You don't need a nutrition degree to coach well, but you do need working fluency in what protein, carbs, fats, and the key micronutrients actually do — enough to explain it simply and correctly, every time a client asks.
Clients ask nutrition questions constantly, often the same handful over and over. This lesson covers the core science behind the answers you'll give most — clearly enough to actually use in a real conversation, not just recite.
The Three Macronutrients
| Macronutrient | Calories/gram | Primary Role | Common Sources |
|---|---|---|---|
| Protein | 4 | Tissue repair, muscle growth, satiety | Meat, fish, eggs, dairy, legumes, tofu |
| Carbohydrates | 4 | Primary energy source, especially for training | Rice, oats, fruit, potatoes, whole grains |
| Fats | 9 | Hormone production, vitamin absorption, cell health | Oils, nuts, seeds, avocado, fatty fish |
Every general meal plan you'll build in Lesson 5 starts from these three — how much of each, based on the client's goal and preferences.
Why Protein Gets Special Attention
Protein comes up more than any other topic, for good reason: it supports muscle repair and growth, it's the most satiating macronutrient (helping clients feel fuller on fewer calories), and most people — especially anyone new to structured eating — genuinely under-eat it relative to their goals.
The Flex Cult's free protein calculator is a useful tool to point clients toward for a personalized starting estimate.
Key Micronutrients Clients Ask About
| Micronutrient | Primary Role | Common Sources |
|---|---|---|
| Iron | Oxygen transport in blood | Red meat, spinach, lentils, fortified cereals |
| Vitamin D | Bone health, immune function | Sunlight exposure, fatty fish, fortified milk |
| Calcium | Bone structure, muscle contraction | Dairy, leafy greens, fortified plant milks |
| Vitamin B12 | Nerve function, red blood cell formation | Meat, dairy, eggs (a common gap for vegans) |
| Magnesium | Muscle & nerve function, energy production | Nuts, seeds, leafy greens, whole grains |
| Omega-3 fatty acids | Anti-inflammatory support, heart & brain health | Fatty fish, walnuts, flaxseed, algae oil |
Match each nutrient to its primary function. Instant feedback after each answer.
Fiber & Water — The Overlooked Basics
- Fiber supports digestive health, feeds beneficial gut bacteria, and significantly improves satiety — most clients benefit from eating more of it, mainly through vegetables, fruit, legumes, and whole grains.
- Water affects energy, appetite regulation, and exercise performance. There's no single perfect number for everyone, but a simple, practical starting cue — drinking enough that urine is pale yellow — works well for most healthy clients.
With the core nutrition science in place, Lesson 4 covers the other half of the equation: energy balance, and how calories in versus calories out actually plays out with real clients.
- Protein and carbs provide 4 calories per gram, fat provides 9 — each with a distinct primary role in the body.
- A common general protein guidance range for active adults is 1.6-2.2g/kg bodyweight per day — general education, not a prescription.
- Iron, vitamin D, calcium, B12, magnesium, and omega-3s are the micronutrients clients ask about most — you can explain function and food sources, not diagnose or treat deficiencies.
- Fiber and water are simple, high-impact basics most clients under-prioritize.
- Complete the Macro Matching Game above until you score at least 7/8.
- Practice explaining protein's role in one sentence you could say to a client with zero nutrition background.
- Try the free protein calculator yourself to see how the numbers work in practice.