://pubmed.ncbi.nlm.nih.gov/27737674/
- The Effects of Intermittent Fasting Combined with Resistance Training on Lean Body Mass: A Systematic Review of Human Studies. Keenan S, Cooke MB, Belski R. Nutrients (2020). https://pubmed.ncbi.nlm.nih.gov/32781538/
- Effects of intermittent fasting combined with resistance training on body composition: a systematic review and meta-analysis. Ashtary-Larky D, et al. (2021). https://pubmed.ncbi.nlm.nih.gov/33984329/

Women, Hormones & Muscle

Why muscle loss accelerates during midlife hormonal transition
- Role of menopausal transition and physical activity in loss of lean and muscle mass: A follow-up study in middle-aged Finnish women. Juppi HK, Sipilä S, Cronin NJ, et al. Journal of Clinical Medicine (2020). ttps://pubmed.ncbi.nlm.nih.gov/32456169/
- Muscle and bone mass in middle-aged women: role of menopausal status and physical activity.
  Sipilä S, Törmäkangas T, Sillanpää E, et al. Journal of Cachexia, Sarcopenia and Muscle (2020). https://pubmed.ncbi.nlm.nih.gov/32017473/
- Sarcopenia and muscle function during menopause and hormone-replacement therapy. Dionne IJ, Kinaman KA, Poehlman ET. Sports Medicine (2000). https://pubmed.ncbi.nlm.nih.gov/10936902/
Read our blog on Menopause Muscle Loss in Women Over 40: Science & Solutions
How estrogen influences muscle strength, repair, and regeneration
- Estradiol’s beneficial effect on murine muscle function is independent of muscle activity. Greising SM, Baltgalvis KA, Kosir AM, et al. Journal of Applied Physiology (2011). https://pubmed.ncbi.nlm.nih.gov/20966194/
- Skeletal muscle action of estrogen receptor α is critical for the maintenance of mitochondrial function and metabolic homeostasis in females. Ribas V, Drew BG, Zhou Z, et al. Science Translational Medicine (2016). https://pubmed.ncbi.nlm.nih.gov/27075628/
- Deletion of estrogen receptor α in skeletal muscle results in impaired contractile function in female mice. Collins BC, Laakkonen EK, Lowe DA, et al. Journal of Applied Physiology (2018). https://pubmed.ncbi.nlm.nih.gov/29345963/
Read our blog on Strength training for perimenopause
Why “one-size-fits-all” protein guidance fails women
- Protein Requirements of Pre-Menopausal Female Athletes: Systematic Literature Review. Mercer D, Convit L, Condo D, et al. Nutrients (2020). https://pubmed.ncbi.nlm.nih.gov/33207749/
- Dietary protein requirement of female adults >65 years determined by the indicator amino acid oxidation technique is higher than current recommendations. Rafii M, Chapman K, Owens J, et al. The Journal of Nutrition (2015). https://pubmed.ncbi.nlm.nih.gov/25320185/
- Changes in muscle mass and strength after menopause. Maltais ML, Desroches J, Dionne IJ. Current Opinion in Clinical Nutrition and Metabolic Care (2009). https://pubmed.ncbi.nlm.nih.gov/19949277/

The Science of Protein & Aging

Why protein needs change after 40

Sarcopenia

Anabolic resistance

Muscle: a longevity powerhouse

Strength and independence

Metabolic health

Protein quantity vs protein quality

Protein quantity myths

Amino acid composition

Leucine as a muscle-building signal

Why protein distribution matters

Timing and distribution of protein

Protein intake around workouts

Fasting & muscle

Women, Hormones & Muscle

Perimenopause, menopause, and muscle loss

Estrogen and muscle function

Protein strategy across female life stages