As we pass the age of 40, protein must become more than something we think about just in terms of weight or fitness goals, it becomes foundational for healthy ageing, vitality, and quality of life.
In this blog post, I’ll explain:
- Why protein is so important as we age
- How our protein needs change
- How much protein women 40+ really need
- The best sources of protein and how to digest it properly
So, Why is protein so important as we age?
Protein supports muscle, and muscle = health.
After 40, it’s no longer just about “toning”. It’s about preserving the muscle we have and building more. Muscle impacts:
- Metabolic health and metabolism
- Mobility, strength, and bone density
- Blood sugar balance and immune function
All your organs and tissues are made of proteins, and your body is constantly repairing and rebuilding these. Without enough protein, your body prioritises essential organs only, and neglects your muscle tissue, which leads to faster muscle loss with age.
Protein and Amino Acids: The Building Blocks of Your Body
Protein is made up of 20 amino acids. They help:
- Build your body’s structure — muscles, bones, skin, and organs
- Support crucial functions — neurotransmitters, enzymes, detox pathways, hormone production
Prioritising high-quality, leucine-rich protein does more than protect muscle, it supports your metabolism, hormones, bones, blood sugar, and energy.
How Protein Needs Change After 40
From around age 30–35, we start to lose muscle mass at a rate of 3–8% per decade. This speeds up for women in perimenopause and menopause due to the decline in oestrogen, which normally helps preserve muscle.
This can lead to:
- Lower strength
- Increased body fat
- Less energy
The good news? You can reverse this trend, and protein is your best ally.
Muscle Protein Synthesis (MPS) and Leucine: The Secret to Building Muscle
Muscle growth happens through Muscle Protein Synthesis (MPS), which is triggered by:
- Strength/resistance training
- Consuming enough protein, especially leucine
After 40, we need more leucine per meal to get the same muscle-building effect as younger adults.
Aim for:
- 30–40g of high-quality protein per meal
- At least 2.5g of leucine per meal
This supports MPS and helps preserve and build lean muscle.
Why Your First Meal of the Day Matters
According to Dr. Donald Layman, getting an optimal dose of protein in your first meal is essential. MPS lasts about 1.5 to 2 hours, so spacing out protein evenly across three meals keeps you in a muscle-building state throughout the day.
Animal vs Plant Protein: What’s Best?
- Animal protein is more complete and bioavailable (better absorbed), especially for leucine.
- Examples: Chicken, beef, eggs, turkey, dairy, fish
- Examples: Chicken, beef, eggs, turkey, dairy, fish
- Plant protein can still help, but you’ll need 35–45% more to meet needs due to lower absorbability.
- Examples: Lentils, tempeh, beans, nuts, seeds
If you’re plant-based, consider combining proteins and using tools like protein powders to hit your goals.
Protein Powders: Helpful or Hype?
Whey protein isolate = excellent option (complete, rich in leucine)
Pea or hemp = useful but may require higher intake
Flavoured or artificial blends = best avoided
Collagen powders don’t count towards your daily protein goal, they lack leucine and don’t stimulate MPS.
How Much Protein Do Women Over 40 Really Need?
Forget the outdated RNI of 0.75g/kg. That’s just for deficiency prevention.
For healthy aging and muscle preservation, aim for:
- 1.2–1.6g per kg of body weight/day (minimum)
- 1.5–2.2g per kg/day for active women or those wanting to improve body composition
Easier Rule: Aim for 30–50g protein per meal, 3x per day.
Trouble Digesting Protein?
Protein digestion starts in the brain and mouth, not just the stomach!
Tips to support digestion:
- Eat in a relaxed state, take 3 deep breaths before meals
- Chew thoroughly (20–40 times per bite)
- Optimise stomach acid (especially if you’ve had H. pylori or long-term digestive issues)
Bloating, belching, or undigested food in stools? You may need to work on digestion first.
Signs You Might Not Be Digesting Protein Well
- Bloating after high-protein meals
- Undigested food in stool
- Fatigue, low strength, cravings despite high protein intake
- Low “Total Protein” on blood work (<69g/L)
The Bottom Line
If you’re a woman over 40, protein is non-negotiable.
It’s about more than body composition, it’s about:
- Staying strong, mobile, and independent
- Supporting your bones, metabolism, and blood sugar
- Preventing frailty, falls, and muscle loss
- Feeling more energised and balanced every day
Start with 30g per meal, focus on high-quality sources, and support digestion. Your future self will thank you!
Book a free discovery call here to explore working together or joining my Midlife Thrive membership.
And don’t forget to tune into the full episode on the podcast: Episode 46: Why Protein Matters More After 40
