The Definitive Protein Tier List for Women Over 40: What to Eat for Maximum Results
Not all protein sources are created equal. Some deliver exceptional muscle-building benefits. Others barely move the needle. Here's the definitive ranking based on DIAAS scores, leucine content, and bioavailability - so you can prioritize the proteins that actually work.
Why Protein Quality Matters More After 40
When you're younger, your body is remarkably forgiving. You can eat lower-quality proteins and still maintain muscle.
After 40? Your body becomes selective. It needs higher-quality protein sources to trigger muscle protein synthesis effectively.
This isn't about eating MORE protein. It's about eating SMARTER protein.
The Ranking System
This tier list is based on three science-backed metrics:
- DIAAS Score: How much your body actually absorbs (FDA-recommended rating)
- Leucine Content: The "master switch" that triggers muscle building
- Bioavailability: How efficiently your body can use it
TIER 1: EXCELLENT (DIAAS > 1.0)
Your body uses MORE than 100% of the protein
Whey Protein Isolate - DIAAS: 1.09
Why it's top tier: Highest leucine content (11-14g per 100g), fastest absorption, complete amino acid profile. The gold standard for muscle preservation.
Best for: Post-workout, breakfast protein boost, quick meals
Serving example: 30g whey = ~33g usable protein
Milk & Greek Yogurt - DIAAS: 1.14
Why it's top tier: Highest DIAAS score of all proteins. Contains both fast (whey) and slow (casein) proteins. Complete nutrition package.
Best for: Breakfast, snacks, before bed
Serving example: 1 cup Greek yogurt = 20g protein, all highly usable
Whole Eggs - DIAAS: 1.13
Why it's top tier: Perfect amino acid ratio, high leucine (1.4g per 100g), includes healthy fats and choline. Nature's multivitamin.
Best for: Breakfast, any meal, incredibly versatile
Serving example: 3 eggs = 18g protein + nutrients
Beef - DIAAS: 1.11
Why it's top tier: High leucine (1.7g per 100g), complete amino acids, rich in iron and B vitamins. Excellent satiety.
Best for: Main meals, strength building
Serving example: 6 oz beef = 42g highly usable protein
Chicken - DIAAS: 1.08
Why it's top tier: Excellent leucine (2.1g per 100g), lean, affordable, versatile. The workhorse protein.
Best for: Daily protein staple, meal prep
Serving example: 6 oz chicken = 40g protein
Strategy: Get 60-70% of your daily protein from Tier 1 sources
TIER 2: VERY GOOD (DIAAS 0.90-1.0)
Soy Protein (Tofu, Tempeh, Edamame) - DIAAS: 0.90
Why it's very good: Highest plant protein quality. Complete amino acids. Good leucine for a plant source (2.7g per 100g).
Best for: Plant-based eaters, variety in diet
Serving example: 8 oz tofu = 20g protein, 90% usable
Fish & Seafood - DIAAS: ~1.10
Why it's very good: Complete proteins, omega-3s, highly digestible. Salmon, tuna, cod all excellent.
Best for: Heart health + muscle preservation
Serving example: 6 oz salmon = 40g protein + omega-3s
Strategy: Get 10-20% of your daily protein from Tier 2 sources
TIER 3: GOOD (DIAAS 0.80-0.89)
Pea Protein - DIAAS: 0.82
Why it's good: Popular plant protein, decent absorption. Works well blended with rice protein.
Limitation: Lower leucine than animal proteins
Serving example: 30g pea protein = ~25g usable protein
Quinoa - DIAAS: ~0.80
Why it's good: Complete plant protein, fiber, minerals. Rare for a grain.
Limitation: Lower protein concentration than animal sources
Serving example: 1 cup cooked quinoa = 8g protein
TIER 4: MODERATE (DIAAS 0.60-0.79)
Rice Protein - DIAAS: 0.59
Limitation: Your body only uses about 60% of it. Low leucine.
Better strategy: Combine with pea protein for better amino acid profile
Black Beans & Lentils - DIAAS: 0.54-0.60
Limitation: Incomplete amino acids, lower bioavailability, high fiber interferes with absorption
Better strategy: Excellent for overall health, but need larger amounts for muscle building
TIER 5: POOR (DIAAS < 0.60)
Wheat Protein - DIAAS: 0.40
Major limitation: Your body only uses 40% of it. Very low leucine. Incomplete amino acids.
Verdict: Don't rely on wheat protein for muscle preservation
Most Grains & Nuts - DIAAS: <0.50
Limitation: Great for overall nutrition, but poor for muscle building as primary protein sources
The 80/20 Strategy
For optimal muscle preservation after 40:
80% of protein from TIERS 1-2 (animal proteins, soy)
20% from TIERS 3-5 (variety, fiber, overall health)
Example Day (100g total protein):
Tier 1-2 (80g):
- Breakfast: 3 eggs (18g)
- Snack: Greek yogurt (20g)
- Lunch: 6 oz chicken (40g)
Tier 3-5 (20g):
- Side of quinoa (8g)
- Almonds snack (6g)
- Whole grains (6g)
Result: High-quality protein for muscle + variety for health
Why This Matters
Two women can both eat "100g protein per day" and get completely different results:
Woman A: Gets 80g from Tiers 1-2
→ Her body uses ~90g worth of protein
→ Muscles are well-maintained
Woman B: Gets 80g from Tiers 4-5
→ Her body uses ~50g worth of protein
→ Loses muscle despite "eating enough"
Same grams eaten. Completely different outcomes.
The Bottom Line
If you're losing muscle despite eating "enough protein," check your tiers.
Most women over 40 need to shift toward higher-tier sources.
You can actually eat LESS total protein and get BETTER results by choosing higher-quality sources.
Action Step:
This week, calculate what percentage of your protein comes from each tier. Aim to shift toward 80% from Tiers 1-2.
Quality over quantity. Always.
Sources: FAO Expert Consultation on Dietary Protein Quality Evaluation 2013; Nutrients 2023; American Journal of Clinical Nutrition 2020