Protein After 40: What You Need to Know for Building and Keeping Muscle

Why Protein Matters After 40

If you’re getting back into fitness after 40, trying to change your body composition, or losing weight while trying to keep muscle, protein is worth paying attention to.

You may not need a protein powder. But getting enough protein each day can make it easier to support muscle growth, recovery, and healthy aging.

The Approach To Protein

Make Protein Part of Your Daily Plan

After 40, maintaining and building muscle becomes an important part of a fitness restart. Start by including a quality protein source with your meals. Protein powder can be useful when food alone makes it difficult to meet your needs, but it shouldn’t replace a balanced diet.

For people doing resistance training, research shows that adequate protein can help support increases in muscle mass and strength. Protein supplementation and resistance training

Simple approach:
Protein at breakfast + lunch + dinner, with a shake or protein-rich snack when needed.

Think About Muscle, Not Just Weight

If your goal is to change body composition, the number on the scale isn’t the whole story. You want to lose excess body fat while maintaining or building muscle. That’s especially important when weight loss is occurring with reduced appetite.

For people using GLP-1 medications, maintaining muscle deserves particular attention. Recent research found that a meaningful portion of weight lost during incretin-based treatment can be lean mass. Resistance training and adequate protein can be important parts of a muscle-preserving strategy. Scientific evidence — GLP-1 medications and lean mass

For women, particularly around and after menopause, muscle and bone health are also important considerations. Resistance training and adequate nutrition—including protein—are part of the bigger picture. Scientific evidence — Whey protein and postmenopausal women

Choose Protein That Fits

Whey vs. Plant Protein: What Should You Look For?

Both whey and plant proteins can help you meet your daily protein needs. You don’t need the “best” protein powder. The right choice depends on your diet, preferences, and how well you tolerate the product.

Whey protein

• Milk-based and generally a complete protein
• Naturally rich in essential amino acids, including leucine
• Generally highly digestible
• Whey isolate typically contains less lactose than whey concentrate

Plant protein

• Common sources include pea, soy, rice, and plant blends
• A good option if you avoid dairy or prefer plant-based nutrition
• Protein quality and digestibility vary by source
• Blends can combine different plant proteins to provide a broader amino-acid profile

Research shows that protein quality, amino-acid content, and digestibility can vary between protein sources. (Scientific evidence — The quality of plant and animal sourced proteins)

What to Compare on the Label

When choosing a protein powder, look beyond the protein number:

• Protein per serving — How much are you actually getting?
• Calories — Especially important if changing body composition.
• Ingredients — Check sugars, sweeteners, and other added ingredients.
• Digestibility — Choose a product your body tolerates well.
• Protein source — Whey, plant, or another option?
• Cost per serving — Compare value, not just the price of the container.
• Taste and convenience — You’ll get more value from a product you actually enjoy using.

The goal isn’t to find the “best” protein powder. It’s to find one that fits your nutritional needs and your routine.

Summary & Next Steps

If you’re restarting fitness after 40, start with the basics:

1. Strength train consistently.
   Give your muscles a reason to grow and adapt.
2. Make protein a regular part of your diet.
   Use food first, and consider protein powder when convenience helps
3. Look beyond the scale.
   Pay attention to strength, body composition, energy, and how you feel.
4. Choose products based on your needs—not hype.

Want to compare protein options?

Visit the Strength Restart Nutrition & Supplements page for our protein product comparisons, including protein source, amount, key features, pros, and cons.

It’s never too late to get stronger.

About the Author: Stan Ferrell, R.Ph., MS, is a pharmacist and fitness enthusiast who successfully restarted his own strength journey after 40. He specializes in helping adults navigate training, nutrition, and gear with a focus on longevity and safety.

This article is for educational purposes only and is not medical or individualized nutrition advice. Protein needs vary by individual. If you have a medical condition, take medications, or are using a GLP-1 medication, discuss your nutrition and protein needs with your healthcare professional or registered dietitian. Health and Fitness Disclaimer