Why You’re Always Tired: Undereating is an Issue
Low caloric intake can significantly hinder a young athlete’s growth, development, and energy levels. I see this all too often with my clients and have personally experienced the effects of not eating enough during my playing career.
I want to break down what happens to performance when caloric intake is too low versus when an athlete is properly fueled. I’ll also share macronutrient guidelines and food selections to help athletes meet their daily energy needs and perform at their best.
Caloric Demands & Athletic Development
Even at rest, the body burns energy to maintain essential functions like breathing, cell production, and circulation. This energy expenditure is known as the basal metabolic rate (BMR) and it varies by individual.
For growing athletes, BMR can be 10-20% higher than an adult due to the additional energy demands of puberty. Building new tissue and bones, managing rapid cell turnover, and regulating hormonal changes require substantial fuel.
When you add training, practice, and the cognitive load of sport into the equation, total daily energy expenditure (TDEE) increases significantly. Depending on an athlete's size, their BMR typically ranges from 1,400-1,800 kcal per day. Daily movement outside of practice burns roughly 500 kcal, while sport activity can add another 700-1,500 kcal, bringing TDEE to 2,600-3,800 kcal per day.
Smaller athletes (100-120 lbs) fall on the lower end of that range.
Larger athletes (160-180 lbs) are at the higher end and beyond.
When food intake doesn't meet activity demands, the body is forced to function in a caloric deficit, leading to:
Lower strength levels and faster muscle fatigue
Decreased power output and reaction times
Slower recovery and increased muscle soreness
Higher risk of injury
Increased stress and inflammation
Stunted growth
If we want to avoid these negative outcomes, fueling properly has to be a priority. Skipping breakfast, eating a mediocre lunch, and having just one solid meal at dinner won’t cut it if the goal is improved performance.
What Fueling Properly Looks Like: The Macros
Fueling properly means getting the right balance of carbohydrates, protein, and fats. Here’s what each macronutrient does and how much an athlete needs.
Carbohydrates
Carbs are an athlete’s primary fuel source. They are broken down and stored as glycogen in the muscles and liver to be used during training and gameplay. Maintaining full glycogen stores through adequate daily carb intake is essential.
A general guideline is 3-4.5g of carbs per pound of body weight per day.
To optimize performance:
Hit daily carb targets consistently.
Consume a carb-rich meal 3-4 hours before activity to ensure energy availability.
Have quick-digesting carbs an hour before game time for readily available glucose to fuel the brain and nervous system.
Examples of carb-rich foods:
Oatmeal (1/2 cup) ~27g
Bagel ~50g
Yogurt (plain 6oz.) ~12g / (flavored 6oz.) ~30+
Bananas ~27g
Granola (1 cup) ~45g
Pasta (1 cup) ~40g
Sweet/white potatoes (medium potato) ~32g
White rice (1 cup) ~45g
Protein
It’s no secret that protein is vital for developing athletes, but how much is a good amount?
In general, it’s a safe bet to shoot for 1g per pound of bodyweight each day. While this isn’t always easy to hit, aiming for it ensures better development than not having a target at all.
This protein intake supports muscle growth, fuels activity, and aids recovery. Even on lighter training days, the goal should remain 1g/lb.
Examples of quality protein sources:
Chicken thighs (3.5oz) ~26g
Chicken breasts (3.5oz) ~31g
Ground beef (3.5oz) ~27g
Steak (3.5oz) ~31g
Eggs (1 large egg) ~7g
Salmon (3.5oz) ~25g
Greek Yogurt (6oz) ~17
Tofu (3.5oz) ~17g
Black beans (1/2 cup) ~8g
To read more on the benefits of protein, Coach Aurora has a great piece you can read here.
Fat
We are now in an era where we understand just how beneficial fat is for performance. The body uses this macronutrient as a fuel source during prolonged activity. Having adequate amounts stored in the body is essential for optimal performance.
A general guideline is 0.3-0.6g of fat per pound of body weight per day.
For a 160-lb athlete, this equates to ~65g of fat per day.
I know many young athletes focus on having low body fat and visible abs, but for peak performance, maintaining 12-15% body fat is actually ideal.
Examples of good sources of fat
Avocados (1/2 avocado) ~15g
Olive oil (1 tbsp) ~14g
Peanut butter (2 tbsp) ~16g
Almonds (1oz) ~14g
Cashews (1oz) ~12g
Flaxseeds (2oz) ~9g
Eggs (1 large egg) ~5g
Every athlete’s needs will differ slightly depending on factors like metabolism, sport, and training load. These guidelines serve as a starting point.
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Supplement Recommendations
The supplement industry is overwhelming, but my recommendations are simple.
Whey Protein (or plant-based protein if necessary): Helps meet daily protein needs without replacing whole foods.
Creatine Monohydrate: 5g daily for strength, power, and recovery. I’ll be writing a full article on this soon.
Magnesium Glycinate: 400-500mg before bed for recovery and sleep.
Fish Oil: 1,000-1,500 mg EPA + DHA daily for inflammation control and cognitive function.
These should be taken daily, even on rest days.
Wrapping Things Up
Too many youth athletes are undereating, leading to a caloric deficit that limits their potential. To maximize performance, recovery, and long-term development, focus on meeting daily caloric needs with balanced meals and proper fueling strategies.
Follow these guidelines consistently, and you'll see the benefits of proper nutrition in your energy levels, strength, and overall performance.
