Why Protein Matters More Than Ever After 70

This is called anabolic resistance, and understanding it is critical to maintaining muscle, strength, and independence in advanced age.

Anabolic resistance is real

Anabolic resistance is the decreased ability of muscle tissue to respond to the anabolic signal of dietary amino acids and resistance exercise.¹ It's not that your muscles can't build protein. It's that they're less responsive to the signals that trigger protein synthesis.

This happens for several reasons. Mitochondrial function declines with age. Cellular signalling becomes less efficient. Insulin sensitivity decreases. The hormonal environment becomes less anabolic. All of these factors combine to create muscle tissue that's resistant to growth signals.

The consequence is that an older adult needs considerably more protein stimulation to achieve the same degree of muscle protein synthesis as a younger adult. What this means practically is that you can't eat the way you did at 40 and expect the same result.

A younger person might build muscle on 20 grams of protein at a meal. By your 70s, you might need 40 to 50 grams to trigger a similar response. The threshold has literally doubled or more.

Anabolic resistance means your muscles have become less responsive to protein. This isn't optional to address. It's the primary driver of sarcopenia. Feed the resistance.

Why elderly need more protein

This is where recommendations diverge from reality. Official dietary recommendations are still based on earlier science that didn't account for anabolic resistance. They suggest 0.8 grams of protein per kilogramme of body weight daily.

For someone over 70 trying to maintain muscle, this is woefully inadequate. Research shows that older adults maintaining muscle require between 1.2 and 2 grams per kilogramme daily, depending on activity level and how much muscle loss they're already experiencing.²

This isn't to pack on muscle. This is just to maintain what you have. Muscle is metabolically expensive to maintain. Your body would prefer to lose it and reduce the energy cost. Without adequate protein and stimulus to keep it, muscle is shed.

The higher protein intake serves multiple purposes. First, it provides the amino acids your muscles need to maintain protein synthesis despite anabolic resistance. Second, it provides amino acids for other functions including immune function, neurotransmitter synthesis, and hormonal balance. Third, higher protein intake is associated with improved satiety, so you eat more healthily overall.

Leucine is the critical trigger

Not all amino acids are equal. Leucine is the critical amino acid for triggering muscle protein synthesis. It's the one that signals the mTOR pathway, the primary driver of muscle protein synthesis.³

In younger people, roughly 20 to 25 grams of mixed protein provides enough leucine to trigger muscle protein synthesis.³ In older people, particularly those with significant anabolic resistance, 40 to 50 grams might be needed to get the same leucine threshold and the same protein synthesis response.

This is why spreading protein throughout the day matters. Three meals of 40 to 50 grams of protein each provides multiple opportunities to trigger muscle protein synthesis. A pattern of low protein at breakfast, low at lunch, and high at dinner doesn't work. You miss multiple opportunities throughout the day.

Leucine is found in all animal proteins. Beef, fish, eggs, and dairy all contain it. Plant proteins have less leucine per unit of protein, which is one reason why plant-based protein is less effective for maintaining muscle in older adults.

This doesn't mean you need to eat only animal protein. It means that animal proteins should be the foundation, with complementary plant foods providing fibre and other nutrients.

Complete amino acids matter

Complete amino acids means all nine essential amino acids in adequate ratios. Animal proteins are complete. Plant proteins are almost all incomplete, lacking one or more essential amino acids.

This matters for muscle protein synthesis. If the amino acid profile is incomplete, your body can't synthesise muscle protein at full efficiency. It's like trying to build a wall when you're missing certain types of bricks. Some amino acids are abundant, others are limiting.

Combining plant proteins to create a complete amino acid profile is possible (rice and beans, for example), but it requires knowledge and planning. Eating animal proteins provides complete amino acids automatically, with no planning required.

This is why, for people over 70 focused on muscle maintenance, animal proteins should form the foundation. They're complete, they're high in leucine, they're more bioavailable, and they provide multiple nutrients beyond just amino acids.

How much and how often

The target for someone over 70 concerned about muscle maintenance is 1.2 to 2 grams of protein per kilogramme of body weight daily. Distribute this across three to four meals.

For a 70-kilogramme person, this means 84 to 140 grams daily. Spread across three meals, that's 28 to 47 grams per meal. Most meals should be in the 35 to 50 gram range for optimal muscle protein synthesis stimulation.

Examples of single-meal protein sources reaching these targets.

• 3 eggs plus 100g meat: 40 grams protein
• 150g fish plus vegetables: 30-35 grams protein
• 100g liver with onions: 25 grams protein plus exceptional micronutrients
• 200g beef plus vegetables: 45 grams protein
• 150g yogurt plus nuts: 20-25 grams protein, less optimal than above
• Bone broth based soup with meat: 25-35 grams protein depending on preparation

The best sources after 70

Beef, particularly well-cooked cuts, provides complete protein, B vitamins, iron, zinc, and carnitine. It's satisfying and digestible when cooked properly.

Fish, particularly fattier varieties like mackerel and herring, provides complete protein plus omega-3 fats and vitamin D. Easy to prepare and digest.

Eggs, particularly from pastured hens, provide complete protein in a form that's incredibly bioavailable. The yolk provides choline and lutein. Include the yolk.

Dairy, particularly full-fat options, provides complete protein with calcium and fat-soluble vitamins. Cheese and yogurt are nutrient-dense options.

Organ meats, particularly liver, provide complete protein with exceptional micronutrient density. The protein is easily digestible. A small serving goes a long way.

Shellfish provide complete protein with unique minerals including zinc and selenium. Relatively easy to digest.

After 70, protein isn't optional. It's the primary tool for maintaining the muscle and strength that independence depends on. Build meals around it.

The bottom line

Anabolic resistance means your muscles need more protein to respond. This isn't a weakness. It's just physiology. Accept it, address it, and maintain muscle that supports independence.

Aim for 1.5 grams of protein per kilogramme of body weight daily, distributed across three meals of 35 to 50 grams each. Prioritise animal proteins for their complete amino acid profile and high leucine content. Pair protein with resistance exercise to provide the stimulus your muscles need.

The muscle you maintain in your 70s is the muscle that keeps you capable in your 80s. Feed it properly.

References

1. 1. Wall BT et al. Aging is accompanied by a blunted muscle protein synthetic response to protein ingestion. PLOS ONE, 2015. PMID 26506564.
2. 2. Bauer J et al. Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. JAMDA, 2013. PMID 23867520.
3. 3. Wolfson SA, Aragon AA et al. Leucine-Enriched Nutrients and the Regulation of mTOR Signalling and Human Skeletal Muscle Protein Synthesis. Current Opinion in Clinical Nutrition, 2008. PMID 18403916.