Why do we need more nutrients when we are more active?

November 18, 2025 •

5 min read

According to the American College of Sports Medicine, physical activity, athletic performance, and recovery are all enhanced by optimal nutrition. It's a common misconception that simply eating more is enough, but active individuals need a greater quantity and specific type of nutrients to fuel their bodies and aid recovery.

Quick Summary

Increased physical activity raises energy demands, requiring more macronutrients like carbohydrates and protein for fuel and muscle repair. Fluid loss through sweat also necessitates increased hydration and electrolyte intake. Micronutrients, including vitamins and minerals, are crucial for supporting these metabolic processes and overall health.

Key Points

Increased Energy Demands: Active bodies require more calories to compensate for higher energy expenditure during and after exercise to prevent fatigue.
Fueling Muscles: Carbohydrates are the body's primary fuel source, and active individuals need to consume more to replenish depleted muscle and liver glycogen stores.
Muscle Repair and Growth: Protein intake needs increase significantly for active people to repair muscle tissue damaged during workouts and support muscle synthesis.
Essential Micronutrients: The body's demand for vitamins and minerals, such as iron, calcium, and B vitamins, rises to support metabolism, bone health, and oxygen transport.
Critical for Hydration: Increased sweat loss requires consuming more fluids and electrolytes to maintain hydration, regulate body temperature, and ensure optimal performance.
Strategic Timing: The timing of nutrient intake before, during, and after exercise is crucial for maximizing energy availability, enhancing recovery, and promoting adaptation.
Enhanced Recovery: Proper post-exercise nutrition, particularly combining carbohydrates and protein, is vital for rapid glycogen replenishment and tissue repair.

The Science of Increased Nutritional Needs

When you engage in physical activity, your body's energy expenditure increases dramatically. The extra calories burned need to be replaced to maintain energy balance. However, this isn't simply about consuming more food; it’s about providing the right nutrients to support the physiological changes that occur during and after exercise. This involves everything from fueling muscle contraction and repairing tissue to regulating body temperature and supporting immune function. Failing to meet these elevated needs can result in fatigue, poor performance, delayed recovery, and an increased risk of injury and illness.

How Macronutrients Fuel an Active Body

Macronutrients—carbohydrates, protein, and fat—form the foundation of energy for any active person. Each plays a distinct but critical role in optimizing performance.

Carbohydrates: This is your body's primary and most efficient source of fuel, especially during high-intensity exercise. They are broken down into glucose, which is either used immediately for energy or stored in the muscles and liver as glycogen. As activity levels increase, so does the demand for and depletion of glycogen stores. Consuming adequate carbohydrates is vital for sustained energy and performance, particularly during endurance activities lasting more than 60-90 minutes.
Protein: While carbohydrates are the main fuel, protein is essential for repairing and rebuilding muscle tissue that is stressed or damaged during exercise. It provides the amino acids necessary for muscle protein synthesis, a process critical for adaptation and growth. For active individuals, the recommended daily protein intake is higher than for sedentary people, often falling in the range of 1.2 to 2.0 grams per kilogram of body weight, depending on the intensity and duration of activity.
Fats: Dietary fats are a concentrated source of energy, particularly for lower-intensity, longer-duration activities where fat is used as a primary fuel source. They also play a crucial role in hormone production and the absorption of fat-soluble vitamins (A, D, E, and K). Athletes should focus on healthy fats from sources like nuts, seeds, and avocados, which provide sustained energy and support overall health.

The Importance of Micronutrients and Hydration

Beyond the major energy sources, physically active individuals also have a heightened need for micronutrients and fluids. Vitamins and minerals are essential co-factors in metabolic processes, while water is vital for thermoregulation and nutrient transport.

Vitamins: B-complex vitamins are crucial for energy metabolism, helping to convert food into usable energy. Antioxidant vitamins, like C and E, help protect the body from exercise-induced oxidative stress. Vitamin D is important for bone health and immune function.
Minerals: Iron is vital for transporting oxygen to working muscles, and a deficiency can lead to fatigue. Calcium is essential for bone strength and muscle contractions. Magnesium and potassium are both important electrolytes involved in muscle function and nerve signaling.
Hydration: Water is often referred to as the most important nutrient for athletes. Intense exercise and sweating lead to significant fluid loss, which if not replaced, can impair performance and lead to heat-related illnesses. Proper hydration helps regulate body temperature, transport nutrients, and maintain blood volume.

Comparison of Nutritional Needs: Active vs. Sedentary


Nutrient	Sedentary Individual	Active Individual (Moderate)	Active Individual (Endurance)
Energy (Calories)	Lower needs, based on basal metabolism	Increased needs to support daily activity and training	Significantly higher, often 3,000-5,000+ kcal/day
Carbohydrates	45-65% of total calories, general needs	5-7 g/kg/day, higher total intake	8-12 g/kg/day, for prolonged, intense activity
Protein	0.8-1.0 g/kg of body weight	1.0-1.2 g/kg of body weight	1.2-2.0 g/kg of body weight
Fat	20-35% of total calories	20-35% of total calories, similar percentage	20-35% of total calories, but higher total intake
Hydration	~2 liters/day, adjust for climate	Higher intake, replacing sweat loss during exercise	Higher and more strategic intake, includes electrolytes
Micronutrients	Met through a balanced diet	Higher requirements of certain vitamins/minerals like iron, calcium	Potentially higher requirements, may need supplementation

Tailoring Nutrition for Enhanced Performance

Developing a nutritional strategy is key for anyone with a regular exercise routine, from a casual gym-goer to a competitive athlete. The timing of nutrient intake can significantly impact recovery and performance.

Pre-Workout: Eating a meal or snack high in complex carbohydrates 1-2 hours before exercise ensures your body has adequate glycogen stores for energy. A smaller dose of simple carbohydrates might be suitable right before a short session, but complex carbs are better for sustained energy.
During Workout: For activities lasting over an hour, consuming easily digestible carbohydrates and electrolytes from a sports drink or gel can help maintain energy levels and delay fatigue. Regular fluid intake is also critical for staying hydrated.
Post-Workout: A combination of high-quality protein and carbohydrates is recommended within two hours after exercise to replenish glycogen stores and repair muscle tissue. A ratio of 4:1 carbohydrates to protein is often cited for optimal recovery.

The Role of the Increased Metabolic Rate

Exercise increases your body's metabolic rate, which is the rate at which it burns calories for energy. During intense physical activity, your body operates at a much higher metabolic rate than when at rest. This elevated rate continues even after the workout has finished, a phenomenon known as Excess Post-exercise Oxygen Consumption (EPOC). EPOC is the extra oxygen the body uses to return to its pre-exercise state, a process that requires additional calories and nutrients to fuel. This includes repairing damaged muscle fibers, restoring glycogen stores, and re-oxygenating blood. Therefore, the need for more nutrients is not just to power the workout itself but also to support the recovery and adaptation processes that occur long after the activity has ceased. Ignoring this increased demand can stall progress, leading to under-recovery and potential burnout.

Conclusion

In conclusion, the reason we need more nutrients when we are more active is rooted in the body's fundamental response to physical stress. Exercise depletes energy stores, breaks down muscle tissue, and causes fluid and electrolyte loss. To counteract these effects and support adaptation, the body requires an increased and strategically timed intake of macronutrients for fuel and repair, and micronutrients for metabolic support. Adopting a well-planned nutrition strategy that aligns with the intensity, duration, and type of activity is essential for enhancing performance, accelerating recovery, and promoting long-term health. Prioritizing nutrient-dense foods and adequate hydration is the most effective approach for anyone with an active lifestyle to achieve their fitness goals. While supplements can play a role, a "food first" philosophy remains the cornerstone of proper sports nutrition.

Visit the Better Health Channel for more detailed information on sport and exercise nutrition

Frequently Asked Questions

Active people need more calories to match their increased energy expenditure during physical activity. The body burns more calories to fuel muscle contraction, heart rate, and metabolism, and these must be replaced to maintain energy balance.

Both are crucial, but they serve different purposes. Carbohydrates are the body's primary energy source for exercise, while protein is essential for muscle repair and growth after a workout. A balanced intake of both is required for optimal performance and recovery.

Exercise increases body temperature, causing the body to sweat to cool down. This process results in significant fluid and electrolyte loss, which must be replenished to prevent dehydration, maintain performance, and regulate body temperature.

Strategic nutrient timing helps optimize energy levels and recovery. Consuming carbohydrates before and during prolonged exercise provides fuel, while a combination of carbs and protein after a workout speeds up glycogen replenishment and muscle repair.

For most active individuals, a well-planned diet rich in whole foods can provide all the necessary nutrients. Supplements are generally only needed if there is a specific deficiency or for highly intense, prolonged training, and should be considered with professional guidance.

Micronutrients like B vitamins assist with energy metabolism, while minerals like iron and calcium are important for oxygen transport, bone health, and muscle function. Antioxidant vitamins help combat exercise-induced oxidative stress.

If an active person doesn't consume enough nutrients, it can lead to negative consequences like fatigue, poor athletic performance, slower recovery, loss of muscle mass, and an increased risk of illness and injury.