Energy and Energy Balance

What Energy and Energy Balance covers

Energy and Energy Balance is examined in Unit AS 2, Diet, Lifestyle and Health — examined, compulsory. It covers why the body needs energy, basal metabolic rate and physical activity level, energy EARs through life and energy balance and weight change.

The 4 subtopics

Each one has its own page.

• Why the body needs energyBasal and other energy needs, kilocalories and kilojoules, energy values of the macronutrients and alcohol, bomb calorimetry and worked energy calculations.Open →
• Basal metabolic rate and physical activity levelWhat affects basal metabolic rate, physical activity level, NEAT, the thermic effect of food, and estimating total energy expenditure.Open →
• Energy EARs through lifeEstimated Average Requirements for energy, SACN's 2011 revision, how requirements change from infancy to old age and in pregnancy and breastfeeding, and their limits for individuals.Open →
• Energy balance and weight changePositive and negative energy balance, appetite regulation, energy density, why weight loss slows, and worked weight change calculations.Open →

What you need to know

Answer each one before you reveal it.

Take Energy and Energy Balance further

The same content, four other ways.

Commonly confused

Pairs that lose marks when they are blurred together.

• Basal metabolic rate vs Physical activity level

  Basal metabolic rate: the energy used at complete rest to keep the body alive. Physical activity level: the ratio of total daily expenditure to resting expenditure.

• Positive energy balance vs Negative energy balance

  Positive energy balance: a state in which intake exceeds expenditure and weight rises. Negative energy balance: a state in which expenditure exceeds intake and weight falls.

• Kilocalorie vs Kilojoule

  Kilocalorie: the heat needed to raise one kilogram of water by one degree Celsius. Kilojoule: the work done by a force of one thousand newtons moving through one metre.

Questions from this topic

Each one with the model answer underneath.

1. 1

   Why does the body need a constant supply of energy even at complete rest?

   Model answer

   Energy is needed at rest to keep the heart beating, the lungs breathing and the nerves working. Energy also maintains body temperature and powers chemical reactions in every cell.

2. 2

   Name four uses of energy in the body beyond basal needs.

   Model answer

   Energy beyond basal needs fuels physical activity, growth, the digestion and processing of food, and milk production during lactation.

3. 3

   Why do children and teenagers need energy for growth?

   Model answer

   Growth requires energy to build new tissue such as bone, muscle and organs. Growing children also have a high BMR for their body size.

4. 4

   How is energy from food made available to the body's cells?

   Model answer

   Glucose, fatty acids and amino acids are oxidised in cell respiration. The energy released is captured as ATP, which cells use to power their work.

5. 5

   What units are used to measure the energy in food?

   Model answer

   Food energy is measured in kilocalories (kcal) or kilojoules (kJ). One kilocalorie equals 4.184 kilojoules.

6. 6

   State the energy provided by one gram each of protein, fat, carbohydrate and alcohol.

   Model answer

   Protein and carbohydrate each provide 4 kcal per gram. Fat provides 9 kcal per gram and alcohol provides 7 kcal per gram.

What is inside Levo

Six ways to work the same material.

Energy and Energy Balance revision questions

What does Energy and Energy Balance cover in CCEA A-Level Nutrition and Food Science?

4 subtopics: why the body needs energy, basal metabolic rate and physical activity level, energy ears through life and energy balance and weight change. Each one has its own page with questions and model answers.

How is Energy and Energy Balance organised?

By the CCEA 3310 specification, subtopic by subtopic, so it matches the order you are taught it in.