Understanding Energy Balance
What Is Energy Balance?
You’ve likely heard the phrase “calories in, calories out.” This saying is a simplified way of explaining energy balance.
Calories In: Calories consumed from food and drinks.
Calories Out: Calories burned through physical activity, digestion, and basic body functions.
Generally, how these two balance out determines whether your body weight goes up, down, or stays stable:
Equal In and Out → Weight maintenance
More In than Out → Weight gain
More Out than In → Weight loss
How We Expend Energy
Throughout the day, you use energy for everything from physical activity to simply keeping your body alive and functioning. The total amount of calories you burn each day is called your total daily energy expenditure (TDEE).
There are three main ways we expend energy:
Basal Metabolic Rate (BMR)
Accounts for 60–70% of daily energy usage.
Covers essential bodily functions like breathing, circulation, and organ function.
Thermic Effect of Food (TEF)
About 8–10% of daily energy usage.
The energy required to digest, absorb, and metabolize food.
Activity Thermogenesis
Calories burned through movement, anything from walking to weight lifting.
Factors That Influence Energy Balance
Metabolism Is Adaptive
Your body adjusts to changes in diet and activity. For example, when you lose weight, your metabolic rate often slows down, making weight loss more challenging. This is called metabolic adaptation. .
Not All Calories Are Absorbed Equally
A slice of pizza versus a fruit and protein smoothie may both contain ~180 calories, but your body processes them differently:
Pizza: Highly digestible, low in fiber, and has little satiety.
Protein Smoothie: Takes longer to digest, high in fiber, and protein keeps you fuller longer.
Calories Influence Hormones and Appetite
Different foods affect hormones that regulate hunger and fat storage:
Refined carbs can spike insulin, leading to energy crashes and increased hunger.
Protein and fiber help regulate appetite hormones, promoting satiety.
Calculators Are Just Estimates
Online calorie calculators and trackers provide rough estimates of your BMR, but they can’t account for individual differences like genetics, gut microbiome, stress, sleep, or hormone levels.
Practical Ways to Improve Energy Balance
Focus on food quality, not just calories. Whole foods rich in protein and fiber keep you fuller longer and require more energy to digest.
Prioritize strength training. Building muscle increases your basal metabolic rate, helping you burn more calories at rest.
Move more outside the gym. Take the stairs, walk after meals, stand instead of sit, small habits add up.
Listen to your body. Pay attention to hunger, energy levels, and cravings instead of relying solely on calculators.
Key Takeaways
No matter what your goal is with your energy balance it's good to focus on:
Eating whole, nutrient-dense foods.
Staying active daily.
Building and maintaining muscle.
Paying attention to how your body feels
Look at these factors, see if your balance is positive, negative, or neutral, and modify as needed to meet your goals.
Sources:
https://pmc.ncbi.nlm.nih.gov/articles/PMC6003580/
https://blog.nasm.org/a-guide-to-energy-balance