Energy Balance: The Key to Managing Your Weight

Eating well isn’t just about what you consume—it’s also about how your body uses that energy. At its core, weight management is a simple equation: energy in versus energy out. But while the concept may sound straightforward, the reality is far more complex.

Everything we eat provides energy, measured in calories. Our bodies then burn this energy in multiple ways—by simply staying alive, digesting food, and powering movement. The goal of energy balance is to align what we eat with what we burn, helping us maintain, lose, or gain weight in a controlled and sustainable way.

To put this into practice, let’s break it down step by step.

Step 1: Track What You Eat

Before making any changes, it’s important to understand where you’re starting. A food diary is one of the simplest and most effective tools for building awareness of your eating habits. By recording what you eat, how much, and how it’s prepared, you gain a clearer picture of your daily energy intake.

While tracking every meal may seem tedious at first, it quickly becomes second nature. Over time, you’ll start recognizing patterns and portion sizes without needing to write everything down—giving you a practical, intuitive understanding of your own nutrition.

Step 2: Calculate Your Energy Intake

Once you’re aware of what you’re eating, the next step is understanding how much energy it provides. Nutrition labels on packaged foods make this easy—each label includes serving sizes, total calories, and the breakdown of macronutrients. For whole foods that don’t have labels, online databases like the USDA FoodData Central can help.

To calculate total daily energy intake, multiply the number of servings you eat by the calories per serving, and repeat for all foods consumed throughout the day. For example:

• Whole-wheat bread (1 slice): 100 calories
• Peanut butter (2 tbsp): 200 calories
• Strawberries (1 cup): 50 calories

Total meal calories = 350 calories

Repeating this process for each meal gives you an accurate picture of how much energy you’re consuming daily.

Step 3: Estimate Your Energy Output

Energy expenditure is more complicated to measure than energy intake, but we can estimate it based on three main factors:

Basal Metabolic Rate (BMR) – The energy required for essential functions like breathing, circulation, and cell repair. This makes up the majority of our daily calorie burn.

Thermic Effect of Food (TEF) – The energy used to digest, absorb, and metabolize food.

Physical Activity – Everything from walking to structured exercise. This is the most variable factor in daily energy burn.

To estimate your personal energy needs, start with BMR, which is determined by factors like age, weight, height, and muscle mass. The Mifflin-St Jeor Equation is a widely used method for this:

Women: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) - 161
Men: BMR = (10 × weight in kg) + (6.25 × height in cm) - (5 × age) + 5

For example, a woman weighing 55 kg, standing 172 cm tall, and aged 48 has a BMR of 1,224 calories per day—the baseline energy her body needs at rest.

To estimate Total Daily Energy Expenditure (TDEE), multiply BMR by an Activity Factor (AF) based on lifestyle:

• Sedentary (little or no exercise): BMR × 1.2
• Light activity (1–3 days of exercise per week): BMR × 1.375
• Moderate activity (3–5 days per week): BMR × 1.55
• Very active (6–7 days per week): BMR × 1.725
• Extremely active (intense exercise daily, physical job): BMR × 1.9

For the example above, if she exercises daily at a high intensity, her TDEE is:

1,224 × 1.725 = 2,111 calories per day

This means to maintain her weight, she needs to eat around 2,100 calories daily.

Step 4: Apply the Numbers to Your Goals

Once you know your daily energy intake and expenditure, you can adjust accordingly:

To maintain weight, match calorie intake to TDEE.
To lose weight, create a calorie deficit by eating less or increasing physical activity.
To gain weight, consume more than you burn, focusing on nutrient-dense foods.

A healthy, sustainable weight loss approach is a 250–500 calorie deficit per day, leading to a gradual ½–1 pound of weight loss per week. Similarly, a 250–500 calorie surplus supports steady, controlled weight gain.

Beyond weight management, tracking energy balance helps ensure your meals are nutrient-rich and satisfying—not just calorie-controlled. By aligning intake with your body’s needs, you create a balanced approach that supports long-term health.

Fueling Your Body for the Long Haul

Understanding energy balance is more than just counting calories—it’s about creating a sustainable approach to eating that supports both health and performance. By tracking food intake, estimating energy output, and making informed adjustments, you can maintain, lose, or gain weight in a way that works for you.

Ultimately, your body thrives when energy intake and expenditure are in sync. With this knowledge, you can fine-tune your nutrition to match your goals—fueling your body, maximizing performance, and feeling your best every day.

Dig Deeper

For a deeper look at how to calculate, interpret, and apply energy balance to your daily life, see Chapter 5: “Energy Balance” in Life in Every Bite: Exploring the Science of Healthy Eating: vegancurator.com/book