Macronutrients, Part 1: Why Protein Matters More Than You Think

When we talk about nutrition, we usually start with one question:

“What should I eat?”

To answer that well, it helps to understand the big building blocks of food — the macronutrients. There are three of them:

• Protein
• Carbohydrates
• Fat

They’re called “macros” because they’re the nutrients we need in the largest amounts.

Over the next few posts, we’ll break each one down in a practical, athlete-focused way. No fluff. No extremes. Just what actually helps you train, recover, and feel better.

We’re starting with the most important one for athletes:

Protein

Protein: The Foundation of the Human Body

Protein isn’t just “gym food” or something you only think about after a workout. It’s the structural and functional foundation of your body.

Unlike carbs and fats, which are mostly used for energy, protein is used to build, repair, and regulate nearly everything:

• Muscle tissue
• Bones and connective tissue
• Skin, hair, and nails
• Enzymes and hormones
• Immune cells
• Neurotransmitters that affect mood, focus, and sleep

If something in your body is doing work, protein is involved.

When you eat protein-rich foods, your body breaks them down into smaller units called amino acids. These amino acids are absorbed and then reassembled into exactly what your body needs in that moment — repairing muscle after training, rebuilding tissue, supporting immunity, or helping regulate digestion and hormones.

Amino Acids: The Real Building Blocks

Think of amino acids like LEGO pieces.

On their own, they’re small and simple. But when linked together in different sequences, they form thousands of unique proteins that do very different jobs in the body.

There are 20 amino acids used to build human proteins:

• 9 are essential, meaning you must get them from food
• Several others can become “conditionally essential” during hard training, illness, injury, or high stress

From these amino acids, the body creates tens of thousands of different proteins — some tiny, some massive. For example:

• Insulin is made from just 51 amino acids
• Titin, a muscle protein, contains over 34,000 amino acids

That’s the range we’re working with.

Why One Missing Amino Acid Matters

Here’s an important concept athletes often miss:

Your body can’t “half-build” proteins.

Protein synthesis depends on having all essential amino acids available at the same time. If even one is missing, the entire process slows down or stops.

A helpful analogy is a wooden barrel:

• Each plank represents an essential amino acid
• The barrel only holds water up to the height of the shortest plank

In other words, you’re only as good as your weakest link. If one amino acid is lacking, the rest can’t do their job — even if you’re eating plenty of calories overall.

Protein Deficiency: More Common Than You Think

Severe protein deficiency is rare in developed countries, but chronic under-eating of protein is extremely common — especially among:

• Active people
• Older adults
• People eating mostly plant-based
• Anyone training hard but eating “light”

This doesn’t show up as a dramatic illness. It shows up slowly.

Common signs of inadequate protein intake include:

• Constant soreness and poor recovery
• Fatigue and low energy
• Loss of strength or muscle over time
• Weak hair and nails
• More frequent illness
• Poor sleep or mood changes
• Increased injury risk

If you’re training consistently but not feeling like you’re adapting, protein is often the missing piece.

Protein Quality Matters

Not all protein sources are equal.

Animal-based proteins (meat, poultry, fish, eggs, dairy):

• Contain all essential amino acids
• Are highly digestible
• Are easier for the body to absorb and use

Most plant-based proteins:

• Are low in one or more essential amino acids
• Are harder to digest due to fiber and plant compounds
• Require careful combining to meet amino acid needs

This doesn’t mean plant foods are “bad.” It just means you have to be more intentional if you rely heavily on them.

Researchers use scoring systems to evaluate protein quality and usability. Without getting lost in the weeds, the takeaway is simple:

👉 Animal-based proteins consistently provide more usable protein per calorie than plant-based sources.

If your goal is recovery, performance, and long-term health, protein quality matters — not just total grams.

How Much Protein Do Athletes Need?

Your body is constantly breaking down and rebuilding tissue. There is no storage tank for amino acids, which means protein intake needs to be consistent and regular.

For athletes — especially those doing high-intensity training like CrossFit — protein needs are much higher than standard recommendations.

• Government RDA: ~0.8 g/kg (bare minimum to avoid deficiency)
• Active individuals: 1.6–2.2 g/kg per day

Protein needs may be even higher if you are:

• Training at high volume
• In a calorie deficit
• Over 40
• Trying to preserve or build lean mass

A simple, practical rule:

• Aim for at least 30 grams of protein per meal
• Spread intake across the day
• Include protein after training to support recovery

Consistency beats perfection here.

The Big Picture

Protein isn’t a shortcut or a supplement — it’s a requirement.

When protein intake is adequate:

• Recovery improves
• Strength is easier to maintain or build
• Energy is more stable
• Sleep and mood often improve
• Training feels more productive

When it’s not, everything else feels harder.

If you want a strong foundation for training, protein is where it starts.

Next up, we’ll break down fat — why it matters far more than most people think, and how under-eating it quietly sabotages performance.

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