1.4 Identify energy requirements of various different age groups

This guide will help you answer 1.4 Identify energy requirements of various different age groups.

Everyone needs energy to function, grow, and stay healthy. Energy comes from the food and drinks we consume. The energy we use is measured in kilocalories (kcal). How much energy a person needs changes throughout life. It can depend on age, gender, body size, activity level, health status, and growth rate.

Understanding how these needs vary between age groups helps workers offer accurate advice and support. Providing the right energy reduces health risks and helps everyone lead an active, balanced life.

What Are Energy Requirements?

Energy requirements refer to the number of kilocalories needed each day to sustain a person’s body processes and activity. This energy is used for breathing, thinking, maintaining body temperature, moving, and repairing cells.

The total energy requirement is made up of three main parts:

• Basal metabolic rate (BMR): The energy the body uses at rest, just to keep alive.
• Physical activity: The energy needed for all movement, from walking to running or even fidgeting.
• Growth and repair: The extra energy needed by growing bodies and for repairing tissues.

Different age groups have unique requirements, shaped by their stage of life.

Energy Requirements for Infants and Toddlers (0-3 years)

Infants and toddlers grow rapidly. This is the fastest period of growth outside of the womb. Their bodies use a lot of energy for both growth and daily activity.

Key points:

• Babies (0-12 months): Their energy needs are high for their size. Milk (breast or formula) provides all energy for the first 6 months. At around 6 months, solid foods are introduced alongside milk.
• 1-3 years: As children begin to walk and explore, activity levels increase. Energy needs rise slightly, but not as steeply as during infancy.

Average estimated daily energy needs:

• 0-3 months: Around 550 kcal (boys), 500 kcal (girls)
• 4-6 months: Around 645 kcal (boys), 570 kcal (girls)
• 7-12 months: Around 825 kcal (boys), 765 kcal (girls)
• 1-3 years: About 1000–1300 kcal per day

Factors influencing needs at this age:

• Growth spurts may increase appetite.
• More active toddlers need more energy.
• Illness may reduce appetite and temporarily decrease energy needs.

Energy Requirements for Early Childhood (4-10 years)

Children in this age group are highly active and continue to grow, though not as quickly as babies and toddlers. Developing bones, muscles, and organs all require a reliable supply of energy from food each day.

Estimated daily needs:

• 4-6 years: 1300–1800 kcal, depending on activity and gender
• 7-10 years: 1700–2100 kcal, depending on activity and gender

Within this group:

• Boys often use slightly more energy due to a tendency for higher muscle mass and activity.
• Children doing lots of sport or play outside use more energy.

Energy requirements support cognitive growth too—concentration and learning are better when diets are balanced and energy needs are met.

Energy Requirements for Adolescents (11-18 years)

Adolescence includes puberty—a time of fast and sometimes uneven growth. The body demands much more energy to support these changes, so appetite can increase noticeably.

Estimated needs:

• 11-14 years: Girls 1900–2200 kcal, Boys 2100–2500 kcal
• 15-18 years: Girls 2100–2500 kcal, Boys 2500–3000 kcal

Points to remember:

• Physical activity at this age varies widely and has a big effect on energy needs.
• Adolescents’ growth rates may not be steady, so some teens may need more energy at certain times.
• Emotional changes can affect eating habits—some may eat too little or too much.

Balancing these needs through healthy foods helps teens grow properly and supports emotional wellbeing.

Energy Requirements for Adults (19-64 years)

Adult energy needs are shaped mainly by body size, muscle mass, gender, and activity levels. Unlike earlier stages, adults are not growing but must maintain muscle, organ function, and daily activity.

Estimated average requirements:

• Women (non-pregnant, non-breastfeeding): 1800–2200 kcal, depending on activity
• Men: 2200–2800 kcal, depending on activity

Changes during adulthood include:

• Muscle mass tends to decrease with age, lowering the basal metabolic rate.
• Individuals doing manual jobs, regular exercise, or sports may need more energy.
• Adults with sedentary lifestyles need less and risk weight gain if intake is not adjusted.

Other considerations:

• Pregnancy increases energy needs, especially in the second and third trimester.
• Breastfeeding mothers need extra calories for milk production.

Energy Requirements for Older Adults (65+ years)

Older adults may need fewer calories than younger adults. This is mostly due to a reduction in physical activity and loss of muscle mass.

Average needs:

• Women over 65: About 1600–2000 kcal per day
• Men over 65: About 2000–2500 kcal per day

Points to keep in mind:

• Metabolism slows as people age.
• Activity levels usually reduce due to health issues or less mobility.
• Some may need more due to chronic illness or if they remain physically active.
• Protection against undernutrition is important—older people might eat less because of dental, taste, or digestive changes. Even with lower energy needs, nutrient-rich foods are important.

Comparing Energy Requirements Across Age Groups

Energy needs are not constant; they rise and fall throughout life. To summarise:

• Infants use a lot of energy per kilogram due to rapid growth.
• Toddlers and young children are very active and still growing fast.
• School-age children’s needs increase with activity and growth spurts.
• Teens have high needs, particularly boys, because of puberty-related growth.
• Adults’ needs stabilise based on lifestyle and muscle mass.
• Older adults need less due to slowing metabolism and muscle loss.

Environmental and lifestyle factors play their part. In all cases, eating patterns should support energy requirements without promoting excess weight gain or loss.

Factors Affecting Individual Needs

Besides age, several personal factors affect someone’s energy requirements:

• Gender: Males usually need more than females, due to more muscle and higher BMR.
• Activity level: Active individuals need more energy for movement and exercise.
• Weight and height: Larger bodies need more energy to function.
• Health status: Illness, injury, or certain conditions may raise or lower energy needs.
• Growth or life stage: Periods of rapid growth, pregnancy, or breastfeeding demand more energy.

Monitoring energy requirements is important to avoid underfeeding or overfeeding, both of which can affect health.

Risks of Not Meeting Energy Needs

If energy needs are not met, or if they are greatly exceeded, health will suffer.

Under-eating can cause:

• Poor growth in children
• Weak immune system
• Fatigue and weakness
• Muscle wasting in older adults

Overeating can cause:

• Weight gain and obesity
• Increased risk of type 2 diabetes, heart disease, and some cancers
• Strain on joints and organs

Matching food intake to energy requirements helps keep weight steady and promotes long-term wellbeing.

Practical Ways to Meet Energy Requirements

Getting the right balance is easier with planning. Tips include:

• Offer regular, balanced meals and snacks, especially for children and older people at risk of undernutrition.
• Encourage a mix of foods: starchy carbohydrates, protein-rich foods, dairy or alternatives, fruit, and vegetables.
• For young children, energy-dense snacks (such as cheese, yoghurt, or nut butters) give extra calories.
• Older adults may need softer foods but still require balance and variety.
• Support adolescents to make healthy choices, as this age group often skips meals or eats too much convenience food.
• Physical activity should match energy intake to keep weight and health stable.

Final Thoughts

Supporting people’s health at every stage of life means recognising the changing energy needs from infancy to old age. No single figure suits everyone, but good estimates and regular reviews help keep food intake safe and beneficial.

Health workers, carers, and support staff have a special role. Being aware of these needs, they help to avoid both under-nutrition and unwanted weight gain. Sensible meal planning, attention to activity levels, and an understanding ear all make a positive difference. Remember that while energy needs shift, the principles behind meeting them—balance, variety, and portion control—stay the same.

Through careful guidance, you help each person receive the right amount of energy for growth, healing, movement, and comfort. This is key to promoting healthy development in children, sustaining adults in work and family life, and protecting older people from frailty. Every stage matters, and matching energy intake to needs is an important part of lifelong health.