Introduction
After age 40, the body naturally starts losing muscle mass -- approximately 3-8% per decade (Cruz-Jentoft et al., 2019). This process, called sarcopenia, accelerates after 50. The good news is that adequate protein intake combined with regular resistance training can significantly slow this process and in some cases even reverse it.
Why Does the Body Need More Protein After 40?
Anabolic resistance
As we age, the body becomes less responsive to the anabolic (muscle-building) effect of protein (Wall et al., 2015). This means that the same amount of protein that triggered a strong muscle protein synthesis response at age 25 may not produce the same response at 50.
In practice, this means two things:
- You need more protein per meal to cross the muscle protein synthesis threshold
- The minimum leucine amount per meal is higher
The leucine threshold rises
In younger individuals, approximately 2-2.5g of leucine per meal triggers muscle protein synthesis. After 40, this threshold rises to approximately 3-4g per meal (Moore et al., 2015).
This is important knowledge because it affects which protein and how much you should consume at each meal.
Leucine content in different protein sources (30g serving):
- Whey isolate: ~3.5g leucine
- Whey concentrate: ~2.8g leucine
- Pea protein: ~2.4g leucine
- Casein: ~2.3g leucine
- Hemp protein: ~1.5g leucine
Therefore, whey isolate is the best choice for crossing the leucine threshold with a single serving.
How Much Protein After 40?
Recommended amounts for active older adults:
- General recommendation: 1.2-1.6g/kg body weight per day (Bauer et al., 2013)
- Active athlete over 40: 1.6-2.2g/kg body weight per day
- Sarcopenia risk reduction: At least 1.2g/kg body weight per day
For comparison: the standard dietary recommendation for adults is only 0.8g/kg, which may be insufficient for maintaining muscle mass after 40 (Volpi et al., 2013).
Protein contributes to the growth and maintenance of muscle mass. Protein also contributes to the maintenance of normal bones.
Distributing Protein Throughout the Day
One of the most important factors after 40 is even distribution of protein across meals. Why?
- Each meal needs to cross the leucine threshold (~3g)
- A large amount of protein at once does not compensate for other protein-poor meals
- Goal: 30-40g of protein 3-4 times per day
Sample day for a 70kg person (target: 120g protein):
Breakfast (30g protein): Protein shake with whey isolate (25g) + Greek yogurt (8g)
Lunch (35g protein): Fish or meat with vegetables
Snack (20g protein): Protein bar or nuts with Greek yogurt
Dinner (35g protein): Complete meal with chicken or turkey
Which Protein Is Best After 40?
Whey isolate: The best choice for crossing the leucine threshold. Fast absorption makes it ideal for morning and post-workout.
Casein or milk protein isolate: Excellent before bed. Slow digestion ensures amino acid availability throughout the night, which is especially important for maintaining muscle mass in older adults.
Collagen: While collagen is not a complete protein for muscle building, it supports joints, skin, and cartilage. A good addition to an older adult's daily routine, but not a replacement for protein powder.
Creatine: Though not a protein, creatine is especially beneficial after 40. It supports strength performance and may help maintain muscle mass.
Frequently Asked Questions
Is it possible to build muscle after 50? Yes, absolutely. With regular resistance training and adequate protein intake, building muscle is possible at any age. The process is slower than in your 20s, but results are still significant.
Do I need to use protein powder? Protein powder is a convenient way to ensure adequate intake, especially when getting enough from whole food alone is challenging. It is not mandatory but is a practical tool.
Do women need as much protein as men? Yes, relative to body weight, protein needs are similar. Women after menopause especially need to pay attention to protein intake, as hormonal changes accelerate muscle loss.
Is too much protein dangerous at an older age? In people with healthy kidneys, there is no evidence that recommended amounts (1.2-2.2g/kg) are dangerous. However, regular health check-ups are sensible.
Is resistance training safe after 40? Yes, resistance training is actually one of the most important activities after 40. Start gradually and consult a trainer if needed. Training combined with adequate protein is the best combination for maintaining muscle mass.
References
- Volpi E, Campbell WW, Dwyer JT, et al. (2013). Is the optimal level of protein intake for older adults greater than the recommended dietary allowance? The Journals of Gerontology Series A, 68(6), 677-681.
- Bauer J, Biolo G, Cederholm T, et al. (2013). Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. Journal of the American Medical Directors Association, 14(8), 542-559.
- Wall BT, Gorissen SH, Pennings B, et al. (2015). Aging is accompanied by a blunted muscle protein synthetic response to protein ingestion. PLOS ONE, 10(11), e0140903.
- Moore DR, Churchward-Venne TA, Witard O, et al. (2015). Protein ingestion to stimulate myofibrillar protein synthesis requires greater relative protein intakes in healthy older versus younger men. The Journals of Gerontology Series A, 70(1), 57-62.
- Cruz-Jentoft AJ, Bahat G, Bauer J, et al. (2019). Sarcopenia: revised European consensus on definition and diagnosis. Age and Ageing, 48(1), 16-31.
See also:
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Disclaimer
A food supplement is not a substitute for a varied and balanced diet and a healthy lifestyle.
