The Ultimate Guide to Nutrition for Fitness and Performance
Nutrition is the most important piece of the fitness and health puzzle. Without proper nutrition, you’ll fail to reach your goals—it’s as simple as that. It doesn’t matter if you run or lift every day and nail your recovery; if your not fueling and refueling your body with the right energy, you won’t see any results.
Unfortunately, there’s so much conflicting information available online that can pull you in opposing directions if you let it. It’s great that the information is free and easily accessible, but when one source is telling you to fast for 3 days and the other says only eat meat, which way do you turn?
In this article, I’ll uncover the principles for success in nutrition, regardless of your fitness experience and goals.
The Building Blocks of Nutrition
To build a solid foundation in nutrition, you need to understand the macronutrients that fuel and sustain the body. Everything you consume falls into one of these three categories:
Carbohydrates
Fat
Protein
Each plays an important role in energy production, metabolism, and overall health.
Carbohydrates
Carbohydrates are the body’s primary energy source. They can be classified into three main types:
Monosaccharide - The simplest form, consisting of a single sugar molecule (e.g., glucose, fructose).
Oligosaccharide - Short chain of monosaccharides linked together.
Polysaccharide - Complex carbohydrates made up of long chains of sugar molecules (e.g., starch, glycogen).
Regardless of the type, all carbohydrates are eventually broken down into glucose, which is transported through the bloodstream to fuel cells throughout the body.
Food Sources:
Pasta
Fruit
Vegetables
Fats
Fats are the most energy-dense macronutrient and serve as the primary fuel source during prolonged, low-intensity exercise (e.g., walking). The body’s fat stores far exceed its carbohydrate reserves.
Before fats can be used for energy, they must be broken down from their storage form—triglycerides—into their basic components: glycerol and free fatty acids (FFAs). Only FFAs can be used to generate ATP, the body’s primary energy source.
Targeted marketing will make you believe that fat is bad, but that’s just not true. Fat is an essential part of your diet.
Healthy Fat Sources:
Nuts
Avocado
Red Meat
Proteins
Protein is essential for the growth, repair, and maintenance of all body tissues. While not a primary energy source, protein can contribute to fuel in certain conditions:
If carbohydrate stores are depleted, protein can be converted into glucose via gluconeogenesis.
In extreme cases, such as starvation, protein can also be converted into fatty acids for energy through lipogenesis.
During prolonged exercise, protein may supply up to 10% of the body’s energy needs.
Protein Sources:
Meat
Soya
Beans
General Macronutrient Distribution
Incorporating macronutrient recommendations into your diet can help you achieve specific health and fitness goals. Below are general guidelines for daily macronutrient distribution, along with adjustments tailored to various goals.
Carbohydrates: 45-65% of total daily calories
Fats: 20-35% of total daily calories
Proteins: 10-35% of total daily calories
These ranges are based on the Acceptable Macronutrient Distribution Ranges (AMDR) established by the Institute of Medicine.
Macronutrient Distribution Based On Your Goal
Weight Loss
Protein: Aim for the higher end of the AMDR (approximately 20-30% of total daily calories) to promote satiety and preserve lean muscle mass during caloric deficits.
Carbohydrates and Fats: Adjust intake within the general ranges to maintain a caloric deficit, focusing on complex carbohydrates and healthy fats.
Muscle Gain
Protein: Consume around 1.5-2 grams of protein per kilogram of bodyweight daily to support muscle synthesis.
Carbohydrates: Ensure adequate intake to fuel workouts and replenish glycogen stores, typically around 45-65% of total daily calories.
Fats: Maintain within the 20-35% range to support hormone production and overall health.
Endurance Training
Carbohydrates: Emphasise higher carbohydrate intake (closer to 65% of total daily calories) to provide sustained energy for prolonged activities.
Protein: Maintain adequate protein intake (approximately 1.2-1.4 grams per kilogram of body weight) to support muscle repair.
Fats: Keep within the general 20-35% range to meet energy needs without compromising performance.
Individual Recommendations
Macronutrient needs can vary based on factors such as age, sex, activity level, and health conditions. Tools like the DRI Calculator for Healthcare Professionals can provide personalised recommendations.
Consulting with a registered dietitian or nutritionist is advisable to tailor macronutrient intake to your individual goals and health status.
The Key Principles for Good Nutrition
1. If you want to lose weight, consume less calories than you burn
Weight loss isn’t complicated, it comes down to energy balance—calories in versus calories out. If you only remember one thing from this article, let it be this: THERE IS NO SUCH THING AS “WEIGHT LOSS” FOOD.
If you consistently consume fewer calories than your body burns, you will lose weight. However, the source of these calories matter too. A diet focused on whole, nutrient-dense foods will help you maintain muscle mass, energy levels, and overall health during a calorie deficit.
2. Track Calories (And Macronutrients)
You can’t manage what you don’t measure. Tracking your calorie and macronutrient intake can give you a clear understanding of how your diet aligns with your goals. Apps like MyFitnessPal, or a simple food diary can help you stay on track.
For muscle gain, tracking ensures you’re getting enough protein and total calories to support growth. For weight loss, it helps you maintain a caloric deficit while ensuring you’re getting enough nutrients.
3. Set Clear Goals (And Build Systems)
Without a clear goal, it’s easy to fall into inconsistent eating habits. Whether you’re trying to lose fat, build muscle, or improve endurance, your diet should align with your objectives. Define what success looks like and adjust your macronutrient intake accordingly.
You’ll struggle to reach your goals without the right systems in place to help you achieve them. You won’t achieve your goals from one effort, it is consistently performing habits that take you to success.
4. Be Good, Most of The Time
Rigid diets often lead to burnout. Instead of aiming for perfection, aim for consistency. Following a 80/20 approach—where 80% of your intake is made up of whole, nutrient dense foods, and 20% allows for flexibility—can help you stay on track without feeling deprived of your favourite foods.
5. Ignore the Fad Diets
From 3-day fasts to zero-carb diets, we all know someone who has said they were going to commit to an extreme diet only to quit a few weeks or days later.
Most fad diets works by simply creating a calorie deficit—but they often do so in an unsustainable way. Instead of chasing the latest trends, focus on balanced nutrition that you can maintain long-term.
Tips for Better Nutrition
1. Avoid Empty Calories
Not all calories are created equal. Highly processed foods, sugary drinks, and alcohol often contain “empty calories”—meaning they provide energy but lack essential nutrients. Prioritise whole foods that provide vitamins, minerals, fibre, and protein.
Examples of empty calories include:
Sugary drinks
Fast food
Processed snacks (crisps, sweets, pastries)
Alcohol
2. Make it easier to make good choices
Your weekly food shop has more of a bearing on the success of your diet than you might think. If you make bad decisions when you’re wheeling a trolley around the supermarket, you’re setting yourself up for failure for the rest of the week.
If your kitchen is stocked with nutritious, whole foods, you’re more likely to make good choices throughout the week. Plan meals ahead, create a shopping list, and avoid impulse purchases.
Simple strategies include:
Shop with a list to avoid buying junk food
Shop after eating a big meal
Prepare meals in advance so you don’t reach for convenience foods
Keep healthy snacks available nearby
Remember The Only Opinion That Matters
You are the master of your life. No one can tell you what you should eat, only you can make that decision. Your nutritional choices should be based on your goals, preferences, and what makes you feel good—not on external opinions.
Want Guidance? Here’s How I Can Help
Struggling to build a nutrition plan that fits your goals? I can help. I specialise in simplifying complex nutrition and fitness topics so you can take action with confidence.
Get personalised guidance on macronutrient intake and diet strategies
Learn how to build sustainable habits that align with your goals
Understand how nutrition fits into your training and lifestyle
Get in touch via HanscombePerformance.com or connect with me on LinkedIn.
