Energy Needs and Balance

Energy and Weight: Your Body’s Fuel Story 🔋

The Big Picture

Imagine your body is like a piggy bank. But instead of coins, you put in food energy and take out activity energy. If you put in more than you take out, your piggy bank gets fuller (you gain weight). If you take out more than you put in, it gets emptier (you lose weight). Simple!

1. Energy Balance ⚖️

What Is It?

Energy balance is like a seesaw at the playground.

• One side: Energy IN (food you eat)
• Other side: Energy OUT (everything your body does)

When both sides are equal, you stay the same weight. When one side is heavier, things change!

The Three States

graph TD
    A["Energy Balance"] --> B["Equal: Stay Same Weight"]
    A --> C["More IN: Gain Weight"]
    A --> D["More OUT: Lose Weight"]

Example:

• Maya eats 2000 energy units and uses 2000. Her seesaw is balanced!
• If Maya eats 2500 but only uses 2000, she stores the extra 500.

2. Calories and Kilocalories 🍎

What’s a Calorie?

A calorie is how we measure food energy. Think of it like measuring milk in cups or distance in steps.

Fun Fact: The “Calories” on food labels are actually kilocalories (kcal).

Real Example

When your cereal box says “100 Calories,” it really means 100 kilocalories. That’s enough energy to:

• Walk for about 20 minutes
• Run for about 10 minutes
• Power a light bulb for 1.5 hours!

Simple math: 1 Calorie (food label) = 1 kcal = 1000 tiny calories

3. Basal Metabolic Rate (BMR) 💤

Your Body at Rest

Even when you’re sleeping, your body is working hard!

BMR = Energy your body needs just to stay alive

This includes:

• 🫀 Heart beating
• 🫁 Lungs breathing
• 🧠 Brain thinking
• 🌡️ Body staying warm

How Much Is It?

BMR uses about 60-70% of all your daily energy! Most of your food energy goes to just… being alive.

Example: A 10-year-old might have a BMR of about 1200-1400 kcal per day. That’s like having an engine running inside you, even when you’re doing nothing!

What Affects BMR?

graph TD
    A["BMR Depends On"] --> B["Age: Kids/Teens = Higher"]
    A --> C["Size: Bigger = Higher"]
    A --> D["Muscle: More = Higher"]
    A --> E["Gender: Boys slightly higher"]

4. Total Daily Energy Expenditure (TDEE) 📊

The Full Picture

TDEE is ALL the energy you use in one day. Think of it as adding up everything:

TDEE = BMR + Activity + Food Processing

It’s like counting all the money leaving your piggy bank:

• Rent (BMR) - the biggest expense
• Fun activities (Physical Activity)
• Bank fees (Processing food)

The TDEE Pie

Example: If your TDEE is 2000 kcal:

• ~1300 kcal just for body functions
• ~500 kcal for running, playing, walking
• ~200 kcal for digesting your food

5. Thermic Effect of Food (TEF) 🔥

Eating Burns Energy!

Here’s a cool secret: Your body uses energy to get energy from food!

It’s like paying a delivery fee. When food arrives (you eat), your body has to:

• Break it down
• Sort the nutrients
• Store or use them

This work = Thermic Effect of Food

Different Foods, Different Fees

Example: If you eat 100 kcal of chicken (protein):

• Your body uses ~25 kcal just to process it
• You only “keep” about 75 kcal

But if you eat 100 kcal of butter (fat):

• Your body uses only ~3 kcal to process it
• You “keep” about 97 kcal

6. Physical Activity Level (PAL) 🏃

How Active Are You?

PAL is a number that shows how active someone is compared to just resting.

Formula: PAL = TDEE ÷ BMR

Activity Categories

graph TD
    A["Physical Activity Level"] --> B["Sedentary: 1.2-1.4"]
    A --> C["Light: 1.4-1.6"]
    A --> D["Moderate: 1.6-1.8"]
    A --> E["Active: 1.8-2.0"]
    A --> F["Very Active: 2.0-2.4"]

What Do These Mean?

Example:

• Sam has BMR of 1500 kcal
• Sam plays soccer every day (PAL = 1.8)
• Sam’s TDEE = 1500 × 1.8 = 2700 kcal

Putting It All Together 🎯

The Energy Story Flow

graph TD
    A["Food Eaten"] --> B["Calories In"]
    B --> C["TDEE: Calories Out"]
    C --> D["BMR: 60-70%"]
    C --> E["Activity: 15-30%"]
    C --> F["TEF: 5-10%"]
    B --> G{Balance?}
    G --> H["Equal: Weight Stable"]
    G --> I["More In: Weight Gain"]
    G --> J["More Out: Weight Loss"]

Remember This!

1. Energy Balance = Your body’s seesaw
2. Calories/kcal = Energy measurement units
3. BMR = Energy to stay alive (biggest part!)
4. TDEE = All energy used in a day
5. TEF = Energy to process food
6. PAL = How active you are

Quick Real-Life Example

Meet Alex, age 12:

Alex eats exactly what Alex uses. The piggy bank stays the same!

If Alex wants to have more energy for growth:

• Eat a bit more healthy food
• The extra goes to building stronger bones and muscles

The Takeaway 💡

Your body is an amazing energy machine! It:

• Burns energy just being alive (BMR)
• Burns extra when you move (Activity)
• Even burns energy eating (TEF)

Understanding these helps you:

• Make smart food choices
• Know why exercise matters
• Keep your energy seesaw balanced!

You’re now an Energy Expert! 🏆