Evidence-Based Nutrition Guide for Fitness Goals: From a Qualified Nutritionist

# Evidence-Based Nutrition Guide for Fitness Goals

**By Kayla, Personal Trainer & University-Qualified Nutritionist** *Bachelor's Degree in Nutrition | Certificate III & IV in Fitness*

Introduction: Why Nutrition Makes or Breaks Your Results

As a university-qualified nutritionist and personal trainer, I've worked with hundreds of clients who train hard but struggle to see results. The common denominator? Nutrition.

This guide combines peer-reviewed nutrition science with practical application strategies I use daily with clients at Housed Fitness. Everything here is evidence-based, tested, and proven effective.

The Three Foundational Principles

1. Energy Balance is King

**The First Law of Thermodynamics** applies to fat loss and muscle gain:

**For Fat Loss:** Caloric deficit (consume less than you burn) **For Muscle Gain:** Caloric surplus (consume more than you burn) **For Maintenance:** Caloric balance

**How to Calculate Your Needs:**

**Step 1: Calculate BMR (Basal Metabolic Rate)**
Men: 10 × weight(kg) + 6.25 × height(cm) - 5 × age + 5
Women: 10 × weight(kg) + 6.25 × height(cm) - 5 × age - 161

**Step 2: Apply Activity Multiplier**
Sedentary (office job): BMR × 1.2
Light activity (exercise 1-3 days/week): BMR × 1.375
Moderate (exercise 3-5 days/week): BMR × 1.55
Very active (exercise 6-7 days/week): BMR × 1.725
Athlete (training 2x per day): BMR × 1.9

**Step 3: Adjust for Goals**
Fat loss: -300 to -500 calories
Muscle gain: +200 to +400 calories
Maintenance: No adjustment

2. Protein is Your Priority

**The Science:**
Research consistently shows protein is the most important macronutrient for body composition. It:
Preserves muscle during fat loss
Builds muscle during surplus
Increases satiety (fullness)
Has highest thermic effect (burns calories digesting it)

**Optimal Intake (Evidence-Based):**

**For Fat Loss:** 2.0-2.4g/kg bodyweight **For Muscle Gain:** 1.6-2.2g/kg bodyweight **For Maintenance:** 1.6-1.8g/kg bodyweight

**Example:** 70kg person aiming for muscle gain
Target: 70kg × 2.0g = 140g protein daily
Spread across 4-5 meals = 28-35g per meal

**High-Quality Protein Sources:**
Chicken breast: 31g per 100g
Greek yogurt: 10g per 100g
Eggs: 6g per egg
Salmon: 25g per 100g
Whey protein: 24g per 30g scoop
Lentils: 9g per 100g

3. Timing Matters (But Less Than You Think)

**What the Research Actually Shows:**

**Protein Timing:**
Total daily protein > timing
Post-workout window is 24-48 hours (not 30 minutes!)
Distribute evenly across meals for optimal muscle protein synthesis

**Carbohydrate Timing:**
Pre-workout: 1-2 hours before for energy
Post-workout: Within 2 hours for glycogen replenishment
More important for athletes training 2+ times daily

Goal-Specific Nutrition Strategies

Goal 1: Fat Loss While Preserving Muscle

**The Challenge:** Losing fat without losing hard-earned muscle requires precision nutrition.

**My Evidence-Based Protocol:**

**Caloric Deficit:** 300-500 calories below maintenance

**Macronutrient Split:**
Protein: 2.0-2.4g/kg (40% of calories)
Carbs: 2.0-3.0g/kg (30% of calories)
Fats: 0.8-1.2g/kg (30% of calories)

**Sample Day (70kg person, 1800 calories):**

**Breakfast (400 cal):**
3 eggs scrambled
1 cup spinach
1 slice whole grain toast
½ avocado

**Mid-Morning Snack (200 cal):**
Greek yogurt (170g)
Handful of berries

**Lunch (500 cal):**
Grilled chicken breast (150g)
Quinoa (1 cup cooked)
Mixed vegetables
Olive oil dressing

**Pre-Workout (150 cal):**
Banana
10g almonds

**Post-Workout (300 cal):**
Protein shake (whey + water)
Apple

**Dinner (450 cal):**
Salmon (120g)
Sweet potato (150g)
Broccoli and carrots
Lemon and herbs

**Total Macros:**
Protein: 165g (37%)
Carbs: 135g (30%)
Fat: 65g (33%)

**Key Fat Loss Strategies:** 1. **Meal frequency:** 4-5 meals for satiety 2. **Fiber target:** 25-35g daily (keeps you full) 3. **Hydration:** 35-40ml/kg bodyweight 4. **Sleep:** 7-9 hours (affects hunger hormones) 5. **Refeeds:** One higher carb day per week (prevents adaptation)

Goal 2: Muscle Gain (Lean Bulking)

**The Challenge:** Building muscle without excess fat gain requires a moderate surplus with optimal macros.

**My Evidence-Based Protocol:**

**Caloric Surplus:** 200-400 calories above maintenance

**Macronutrient Split:**
Protein: 1.8-2.2g/kg (30% of calories)
Carbs: 4.0-6.0g/kg (45% of calories)
Fats: 0.8-1.2g/kg (25% of calories)

**Sample Day (70kg person, 2800 calories):**

**Breakfast (550 cal):**
Oatmeal (80g dry)
Protein powder (30g)
Banana
Peanut butter (20g)
Cinnamon

**Mid-Morning Snack (350 cal):**
Greek yogurt (200g)
Granola (40g)
Honey drizzle

**Lunch (700 cal):**
Lean beef (150g)
Brown rice (200g cooked)
Mixed vegetables
Olive oil

**Pre-Workout (300 cal):**
White rice (150g cooked)
Chicken breast (100g)

**Post-Workout (400 cal):**
Protein shake (whey + milk)
2 rice cakes
Jam

**Dinner (500 cal):**
Salmon (150g)
Sweet potato (200g)
Asparagus
Butter

**Total Macros:**
Protein: 210g (30%)
Carbs: 315g (45%)
Fat: 78g (25%)

**Key Muscle Building Strategies:** 1. **Consistency:** Eat above maintenance daily 2. **Protein distribution:** 30-40g per meal, 4-5 times daily 3. **Training proximity nutrition:** Carbs before and after training 4. **Progressive overload:** Increase calories as weight increases 5. **Patience:** Aim for 0.25-0.5kg weight gain per week

Goal 3: Performance and Endurance

**For HYROX, CrossFit, Endurance Athletes**

**Macronutrient Split:**
Protein: 1.6-1.8g/kg
Carbs: 5.0-8.0g/kg (primary fuel source)
Fats: 1.0-1.5g/kg

**Intra-Workout Nutrition (for sessions >90 minutes):**
30-60g carbs per hour (energy gels, sports drinks)
Electrolytes (sodium, potassium, magnesium)
Hydration: 500-1000ml per hour

Supplements: What Actually Works

**My Evidence-Based Supplement Hierarchy:**

**Tier 1 Strong Evidence:**
1. **Protein Powder** Convenient way to hit protein targets
2. **Creatine Monohydrate** 5g daily, improves strength and power
3. **Caffeine** 3-6mg/kg, 30-60 minutes pre-workout

**Tier 2 Moderate Evidence:**
4. **Omega-3 (Fish Oil)** 2-3g daily, anti-inflammatory
5. **Vitamin D** If deficient (get blood test)
6. **Magnesium** If deficient, aids recovery and sleep

**Tier 3 Weak/Mixed Evidence:**
7. Beta-Alanine, Citrulline Malate, BCAAs

**Not Recommended:**
Fat burners (waste of money)
Testosterone boosters (ineffective for natural levels)
Most "proprietary blends"

Common Nutrition Mistakes

Mistake 1: Extreme Caloric Deficits

**The Problem:** -1000 calorie deficits crash metabolism and cause muscle loss

**The Solution:** Moderate deficits (-300 to -500 cal) with high protein

Mistake 2: Fearing Carbohydrates

**The Problem:** Low-carb when training hard = poor performance + muscle loss

**The Solution:** Match carbs to training intensity and volume

Mistake 3: Neglecting Meal Prep

**The Problem:** "Winging it" leads to poor choices and inconsistency

**The Solution:** Prep 2-3 days of meals every Sunday and Wednesday

Mistake 4: All-or-Nothing Mentality

**The Problem:** One "bad" meal derails entire week

**The Solution:** 80/20 rule 80% whole foods, 20% flexibility

My Personal Approach

As both a nutritionist and trainer, I practice what I preach:

**My Daily Habits:**
Track macros 6 days/week (one intuitive eating day)
Meal prep twice weekly
Protein at every meal
3L water daily
Flexible dieting approach (include foods I enjoy)

**At Housed Fitness,** I offer personalized nutrition consultations separate from training. This allows us to:
Analyze your current diet
Calculate your specific needs
Create customized meal plans
Provide ongoing accountability

Your 4-Week Action Plan

**Week 1: Awareness**
Track everything you eat (MyFitnessPal or similar)
Calculate your maintenance calories
Identify current protein intake

**Week 2: Structure**
Set macronutrient targets based on goals
Plan 3 days of meals
Start protein supplementation if needed

**Week 3: Consistency**
Hit macro targets 5/7 days
Meal prep routine established
Track weight and measurements

**Week 4: Refinement**
Adjust calories based on progress
Fine-tune meal timing
Implement pre/post-workout nutrition

Conclusion: Nutrition is a Skill

Just like strength training, nutrition takes practice. Be patient with yourself, stay consistent, and trust the process. The science works when you apply it consistently.

Remember: There's no "perfect" diet only the one you can sustain while reaching your goals.

---

**About the Author:** Kayla is a Personal Trainer (Cert III & IV Fitness) and university-qualified Nutritionist (Bachelor's Degree in Nutrition) based at Housed Fitness Macquarie Park. She specializes in evidence-based nutrition programming, lifestyle coaching, and helping individuals achieve sustainable fitness results through proper training and nutrition.

*Disclaimer: This article provides general nutritional information based on scientific research. Individual nutritional needs vary. Consult with a qualified nutritionist or dietitian for personalized nutrition advice, especially if you have medical conditions, food allergies, or specific dietary requirements.*